SOLR-13434: OpenTracing support for Solr (#685)

dev-tools/idea/.idea/libraries/Solr_jaeger_tracer_configurator_library.xml

@@ -0,0 +1,10 @@
+<component name="libraryTable">
+  <library name="Solr jaeger tracer configurator library">
+    <CLASSES>
+      <root url="file://$PROJECT_DIR$/solr/contrib/jaegertracer-configurator/lib" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+    <jarDirectory url="file://$PROJECT_DIR$/solr/contrib/jaegertracer-configurator/lib" recursive="false" />
+  </library>
+</component>

dev-tools/idea/.idea/modules.xml

@@ -59,6 +59,7 @@
       <module group="Solr/Contrib" filepath="$PROJECT_DIR$/solr/contrib/langid/langid.iml" />
       <module group="Solr/Contrib" filepath="$PROJECT_DIR$/solr/contrib/ltr/ltr.iml" />
       <module group="Solr/Contrib" filepath="$PROJECT_DIR$/solr/contrib/prometheus-exporter/prometheus-exporter.iml" />
+      <module group="Solr/Contrib" filepath="$PROJECT_DIR$/solr/contrib/jaegertracer-configurator/jaegertracer-configurator.iml" />
       <module group="Solr/Contrib" filepath="$PROJECT_DIR$/solr/contrib/velocity/velocity.iml" />
     </modules>
   </component>

dev-tools/idea/solr/contrib/jaegertracer-configurator/jaegertracer-configurator.iml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="false">
+    <output url="file://$MODULE_DIR$/../../../idea-build/solr/contrib/jaegertracer-configurator/classes/java" />
+    <output-test url="file://$MODULE_DIR$/../../../idea-build/solr/contrib/jaegertracer-configurator/classes/test" />
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src/test" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/src/test-files" type="java-test-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/src/java" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" scope="TEST" name="JUnit" level="project" />
+    <orderEntry type="library" name="Solr core library" level="project" />
+    <orderEntry type="library" name="Solrj library" level="project" />
+    <orderEntry type="module-library" scope="TEST">
+      <library>
+        <CLASSES>
+          <root url="file://$MODULE_DIR$/lib" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+        <jarDirectory url="file://$MODULE_DIR$/lib" recursive="false" />
+      </library>
+    </orderEntry>
+    <orderEntry type="module" scope="TEST" module-name="lucene-test-framework" />
+    <orderEntry type="module" scope="TEST" module-name="solr-test-framework" />
+    <orderEntry type="library" name="Solr core library" level="project" />
+    <orderEntry type="library" name="Solrj library" level="project" />
+    <orderEntry type="library" name="Solr jaeger tracer configurator library" level="project" />
+    <orderEntry type="module" module-name="lucene-core" />
+    <orderEntry type="module" module-name="solr-core" />
+    <orderEntry type="module" module-name="solrj" />
+    <orderEntry type="module" module-name="analysis-common" />
+  </component>
+</module>

dev-tools/idea/solr/test-framework/solr-test-framework.iml

@@ -16,6 +16,7 @@
     <orderEntry type="library" name="Solr core library" level="project" />
     <orderEntry type="library" name="Solr example library" level="project" />
     <orderEntry type="library" name="Solrj library" level="project" />
+    <orderEntry type="library" name="Solr test framework library" level="project" />
     <orderEntry type="module" module-name="lucene-test-framework" />
     <orderEntry type="module" module-name="analysis-common" />
     <orderEntry type="module" module-name="solrj" />

dev-tools/maven/solr/contrib/jaegertracer-configurator/pom.xml.template

@@ -0,0 +1,80 @@
+<!--
+  Licensed to the Apache Software Foundation (ASF) under one
+  or more contributor license agreements.  See the NOTICE file
+  distributed with this work for additional information
+  regarding copyright ownership.  The ASF licenses this file
+  to you under the Apache License, Version 2.0 (the
+  "License"); you may not use this file except in compliance
+  with the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing,
+  software distributed under the License is distributed on an
+  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+  KIND, either express or implied.  See the License for the
+  specific language governing permissions and limitations
+  under the License.
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>org.apache.solr</groupId>
+    <artifactId>solr-parent</artifactId>
+    <version>@version@</version>
+    <relativePath>../../pom.xml</relativePath>
+  </parent>
+  <groupId>org.apache.solr</groupId>
+  <artifactId>solr-jaegertracer-configurator</artifactId>
+  <packaging>jar</packaging>
+  <name>Apache Solr Jaeger Tracer Configurator Package</name>
+  <description>
+    Apache Solr Jaeger Tracer Configurator Package
+  </description>
+  <properties>
+    <module-directory>solr/contrib/jaegertracer-configurator</module-directory>
+    <relative-top-level>../../../..</relative-top-level>
+    <module-path>${relative-top-level}/${module-directory}</module-path>
+  </properties>
+  <scm>
+    <connection>scm:git:${vc-anonymous-base-url}</connection>
+    <developerConnection>scm:git:${vc-dev-base-url}</developerConnection>
+    <url>${vc-browse-base-url};f=${module-directory}</url>
+  </scm>
+  <dependencies>
+    <dependency>
+      <!-- lucene-test-framework dependency must be declared before lucene-core -->
+      <!-- This dependency cannot be put into solr-parent, because local        -->
+      <!-- dependencies are always ordered before inherited dependencies.       -->
+      <groupId>org.apache.lucene</groupId>
+      <artifactId>lucene-test-framework</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.solr</groupId>
+      <artifactId>solr-test-framework</artifactId>
+      <scope>test</scope>
+    </dependency>
+    @solr-jaegertracer-configurator.internal.dependencies@
+    @solr-jaegertracer-configurator.external.dependencies@
+    @solr-jaegertracer-configurator.internal.test.dependencies@
+    @solr-jaegertracer-configurator.external.test.dependencies@
+  </dependencies>
+  <build>
+    <sourceDirectory>${module-path}/src/java</sourceDirectory>
+    <testSourceDirectory>${module-path}/src/test</testSourceDirectory>
+    <testResources>
+      <testResource>
+        <directory>${module-path}/src/test-files</directory>
+      </testResource>
+      <testResource>
+        <directory>${top-level}/dev-tools/maven/solr</directory>
+        <includes>
+          <include>maven.testlogging.properties</include>
+        </includes>
+      </testResource>
+    </testResources>
+  </build>
+</project>

dev-tools/maven/solr/contrib/pom.xml.template

@@ -37,6 +37,7 @@
     <module>dataimporthandler</module>
     <module>dataimporthandler-extras</module>
     <module>extraction</module>
+    <module>jaegertracer-configurator</module>
     <module>langid</module>
     <module>ltr</module>
     <module>prometheus-exporter</module>

lucene/ivy-versions.properties

@@ -66,9 +66,19 @@ io.dropwizard.metrics.version = 4.0.5
 /io.dropwizard.metrics/metrics-jmx = ${io.dropwizard.metrics.version}
 /io.dropwizard.metrics/metrics-jvm = ${io.dropwizard.metrics.version}
 
+io.jaegertracing.version = 0.35.5
+/io.jaegertracing/jaeger-core = ${io.jaegertracing.version}
+/io.jaegertracing/jaeger-thrift = ${io.jaegertracing.version}
+
 io.netty.netty-all.version = 4.0.52.Final
 /io.netty/netty-all = ${io.netty.netty-all.version}
 
+io.opentracing.version = 0.33.0
+/io.opentracing/opentracing-api = ${io.opentracing.version}
+/io.opentracing/opentracing-mock = ${io.opentracing.version}
+/io.opentracing/opentracing-noop = ${io.opentracing.version}
+/io.opentracing/opentracing-util = ${io.opentracing.version}
+
 io.prometheus.version = 0.2.0
 /io.prometheus/simpleclient = ${io.prometheus.version}
 /io.prometheus/simpleclient_common = ${io.prometheus.version}
@@ -182,6 +192,9 @@ org.apache.poi.version = 4.0.0
 /org.apache.poi/poi-ooxml-schemas = ${org.apache.poi.version}
 /org.apache.poi/poi-scratchpad = ${org.apache.poi.version}
 
+org.apache.thrift.version = 0.12.0
+/org.apache.thrift/libthrift = ${org.apache.thrift.version}
+
 org.apache.tika.version = 1.19.1
 /org.apache.tika/tika-core = ${org.apache.tika.version}
 /org.apache.tika/tika-java7 = ${org.apache.tika.version}

solr/contrib/jaegertracer-configurator/README.txt

@@ -0,0 +1,32 @@
+Welcome to Apache Solr Jaeger Tracer Configurator
+========
+
+Apache Solr Jaeger Tracer Configurator (solr-jaegertracer) provides a way for you to expose Solr's tracing to Jaeger.
+
+# Setup Jaeger Tracer Configurator
+
+Note that all library of solr-jaegertracer must be included in the classpath of all nodes then Jaeger tracer can be setup in `solr.xml` like this:
+
+```
+<tracerConfig name="tracerConfig" class="org.apache.solr.jaeger.JaegerTracerConfigurator">
+  <str name="agentHost">localhost</str>
+  <int name="agentPort">5775</int>
+  <bool name="logSpans">true</bool>
+  <int name="flushInterval">1000</int>
+  <int name="maxQueueSize">10000</int>
+</tracerConfig>
+```
+
+List of parameters for JaegerTracerConfigurator include:
+|Parameter|Type|Required|Default|Description|
+|---------|----|--------|-------|-----------|
+|agentHost|string|Yes||The host of Jaeger backend|
+|agentPort|int|Yes||The port of Jaeger port|
+|logsSpans|bool|No|true|Whether the tracer should also log the spans|
+|flushInterval|int|No|5000|The tracer's flush interval (ms)|
+|maxQueueSize|int|No|10000|The tracer's maximum queue size|
+
+Other parameters which are not listed above can be configured using System Properties or Environment Variables. The full list are listed at [Jaeger-README](https://github.com/jaegertracing/jaeger-client-java/blob/master/jaeger-core/README.md).
+
+By default the sampling rate is 0.1%, this value can be changed by updating
+key `samplePercentage` of cluster properties. I.e: `/admin/collections?action=CLUSTERPROP&name=propertyName&samplePercentage=100`.

solr/contrib/jaegertracer-configurator/build.xml

@@ -0,0 +1,34 @@
+<?xml version="1.0"?>
+
+<!--
+    Licensed to the Apache Software Foundation (ASF) under one or more
+    contributor license agreements.  See the NOTICE file distributed with
+    this work for additional information regarding copyright ownership.
+    The ASF licenses this file to You under the Apache License, Version 2.0
+    the "License"); you may not use this file except in compliance with
+    the License.  You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+ -->
+
+<project name="solr-jaegertracer-configurator" default="default">
+
+  <description>
+    Jaeger tracer configurator for tracing Solr using OpenTracing with Jaeger backend.
+  </description>
+
+  <import file="../contrib-build.xml"/>
+
+  <path id="classpath">
+    <path refid="solr.base.classpath"/>
+  </path>
+
+  <target name="compile-core" depends="solr-contrib-build.compile-core"/>
+
+</project>

solr/contrib/jaegertracer-configurator/ivy.xml

@@ -0,0 +1,32 @@
+<!--
+   Licensed to the Apache Software Foundation (ASF) under one
+   or more contributor license agreements.  See the NOTICE file
+   distributed with this work for additional information
+   regarding copyright ownership.  The ASF licenses this file
+   to you under the Apache License, Version 2.0 (the
+   "License"); you may not use this file except in compliance
+   with the License.  You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing,
+   software distributed under the License is distributed on an
+   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+   KIND, either express or implied.  See the License for the
+   specific language governing permissions and limitations
+   under the License.
+-->
+<ivy-module version="2.0">
+  <info organisation="org.apache.solr" module="jaegertracer-configurator"/>
+  <configurations defaultconfmapping="compile->master;test->master">
+    <conf name="compile" transitive="false"/>
+    <conf name="test" transitive="false"/>
+  </configurations>
+  <dependencies>
+    <dependency org="io.jaegertracing" name="jaeger-core" rev="${/io.jaegertracing/jaeger-core}" conf="compile"/>
+    <dependency org="io.jaegertracing" name="jaeger-thrift" rev="${/io.jaegertracing/jaeger-thrift}" conf="compile"/>
+    <dependency org="org.apache.thrift" name="libthrift" rev="${/org.apache.thrift/libthrift}" conf="compile"/>
+
+    <exclude org="*" ext="*" matcher="regexp" type="${ivy.exclude.types}"/>
+  </dependencies>
+</ivy-module>

solr/contrib/jaegertracer-configurator/src/java/org/apache/solr/jaeger/JaegerTracerConfigurator.java

@@ -0,0 +1,89 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.jaeger;
+
+import io.jaegertracing.Configuration;
+import io.jaegertracing.internal.samplers.ConstSampler;
+import io.opentracing.Tracer;
+import org.apache.solr.common.util.NamedList;
+import org.apache.solr.core.TracerConfigurator;
+
+public class JaegerTracerConfigurator extends TracerConfigurator {
+  public static final String AGENT_HOST = "agentHost";
+  public static final String AGENT_PORT = "agentPort";
+  public static final String LOG_SPANS = "logSpans";
+  public static final String FLUSH_INTERVAL = "flushInterval";
+  public static final String MAX_QUEUE_SIZE = "maxQueueSize";
+
+  private volatile Tracer tracer;
+
+  @Override
+  public Tracer getTracer() {
+    return tracer;
+  }
+
+  @Override
+  public void init(NamedList args) {
+    Object host = args.get(AGENT_HOST);
+    if (!(host instanceof String)) {
+      throw new IllegalArgumentException("Expected a required string for param '" + AGENT_HOST + "'");
+    }
+
+    Object portArg = args.get(AGENT_PORT);
+    if (!(portArg instanceof Integer)) {
+      throw new IllegalArgumentException("Expected a required int for param '" + AGENT_PORT + "'");
+    }
+    int port = (Integer) portArg;
+
+    Boolean logSpans = args.getBooleanArg(LOG_SPANS);
+    if (logSpans == null)
+      logSpans = true;
+
+    Object flushIntervalArg = args.get(FLUSH_INTERVAL);
+    if (flushIntervalArg != null && !(flushIntervalArg instanceof Integer)) {
+      throw new IllegalArgumentException("Expected a required int for param '" + FLUSH_INTERVAL +"'");
+    }
+    int flushInterval = flushIntervalArg == null ? 1000 : (Integer) flushIntervalArg;
+
+    Object maxQueueArgs = args.get(MAX_QUEUE_SIZE);
+    if (maxQueueArgs != null && !(maxQueueArgs instanceof Integer)) {
+      throw new IllegalArgumentException("Expected a required int for param '" + MAX_QUEUE_SIZE +"'");
+    }
+    int maxQueue = maxQueueArgs == null ? 10000 : (Integer) maxQueueArgs;
+
+    Configuration.SamplerConfiguration samplerConfig = new Configuration.SamplerConfiguration()
+        .withType(ConstSampler.TYPE)
+        .withParam(1);
+
+    Configuration.ReporterConfiguration reporterConfig = Configuration.ReporterConfiguration.fromEnv();
+    Configuration.SenderConfiguration senderConfig = reporterConfig.getSenderConfiguration()
+        .withAgentHost(host.toString())
+        .withAgentPort(port);
+
+    reporterConfig.withLogSpans(logSpans)
+        .withFlushInterval(flushInterval)
+        .withMaxQueueSize(maxQueue)
+        .withSender(senderConfig);
+    tracer = new Configuration("solr")
+        .withSampler(samplerConfig)
+        .withReporter(reporterConfig)
+        .getTracer();
+  }
+
+
+}

solr/contrib/jaegertracer-configurator/src/test-files/solr/collection1/conf/schema.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements.  See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ (the "License"); you may not use this file except in compliance with
+ the License.  You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+<schema name="minimal" version="1.1">
+  <fieldType name="string" class="solr.StrField"/>
+  <fieldType name="int" class="${solr.tests.IntegerFieldType}" docValues="${solr.tests.numeric.dv}" precisionStep="0" omitNorms="true" positionIncrementGap="0"/>
+  <fieldType name="long" class="${solr.tests.LongFieldType}" docValues="${solr.tests.numeric.dv}" precisionStep="0" omitNorms="true" positionIncrementGap="0"/>
+  <dynamicField name="*" type="string" indexed="true" stored="true"/>
+  <!-- for versioning -->
+  <field name="_version_" type="long" indexed="true" stored="true"/>
+  <field name="_root_" type="string" indexed="true" stored="true" multiValued="false" required="false"/>
+  <field name="id" type="string" indexed="true" stored="true"/>
+  <dynamicField name="*_s"  type="string"  indexed="true"  stored="true" />
+  <uniqueKey>id</uniqueKey>
+</schema>

solr/contrib/jaegertracer-configurator/src/test-files/solr/collection1/conf/solrconfig.xml

@@ -0,0 +1,51 @@
+<?xml version="1.0" ?>
+
+<!--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements.  See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ (the "License"); you may not use this file except in compliance with
+ the License.  You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+
+<!-- Minimal solrconfig.xml with /select, /admin and /update only -->
+
+<config>
+
+  <dataDir>${solr.data.dir:}</dataDir>
+
+  <directoryFactory name="DirectoryFactory"
+                    class="${solr.directoryFactory:solr.NRTCachingDirectoryFactory}"/>
+  <schemaFactory class="ClassicIndexSchemaFactory"/>
+
+  <luceneMatchVersion>${tests.luceneMatchVersion:LATEST}</luceneMatchVersion>
+
+  <updateHandler class="solr.DirectUpdateHandler2">
+    <commitWithin>
+      <softCommit>${solr.commitwithin.softcommit:true}</softCommit>
+    </commitWithin>
+    <updateLog class="${solr.ulog:solr.UpdateLog}"></updateLog>
+  </updateHandler>
+
+  <requestHandler name="/select" class="solr.SearchHandler">
+    <lst name="defaults">
+      <str name="echoParams">explicit</str>
+      <str name="indent">true</str>
+      <str name="df">text</str>
+    </lst>
+
+  </requestHandler>
+  <indexConfig>
+    <mergeScheduler class="${solr.mscheduler:org.apache.lucene.index.ConcurrentMergeScheduler}"/>
+:  </indexConfig>
+</config>
+

solr/contrib/jaegertracer-configurator/src/test-files/solr/solr.xml

@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements.  See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ (the "License"); you may not use this file except in compliance with
+ the License.  You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+
+<!--
+ solr.xml mimicking the old default solr.xml
+-->
+
+<solr>
+
+  <str name="shareSchema">${shareSchema:false}</str>
+  <str name="configSetBaseDir">${configSetBaseDir:configsets}</str>
+  <str name="coreRootDirectory">${coreRootDirectory:.}</str>
+  <str name="collectionsHandler">${collectionsHandler:solr.CollectionsHandler}</str>
+
+  <shardHandlerFactory name="shardHandlerFactory" class="HttpShardHandlerFactory">
+    <str name="urlScheme">${urlScheme:}</str>
+    <int name="socketTimeout">${socketTimeout:90000}</int>
+    <int name="connTimeout">${connTimeout:15000}</int>
+    <str name="shardsWhitelist">${solr.tests.shardsWhitelist:}</str>
+  </shardHandlerFactory>
+
+  <tracerConfig name="tracerConfig" class="org.apache.solr.jaeger.JaegerTracerConfigurator">
+    <str name="agentHost">localhost</str>
+    <int name="agentPort">5775</int>
+    <bool name="logSpans">true</bool>
+    <int name="flushInterval">1000</int>
+    <int name="maxQueueSize">10000</int>
+  </tracerConfig>
+
+  <solrcloud>
+    <str name="host">127.0.0.1</str>
+    <int name="hostPort">${hostPort:8983}</int>
+    <str name="hostContext">${hostContext:solr}</str>
+    <int name="zkClientTimeout">${solr.zkclienttimeout:30000}</int>
+    <bool name="genericCoreNodeNames">${genericCoreNodeNames:true}</bool>
+    <int name="leaderVoteWait">${leaderVoteWait:10000}</int>
+    <int name="distribUpdateConnTimeout">${distribUpdateConnTimeout:45000}</int>
+    <int name="distribUpdateSoTimeout">${distribUpdateSoTimeout:340000}</int>
+    <str name="zkCredentialsProvider">${zkCredentialsProvider:org.apache.solr.common.cloud.DefaultZkCredentialsProvider}</str>
+    <str name="zkACLProvider">${zkACLProvider:org.apache.solr.common.cloud.DefaultZkACLProvider}</str>
+  </solrcloud>
+  <metrics>
+    <reporter name="default" class="org.apache.solr.metrics.reporters.SolrJmxReporter">
+      <str name="rootName">solr_${hostPort:8983}</str>
+    </reporter>
+  </metrics>
+</solr>

solr/contrib/jaegertracer-configurator/src/test/org/apache/solr/jaeger/TestJaegerConfigurator.java

@@ -0,0 +1,124 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.jaeger;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.solr.SolrTestCaseJ4;
+import org.apache.solr.client.solrj.request.CollectionAdminRequest;
+import org.apache.solr.cloud.MiniSolrCloudCluster;
+import org.apache.solr.cloud.SolrCloudTestCase;
+import org.apache.solr.common.SolrException;
+import org.apache.solr.common.cloud.ZkStateReader;
+import org.apache.solr.common.util.NamedList;
+import org.apache.solr.common.util.TimeSource;
+import org.apache.solr.util.TimeOut;
+import org.apache.solr.util.tracing.GlobalTracer;
+import org.junit.Test;
+
+import static org.apache.solr.jaeger.JaegerTracerConfigurator.AGENT_HOST;
+import static org.apache.solr.jaeger.JaegerTracerConfigurator.AGENT_PORT;
+import static org.apache.solr.jaeger.JaegerTracerConfigurator.FLUSH_INTERVAL;
+import static org.apache.solr.jaeger.JaegerTracerConfigurator.LOG_SPANS;
+import static org.apache.solr.jaeger.JaegerTracerConfigurator.MAX_QUEUE_SIZE;
+
+public class TestJaegerConfigurator extends SolrTestCaseJ4 {
+
+  @Test
+  public void testInjected() throws Exception{
+    MiniSolrCloudCluster cluster = new SolrCloudTestCase.Builder(1, createTempDir())
+        .addConfig("config", TEST_PATH().resolve("collection1").resolve("conf"))
+        .withSolrXml(getFile("solr/solr.xml").toPath())
+        .build();
+    CollectionAdminRequest.setClusterProperty(ZkStateReader.SAMPLE_PERCENTAGE, "100.0")
+        .process(cluster.getSolrClient());
+    try {
+      TimeOut timeOut = new TimeOut(2, TimeUnit.MINUTES, TimeSource.NANO_TIME);
+      timeOut.waitFor("Waiting for GlobalTracer is registered", () -> GlobalTracer.getTracer() instanceof io.jaegertracing.internal.JaegerTracer);
+    } finally {
+      cluster.shutdown();
+    }
+
+  }
+
+  //TODO add integration test with Jaeger run on a container
+
+  @Test
+  public void testRequiredParameters() throws IOException {
+    JaegerTracerConfigurator configurator = new JaegerTracerConfigurator();
+    NamedList initArgs = new NamedList();
+    IllegalArgumentException exc = expectThrows(IllegalArgumentException.class, () -> configurator.init(initArgs));
+    assertTrue(exc.getMessage().contains(AGENT_HOST) || exc.getMessage().contains(AGENT_PORT));
+    initArgs.add(AGENT_HOST, "localhost");
+
+    exc = expectThrows(IllegalArgumentException.class, () -> configurator.init(initArgs));
+    assertTrue(exc.getMessage().contains(AGENT_PORT));
+    initArgs.add(AGENT_PORT, 5775);
+
+    // no exception should be thrown
+    configurator.init(initArgs);
+    ((Closeable)configurator.getTracer()).close();
+
+    initArgs.add(LOG_SPANS, true);
+    initArgs.add(FLUSH_INTERVAL, 1000);
+    initArgs.add(MAX_QUEUE_SIZE, 10000);
+    configurator.init(initArgs);
+    ((Closeable)configurator.getTracer()).close();
+  }
+
+  @Test
+  public void testIncorrectFormat() {
+    JaegerTracerConfigurator configurator = new JaegerTracerConfigurator();
+    NamedList initArgs = new NamedList();
+    initArgs.add(AGENT_HOST, 100);
+    initArgs.add(AGENT_PORT, 5775);
+
+    IllegalArgumentException exc = expectThrows(IllegalArgumentException.class, () -> configurator.init(initArgs));
+    assertTrue(exc.getMessage().contains(AGENT_HOST));
+
+    initArgs.clear();
+    initArgs.add(AGENT_HOST, "localhost");
+    initArgs.add(AGENT_PORT, "5775");
+    exc = expectThrows(IllegalArgumentException.class, () -> configurator.init(initArgs));
+    assertTrue(exc.getMessage().contains(AGENT_PORT));
+
+    initArgs.clear();
+    initArgs.add(AGENT_HOST, "localhost");
+    initArgs.add(AGENT_PORT, 5775);
+    initArgs.add(LOG_SPANS, 10);
+    SolrException solrExc = expectThrows(SolrException.class, () -> configurator.init(initArgs));
+    assertTrue(solrExc.getMessage().contains(LOG_SPANS));
+
+    initArgs.clear();
+    initArgs.add(AGENT_HOST, "localhost");
+    initArgs.add(AGENT_PORT, 5775);
+    initArgs.add(FLUSH_INTERVAL, "10");
+    exc = expectThrows(IllegalArgumentException.class, () -> configurator.init(initArgs));
+    assertTrue(exc.getMessage().contains(FLUSH_INTERVAL));
+
+    initArgs.clear();
+    initArgs.add(AGENT_HOST, "localhost");
+    initArgs.add(AGENT_PORT, 5775);
+    initArgs.add(MAX_QUEUE_SIZE, "10");
+    exc = expectThrows(IllegalArgumentException.class, () -> configurator.init(initArgs));
+    assertTrue(exc.getMessage().contains(MAX_QUEUE_SIZE));
+
+  }
+}

solr/core/ivy.xml

@@ -30,6 +30,10 @@
   </configurations>
 
   <dependencies>
+    <dependency org="io.opentracing" name="opentracing-api" rev="${/io.opentracing/opentracing-api}" conf="compile"/>
+    <dependency org="io.opentracing" name="opentracing-noop" rev="${/io.opentracing/opentracing-noop}" conf="compile"/>
+    <dependency org="io.opentracing" name="opentracing-util" rev="${/io.opentracing/opentracing-util}" conf="compile"/>
+
     <dependency org="commons-codec" name="commons-codec" rev="${/commons-codec/commons-codec}" conf="compile"/>
     <dependency org="commons-io" name="commons-io" rev="${/commons-io/commons-io}" conf="compile"/>
     <dependency org="org.apache.commons" name="commons-exec" rev="${/org.apache.commons/commons-exec}" conf="compile"/>

solr/core/src/java/org/apache/solr/core/CoreContainer.java

@@ -617,8 +617,11 @@ public class CoreContainer {
     hostName = cfg.getNodeName();
 
     zkSys.initZooKeeper(this, solrHome, cfg.getCloudConfig());
-    if(isZooKeeperAware())  pkiAuthenticationPlugin = new PKIAuthenticationPlugin(this, zkSys.getZkController().getNodeName(),
+    if(isZooKeeperAware())  {
-        (PublicKeyHandler) containerHandlers.get(PublicKeyHandler.PATH));
+      pkiAuthenticationPlugin = new PKIAuthenticationPlugin(this, zkSys.getZkController().getNodeName(),
+          (PublicKeyHandler) containerHandlers.get(PublicKeyHandler.PATH));
+      TracerConfigurator.loadTracer(loader, cfg.getTracerConfiguratorPluginInfo(), getZkController().getZkStateReader());
+    }
 
     MDCLoggingContext.setNode(this);
 

solr/core/src/java/org/apache/solr/core/NodeConfig.java

@@ -77,6 +77,8 @@ public class NodeConfig {
 
   private final PluginInfo transientCacheConfig;
 
+  private final PluginInfo tracerConfig;
+
   private NodeConfig(String nodeName, Path coreRootDirectory, Path solrDataHome, Integer booleanQueryMaxClauseCount,
                      Path configSetBaseDirectory, String sharedLibDirectory,
                      PluginInfo shardHandlerFactoryConfig, UpdateShardHandlerConfig updateShardHandlerConfig,
@@ -85,7 +87,7 @@ public class NodeConfig {
                      LogWatcherConfig logWatcherConfig, CloudConfig cloudConfig, Integer coreLoadThreads, int replayUpdatesThreads,
                      int transientCacheSize, boolean useSchemaCache, String managementPath, SolrResourceLoader loader,
                      Properties solrProperties, PluginInfo[] backupRepositoryPlugins,
-                     MetricsConfig metricsConfig, PluginInfo transientCacheConfig) {
+                     MetricsConfig metricsConfig, PluginInfo transientCacheConfig, PluginInfo tracerConfig) {
     this.nodeName = nodeName;
     this.coreRootDirectory = coreRootDirectory;
     this.solrDataHome = solrDataHome;
@@ -111,6 +113,7 @@ public class NodeConfig {
     this.backupRepositoryPlugins = backupRepositoryPlugins;
     this.metricsConfig = metricsConfig;
     this.transientCacheConfig = transientCacheConfig;
+    this.tracerConfig = tracerConfig;
 
     if (this.cloudConfig != null && this.getCoreLoadThreadCount(false) < 2) {
       throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
@@ -226,6 +229,10 @@ public class NodeConfig {
 
   public PluginInfo getTransientCachePluginInfo() { return transientCacheConfig; }
 
+  public PluginInfo getTracerConfiguratorPluginInfo() {
+    return tracerConfig;
+  }
+
   public static class NodeConfigBuilder {
 
     private Path coreRootDirectory;
@@ -253,6 +260,7 @@ public class NodeConfig {
     private PluginInfo[] backupRepositoryPlugins;
     private MetricsConfig metricsConfig;
     private PluginInfo transientCacheConfig;
+    private PluginInfo tracerConfig;
 
     private final SolrResourceLoader loader;
     private final String nodeName;
@@ -410,12 +418,17 @@ public class NodeConfig {
       return this;
     }
 
+    public NodeConfigBuilder setTracerConfig(PluginInfo tracerConfig) {
+      this.tracerConfig = tracerConfig;
+      return this;
+    }
+
     public NodeConfig build() {
       return new NodeConfig(nodeName, coreRootDirectory, solrDataHome, booleanQueryMaxClauseCount,
                             configSetBaseDirectory, sharedLibDirectory, shardHandlerFactoryConfig,
                             updateShardHandlerConfig, coreAdminHandlerClass, collectionsAdminHandlerClass, healthCheckHandlerClass, infoHandlerClass, configSetsHandlerClass,
                             logWatcherConfig, cloudConfig, coreLoadThreads, replayUpdatesThreads, transientCacheSize, useSchemaCache, managementPath, loader, solrProperties,
-                            backupRepositoryPlugins, metricsConfig, transientCacheConfig);
+                            backupRepositoryPlugins, metricsConfig, transientCacheConfig, tracerConfig);
     }
   }
 }

solr/core/src/java/org/apache/solr/core/SolrXmlConfig.java

@@ -100,6 +100,7 @@ public class SolrXmlConfig {
     configBuilder.setUpdateShardHandlerConfig(updateConfig);
     configBuilder.setShardHandlerFactoryConfig(getShardHandlerFactoryPluginInfo(config));
     configBuilder.setSolrCoreCacheFactoryConfig(getTransientCoreCacheFactoryPluginInfo(config));
+    configBuilder.setTracerConfig(getTracerPluginInfo(config));
     configBuilder.setLogWatcherConfig(loadLogWatcherConfig(config, "solr/logging/*[@name]", "solr/logging/watcher/*[@name]"));
     configBuilder.setSolrProperties(loadProperties(config));
     if (cloudConfig != null)
@@ -553,4 +554,9 @@ public class SolrXmlConfig {
     Node node = config.getNode("solr/transientCoreCacheFactory", false);
     return (node == null) ? null : new PluginInfo(node, "transientCoreCacheFactory", false, true);
   }
+
+  private static PluginInfo getTracerPluginInfo(XmlConfigFile config) {
+    Node node = config.getNode("solr/tracerConfig", false);
+    return (node == null) ? null : new PluginInfo(node, "tracerConfig", false, true);
+  }
 }

solr/core/src/java/org/apache/solr/core/TracerConfigurator.java

@@ -0,0 +1,70 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.core;
+
+import java.lang.invoke.MethodHandles;
+
+import io.opentracing.Tracer;
+import io.opentracing.noop.NoopTracerFactory;
+import org.apache.solr.common.cloud.ZkStateReader;
+import org.apache.solr.util.plugin.NamedListInitializedPlugin;
+import org.apache.solr.util.tracing.GlobalTracer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public abstract class TracerConfigurator implements NamedListInitializedPlugin {
+  private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
+
+  public abstract Tracer getTracer();
+
+  public static void loadTracer(SolrResourceLoader loader, PluginInfo info, ZkStateReader stateReader) {
+    if (info == null) {
+      // in case of a Tracer is registered to OpenTracing through javaagent
+      if (io.opentracing.util.GlobalTracer.isRegistered()) {
+        GlobalTracer.setup(io.opentracing.util.GlobalTracer.get());
+        registerListener(stateReader);
+      } else {
+        GlobalTracer.setup(NoopTracerFactory.create());
+        GlobalTracer.get().setSamplePercentage(0.0);
+      }
+    } else {
+      TracerConfigurator configurator = loader
+          .newInstance(info.className, TracerConfigurator.class);
+      configurator.init(info.initArgs);
+
+      GlobalTracer.setup(configurator.getTracer());
+      registerListener(stateReader);
+    }
+  }
+
+  private static void registerListener(ZkStateReader stateReader) {
+    stateReader.registerClusterPropertiesListener(properties -> {
+      if (properties.containsKey(ZkStateReader.SAMPLE_PERCENTAGE)) {
+        try {
+          double sampleRate = Double.parseDouble(properties.get(ZkStateReader.SAMPLE_PERCENTAGE).toString());
+          GlobalTracer.get().setSamplePercentage(sampleRate);
+        } catch (NumberFormatException e) {
+          log.error("Unable to set sample rate", e);
+        }
+      } else {
+        GlobalTracer.get().setSamplePercentage(0.1);
+      }
+      return false;
+    });
+  }
+}

solr/core/src/java/org/apache/solr/handler/component/HttpShardHandler.java

@@ -33,6 +33,10 @@ import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Predicate;
+
+import io.opentracing.Span;
+import io.opentracing.Tracer;
+import io.opentracing.propagation.Format;
 import org.apache.solr.client.solrj.SolrRequest;
 import org.apache.solr.client.solrj.SolrResponse;
 import org.apache.solr.client.solrj.SolrServerException;
@@ -60,6 +64,8 @@ import org.apache.solr.common.util.StrUtils;
 import org.apache.solr.core.CoreDescriptor;
 import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.request.SolrRequestInfo;
+import org.apache.solr.util.tracing.GlobalTracer;
+import org.apache.solr.util.tracing.SolrRequestCarrier;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.slf4j.MDC;
@@ -147,6 +153,8 @@ public class HttpShardHandler extends ShardHandler {
   public void submit(final ShardRequest sreq, final String shard, final ModifiableSolrParams params) {
     // do this outside of the callable for thread safety reasons
     final List<String> urls = getURLs(shard);
+    final Tracer tracer = GlobalTracer.getTracer();
+    final Span span = tracer != null? tracer.activeSpan() : null;
 
     Callable<ShardResponse> task = () -> {
 
@@ -165,6 +173,9 @@ public class HttpShardHandler extends ShardHandler {
         params.remove(CommonParams.VERSION);
 
         QueryRequest req = makeQueryRequest(sreq, params, shard);
+        if (tracer != null && span != null) {
+          tracer.inject(span.context(), Format.Builtin.HTTP_HEADERS, new SolrRequestCarrier(req));
+        }
         req.setMethod(SolrRequest.METHOD.POST);
         SolrRequestInfo requestInfo = SolrRequestInfo.getRequestInfo();
         if (requestInfo != null) req.setUserPrincipal(requestInfo.getReq().getUserPrincipal());

solr/core/src/java/org/apache/solr/logging/MDCLoggingContext.java

@@ -26,6 +26,7 @@ import java.util.function.Supplier;
 
 import org.apache.solr.cloud.CloudDescriptor;
 import org.apache.solr.cloud.ZkController;
+import org.apache.solr.common.StringUtils;
 import org.apache.solr.core.CoreContainer;
 import org.apache.solr.core.CoreDescriptor;
 import org.apache.solr.core.SolrCore;
@@ -37,6 +38,7 @@ import org.slf4j.MDC;
  * {@link #setCoreDescriptor(CoreContainer, CoreDescriptor)} and then {@link #clear()} in a finally block.
  */
 public class MDCLoggingContext {
+  public static final String TRACE_ID = "trace_id";
   // When a thread sets context and finds that the context is already set, we should noop and ignore the finally clear
   private static ThreadLocal<Integer> CALL_DEPTH = ThreadLocal.withInitial(new Supplier<Integer>() {
     @Override
@@ -52,6 +54,14 @@ public class MDCLoggingContext {
       MDC.remove(COLLECTION_PROP);
     }
   }
+
+  public static void setTracerId(String traceId) {
+    if (!StringUtils.isEmpty(traceId)) {
+      MDC.put(TRACE_ID, "t:" + traceId);
+    } else {
+      MDC.remove(TRACE_ID);
+    }
+  }
   
   public static void setShard(String shard) {
     if (shard != null) {
@@ -151,6 +161,7 @@ public class MDCLoggingContext {
     MDC.remove(REPLICA_PROP);
     MDC.remove(SHARD_ID_PROP);
     MDC.remove(NODE_NAME_PROP);
+    MDC.remove(TRACE_ID);
   }
   
   public static void reset() {

solr/core/src/java/org/apache/solr/servlet/HttpSolrCall.java

@@ -38,6 +38,7 @@ import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
+import io.opentracing.Span;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.http.Header;
@@ -106,6 +107,7 @@ import org.apache.solr.servlet.cache.Method;
 import org.apache.solr.update.processor.DistributingUpdateProcessorFactory;
 import org.apache.solr.util.RTimerTree;
 import org.apache.solr.util.TimeOut;
+import org.apache.solr.util.tracing.GlobalTracer;
 import org.apache.zookeeper.KeeperException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -467,6 +469,11 @@ public class HttpSolrCall {
    */
   public Action call() throws IOException {
     MDCLoggingContext.reset();
+    Span activeSpan = GlobalTracer.getTracer().activeSpan();
+    if (activeSpan != null) {
+      MDCLoggingContext.setTracerId(activeSpan.context().toTraceId());
+    }
+
     MDCLoggingContext.setNode(cores);
 
     if (cores == null) {

solr/core/src/java/org/apache/solr/servlet/SolrDispatchFilter.java

@@ -53,6 +53,11 @@ import com.codahale.metrics.jvm.ClassLoadingGaugeSet;
 import com.codahale.metrics.jvm.GarbageCollectorMetricSet;
 import com.codahale.metrics.jvm.MemoryUsageGaugeSet;
 import com.codahale.metrics.jvm.ThreadStatesGaugeSet;
+import io.opentracing.Scope;
+import io.opentracing.Span;
+import io.opentracing.SpanContext;
+import io.opentracing.Tracer;
+import io.opentracing.tag.Tags;
 import org.apache.commons.io.FileCleaningTracker;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.http.client.HttpClient;
@@ -77,6 +82,7 @@ import org.apache.solr.security.AuthenticationPlugin;
 import org.apache.solr.security.PKIAuthenticationPlugin;
 import org.apache.solr.security.PublicKeyHandler;
 import org.apache.solr.util.SolrFileCleaningTracker;
+import org.apache.solr.util.tracing.GlobalTracer;
 import org.apache.solr.util.StartupLoggingUtils;
 import org.apache.solr.util.configuration.SSLConfigurationsFactory;
 import org.slf4j.Logger;
@@ -335,6 +341,7 @@ public class SolrDispatchFilter extends BaseSolrFilter {
         httpClient = null;
         cc.shutdown();
       }
+      GlobalTracer.get().close();
     }
   }
   
@@ -347,7 +354,8 @@ public class SolrDispatchFilter extends BaseSolrFilter {
     if (!(_request instanceof HttpServletRequest)) return;
     HttpServletRequest request = closeShield((HttpServletRequest)_request, retry);
     HttpServletResponse response = closeShield((HttpServletResponse)_response, retry);
-    
+    Scope scope = null;
+    Span span = null;
     try {
 
       if (cores == null || cores.isShutDown()) {
@@ -362,9 +370,9 @@ public class SolrDispatchFilter extends BaseSolrFilter {
         }
       }
 
+      String requestPath = request.getServletPath();
       // No need to even create the HttpSolrCall object if this path is excluded.
       if (excludePatterns != null) {
-        String requestPath = request.getServletPath();
         String extraPath = request.getPathInfo();
         if (extraPath != null) {
           // In embedded mode, servlet path is empty - include all post-context path here for testing
@@ -379,6 +387,24 @@ public class SolrDispatchFilter extends BaseSolrFilter {
         }
       }
 
+      SpanContext parentSpan = GlobalTracer.get().extract(request);
+      Tracer tracer = GlobalTracer.getTracer();
+
+      Tracer.SpanBuilder spanBuilder = null;
+      String hostAndPort = request.getServerName() + "_" + request.getServerPort();
+      if (parentSpan == null) {
+        spanBuilder = tracer.buildSpan(request.getMethod() + ":" + hostAndPort);
+      } else {
+        spanBuilder = tracer.buildSpan(request.getMethod() + ":" + hostAndPort)
+            .asChildOf(parentSpan);
+      }
+
+      spanBuilder
+          .withTag(Tags.SPAN_KIND.getKey(), Tags.SPAN_KIND_SERVER)
+          .withTag(Tags.HTTP_URL.getKey(), request.getRequestURL().toString());
+      span = spanBuilder.start();
+      scope = tracer.scopeManager().activate(span);
+
       AtomicReference<HttpServletRequest> wrappedRequest = new AtomicReference<>();
       if (!authenticateRequest(request, response, wrappedRequest)) { // the response and status code have already been sent
         return;
@@ -416,6 +442,10 @@ public class SolrDispatchFilter extends BaseSolrFilter {
         ExecutorUtil.setServerThreadFlag(null);
       }
     } finally {
+      if (span != null) span.finish();
+      if (scope != null) scope.close();
+
+      GlobalTracer.get().clearContext();
       consumeInputFully(request);
     }
   }

solr/core/src/java/org/apache/solr/servlet/SolrRequestParsers.java

@@ -61,6 +61,7 @@ import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.request.SolrQueryRequestBase;
 import org.apache.solr.util.RTimerTree;
 import org.apache.solr.util.SolrFileCleaningTracker;
+import org.apache.solr.util.tracing.GlobalTracer;
 
 import static org.apache.solr.common.params.CommonParams.PATH;
 
@@ -165,6 +166,9 @@ public class SolrRequestParsers
     // Pick the parser from the request...
     ArrayList<ContentStream> streams = new ArrayList<>(1);
     SolrParams params = parser.parseParamsAndFillStreams( req, streams );
+    if (GlobalTracer.get().tracing()) {
+      GlobalTracer.get().getTracer().activeSpan().setTag("params", params.toString());
+    }
     SolrQueryRequest sreq = buildRequestFrom(core, params, streams, getRequestTimer(req), req);
 
     // Handlers and login will want to know the path. If it contains a ':'

solr/core/src/java/org/apache/solr/update/SolrCmdDistributor.java

@@ -33,6 +33,9 @@ import java.util.concurrent.CompletionService;
 import java.util.concurrent.ExecutorCompletionService;
 import java.util.concurrent.Future;
 
+import io.opentracing.Span;
+import io.opentracing.Tracer;
+import io.opentracing.propagation.Format;
 import org.apache.http.NoHttpResponseException;
 import org.apache.solr.client.solrj.SolrClient;
 import org.apache.solr.client.solrj.SolrServerException;
@@ -50,6 +53,8 @@ import org.apache.solr.request.SolrRequestInfo;
 import org.apache.solr.update.processor.DistributedUpdateProcessor;
 import org.apache.solr.update.processor.DistributedUpdateProcessor.LeaderRequestReplicationTracker;
 import org.apache.solr.update.processor.DistributedUpdateProcessor.RollupRequestReplicationTracker;
+import org.apache.solr.util.tracing.GlobalTracer;
+import org.apache.solr.util.tracing.SolrRequestCarrier;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -285,6 +290,13 @@ public class SolrCmdDistributor implements Closeable {
       req.uReq.setUserPrincipal(SolrRequestInfo.getRequestInfo().getReq().getUserPrincipal());
     }
 
+    Tracer tracer = GlobalTracer.getTracer();
+    Span parentSpan = tracer.activeSpan();
+    if (parentSpan != null) {
+      tracer.inject(parentSpan.context(), Format.Builtin.HTTP_HEADERS,
+          new SolrRequestCarrier(req.uReq));
+    }
+
     if (req.synchronous) {
       blockAndDoRetries();
 

solr/core/src/java/org/apache/solr/util/tracing/GlobalTracer.java

@@ -0,0 +1,120 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.util.tracing;
+
+import javax.servlet.http.HttpServletRequest;
+import java.util.Random;
+
+import com.google.common.annotations.VisibleForTesting;
+import io.opentracing.SpanContext;
+import io.opentracing.Tracer;
+import io.opentracing.noop.NoopTracerFactory;
+import io.opentracing.propagation.Format;
+
+public class GlobalTracer {
+  private static final Tracer NOOP_TRACER = NoopTracerFactory.create();
+  private static final Random RANDOM;
+  static {
+    // We try to make things reproducible in the context of our tests by initializing the random instance
+    // based on the current seed
+    String seed = System.getProperty("tests.seed");
+    if (seed == null) {
+      RANDOM = new Random();
+    } else {
+      RANDOM = new Random(seed.hashCode());
+    }
+  }
+
+  private static volatile GlobalTracer INS = new GlobalTracer(NOOP_TRACER);
+
+  public synchronized static void setup(Tracer tracer) {
+    if (INS != null) {
+      INS.close();
+    }
+    INS = new GlobalTracer(tracer);
+  }
+
+  public static GlobalTracer get() {
+    return INS;
+  }
+
+  public static Tracer getTracer() {
+    return INS.tracer();
+  }
+
+  @VisibleForTesting
+  final Tracer tracer;
+  private double rate;
+  private final ThreadLocal<Tracer> threadLocal = new ThreadLocal<>();
+
+  public GlobalTracer(Tracer tracer) {
+    this.tracer = tracer;
+  }
+
+  public synchronized void setSamplePercentage(double rate) {
+    this.rate = rate / 100.0;
+  }
+
+  @VisibleForTesting
+  public double getSampleRate() {
+    return rate;
+  }
+
+  public boolean tracing() {
+    return threadLocal.get() != null
+        && threadLocal.get() != NOOP_TRACER
+        && threadLocal.get().activeSpan() != null;
+  }
+
+  public SpanContext extract(HttpServletRequest request) {
+    SpanContext spanContext = tracer.extract(Format.Builtin.HTTP_HEADERS, new HttpServletCarrier(request));
+    if (spanContext != null) {
+      threadLocal.set(tracer);
+    }
+    return spanContext;
+  }
+
+  private Tracer tracer() {
+    Tracer tracer = threadLocal.get();
+    if (tracer != null)
+      return tracer;
+
+    if (traced()) {
+      threadLocal.set(this.tracer);
+    } else {
+      threadLocal.set(NOOP_TRACER);
+    }
+
+    return threadLocal.get();
+  }
+
+  /**
+   * Clear tracing context for the current thread
+   */
+  public void clearContext() {
+    threadLocal.remove();
+  }
+
+  private boolean traced() {
+    return RANDOM.nextDouble() <= rate;
+  }
+
+  public void close() {
+    tracer.close();
+  }
+}

solr/core/src/java/org/apache/solr/util/tracing/HttpServletCarrier.java

@@ -0,0 +1,93 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.util.tracing;
+
+import javax.servlet.http.HttpServletRequest;
+import java.util.Enumeration;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.NoSuchElementException;
+
+import io.opentracing.propagation.TextMap;
+
+/**
+ * A Carrier for extract Span context out of request headers
+ */
+public class HttpServletCarrier implements TextMap {
+  private Iterator<Map.Entry<String, String>> it;
+
+  public HttpServletCarrier(HttpServletRequest request) {
+    this.it = new Iterator<>() {
+
+      Enumeration<String> headerNameIt = request.getHeaderNames();
+      String headerName = null;
+      Enumeration<String> headerValue = null;
+
+      @Override
+      public boolean hasNext() {
+        if (headerValue != null && headerValue.hasMoreElements()) {
+          return true;
+        }
+
+        return headerNameIt.hasMoreElements();
+      }
+
+      @Override
+      public Map.Entry<String, String> next() {
+        if (!hasNext()) {
+          throw new NoSuchElementException();
+        }
+
+        if (headerValue == null || !headerValue.hasMoreElements()) {
+          headerName = headerNameIt.nextElement();
+          headerValue = request.getHeaders(headerName);
+        }
+
+        String key = headerName;
+        String val = headerValue.nextElement();
+
+        return new Map.Entry<>() {
+          @Override
+          public String getKey() {
+            return key;
+          }
+
+          @Override
+          public String getValue() {
+            return val;
+          }
+
+          @Override
+          public String setValue(String value) {
+            throw new UnsupportedOperationException();
+          }
+        };
+      }
+    };
+  }
+
+  @Override
+  public Iterator<Map.Entry<String, String>> iterator() {
+    return it;
+  }
+
+  @Override
+  public void put(String key, String value) {
+    throw new UnsupportedOperationException("HttpServletCarrier should only be used with Tracer.extract()");
+  }
+}

solr/core/src/java/org/apache/solr/util/tracing/SolrRequestCarrier.java

@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.util.tracing;
+
+import java.util.Iterator;
+import java.util.Map;
+
+import io.opentracing.propagation.TextMap;
+import org.apache.solr.client.solrj.SolrRequest;
+
+/**
+ * An OpenTracing Carrier for injecting Span context through SolrRequest
+ */
+public class SolrRequestCarrier implements TextMap {
+
+  private final SolrRequest solrRequest;
+
+  public SolrRequestCarrier(SolrRequest solrRequest) {
+    this.solrRequest = solrRequest;
+  }
+
+  @Override
+  public Iterator<Map.Entry<String, String>> iterator() {
+    throw new UnsupportedOperationException("carrier is write-only");
+  }
+
+  @Override
+  public void put(String key, String value) {
+    solrRequest.addHeader(key, value);
+  }
+}

solr/core/src/java/org/apache/solr/util/tracing/package-info.java

@@ -0,0 +1,23 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Tracing related utilities
+ */
+package org.apache.solr.util.tracing;
+
+

solr/core/src/test-files/log4j2.xml

@@ -21,7 +21,7 @@
     <Console name="STDERR" target="SYSTEM_ERR">
       <PatternLayout>
         <Pattern>
-          %maxLen{%-4r %-5p (%t) [%X{node_name} %X{collection} %X{shard} %X{replica} %X{core}] %c{1.} %m%notEmpty{
+          %maxLen{%-4r %-5p (%t) [%X{node_name} %X{collection} %X{shard} %X{replica} %X{core} %X{trace_id}] %c{1.} %m%notEmpty{
           =>%ex{short}}}{10240}%n
         </Pattern>
       </PatternLayout>

solr/core/src/test-files/solr/solr-tracing.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements.  See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ (the "License"); you may not use this file except in compliance with
+ the License.  You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+-->
+
+<!--
+ All (relative) paths are relative to the installation path
+-->
+<solr>
+
+  <str name="shareSchema">${shareSchema:false}</str>
+  <str name="configSetBaseDir">${configSetBaseDir:configsets}</str>
+  <str name="coreRootDirectory">${coreRootDirectory:.}</str>
+  <str name="collectionsHandler">${collectionsHandler:solr.CollectionsHandler}</str>
+
+  <shardHandlerFactory name="shardHandlerFactory" class="HttpShardHandlerFactory">
+    <str name="urlScheme">${urlScheme:}</str>
+    <int name="socketTimeout">${socketTimeout:90000}</int>
+    <int name="connTimeout">${connTimeout:15000}</int>
+    <str name="shardsWhitelist">${solr.tests.shardsWhitelist:}</str>
+  </shardHandlerFactory>
+
+  <tracerConfig name="tracerConfig" class="MockTracerConfigurator">
+  </tracerConfig>
+
+  <solrcloud>
+    <str name="host">127.0.0.1</str>
+    <int name="hostPort">${hostPort:8983}</int>
+    <str name="hostContext">${hostContext:solr}</str>
+    <int name="zkClientTimeout">${solr.zkclienttimeout:30000}</int>
+    <bool name="genericCoreNodeNames">${genericCoreNodeNames:true}</bool>
+    <int name="leaderVoteWait">${leaderVoteWait:10000}</int>
+    <int name="distribUpdateConnTimeout">${distribUpdateConnTimeout:45000}</int>
+    <int name="distribUpdateSoTimeout">${distribUpdateSoTimeout:340000}</int>
+    <str name="zkCredentialsProvider">${zkCredentialsProvider:org.apache.solr.common.cloud.DefaultZkCredentialsProvider}</str>
+    <str name="zkACLProvider">${zkACLProvider:org.apache.solr.common.cloud.DefaultZkACLProvider}</str>
+  </solrcloud>
+  <metrics>
+    <reporter name="default" class="org.apache.solr.metrics.reporters.SolrJmxReporter">
+      <str name="rootName">solr_${hostPort:8983}</str>
+    </reporter>
+  </metrics>
+
+</solr>

solr/core/src/test/org/apache/solr/security/JWTAuthPluginIntegrationTest.java

@@ -173,23 +173,23 @@ public class JWTAuthPluginIntegrationTest extends SolrCloudAuthTestCase {
     assertPkiAuthMetricsMinimums(4, 4, 0, 0, 0, 0);
     Pair<String,Integer> result = post(baseUrl + "/" + COLLECTION + "/update?commit=true", "[{\"id\" : \"1\"}, {\"id\": \"2\"}, {\"id\": \"3\"}]", jwtTestToken);
     assertEquals(Integer.valueOf(200), result.second());
-    assertAuthMetricsMinimums(3, 3, 0, 0, 0, 0);
+    assertAuthMetricsMinimums(4, 4, 0, 0, 0, 0);
-    assertPkiAuthMetricsMinimums(5, 5, 0, 0, 0, 0);
+    assertPkiAuthMetricsMinimums(4, 4, 0, 0, 0, 0);
     
     // First a non distributed query
     result = get(baseUrl + "/" + COLLECTION + "/query?q=*:*&distrib=false", jwtTestToken);
     assertEquals(Integer.valueOf(200), result.second());
-    assertAuthMetricsMinimums(4, 4, 0, 0, 0, 0);
+    assertAuthMetricsMinimums(5, 5, 0, 0, 0, 0);
 
     // Now do a distributed query, using JWTAuth for inter-node
     result = get(baseUrl + "/" + COLLECTION + "/query?q=*:*", jwtTestToken);
     assertEquals(Integer.valueOf(200), result.second());
-    assertAuthMetricsMinimums(9, 9, 0, 0, 0, 0);
+    assertAuthMetricsMinimums(10, 10, 0, 0, 0, 0);
     
     // Delete
     assertEquals(200, get(baseUrl + "/admin/collections?action=DELETE&name=" + COLLECTION, jwtTestToken).second().intValue());
-    assertAuthMetricsMinimums(10, 10, 0, 0, 0, 0);
+    assertAuthMetricsMinimums(11, 11, 0, 0, 0, 0);
-    assertPkiAuthMetricsMinimums(7, 7, 0, 0, 0, 0);
+    assertPkiAuthMetricsMinimums(6, 6, 0, 0, 0, 0);
   }
 
   private void getAndFail(String url, String token) {

solr/core/src/test/org/apache/solr/util/tracing/TestDistributedTracing.java

@@ -0,0 +1,144 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.util.tracing;
+
+import java.io.IOException;
+import java.lang.invoke.MethodHandles;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.stream.Collectors;
+
+import io.opentracing.mock.MockSpan;
+import io.opentracing.mock.MockTracer;
+import org.apache.solr.client.solrj.SolrQuery;
+import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.client.solrj.impl.CloudSolrClient;
+import org.apache.solr.client.solrj.request.CollectionAdminRequest;
+import org.apache.solr.cloud.SolrCloudTestCase;
+import org.apache.solr.common.cloud.ZkStateReader;
+import org.apache.solr.common.util.TimeSource;
+import org.apache.solr.util.TimeOut;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+
+public class TestDistributedTracing extends SolrCloudTestCase {
+  private static final String COLLECTION = "collection1";
+  private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
+
+  @BeforeClass
+  public static void beforeTest() throws Exception {
+    configureCluster(4)
+        .addConfig("config", TEST_PATH().resolve("configsets").resolve("cloud-minimal").resolve("conf"))
+        .withSolrXml(TEST_PATH().resolve("solr-tracing.xml"))
+        .configure();
+    CollectionAdminRequest.setClusterProperty(ZkStateReader.SAMPLE_PERCENTAGE, "100.0")
+        .process(cluster.getSolrClient());
+    waitForSampleRateUpdated(1.0);
+    CollectionAdminRequest
+        .createCollection(COLLECTION, "config", 2, 2)
+        .process(cluster.getSolrClient());
+    cluster.waitForActiveCollection(COLLECTION, 2, 4);
+  }
+
+  private static void waitForSampleRateUpdated(double rate) throws TimeoutException, InterruptedException {
+    TimeOut timeOut = new TimeOut(1, TimeUnit.MINUTES, TimeSource.NANO_TIME);
+    timeOut.waitFor("Waiting for sample rate is updated", () ->
+        Math.abs(GlobalTracer.get().getSampleRate() - rate) < 0.001
+            && GlobalTracer.get().tracer instanceof MockTracer);
+  }
+
+  private List<MockSpan> getFinishedSpans() {
+    return ((MockTracer)GlobalTracer.get().tracer).finishedSpans();
+  }
+
+  @Test
+  public void test() throws IOException, SolrServerException, TimeoutException, InterruptedException {
+    CloudSolrClient cloudClient = cluster.getSolrClient();
+    List<MockSpan> allSpans = getFinishedSpans();
+
+    cloudClient.add(COLLECTION, sdoc("id", "1"));
+    List<MockSpan> finishedSpans = getRecentSpans(allSpans);
+    finishedSpans.removeIf(x ->
+        !x.tags().get("http.url").toString().endsWith("/update"));
+    assertEquals(2, finishedSpans.size());
+    assertOneSpanIsChildOfAnother(finishedSpans);
+
+    cloudClient.add(COLLECTION, sdoc("id", "2"));
+    finishedSpans = getRecentSpans(allSpans);
+    finishedSpans.removeIf(x ->
+        !x.tags().get("http.url").toString().endsWith("/update"));
+    assertEquals(2, finishedSpans.size());
+    assertOneSpanIsChildOfAnother(finishedSpans);
+
+    cloudClient.add(COLLECTION, sdoc("id", "3"));
+    cloudClient.add(COLLECTION, sdoc("id", "4"));
+    cloudClient.commit(COLLECTION);
+
+    getRecentSpans(allSpans);
+    cloudClient.query(COLLECTION, new SolrQuery("*:*"));
+    finishedSpans = getRecentSpans(allSpans);
+    finishedSpans.removeIf(x ->
+        !x.tags().get("http.url").toString().endsWith("/select"));
+    // one from client to server, 2 for execute query, 2 for fetching documents
+    assertEquals(5, finishedSpans.size());
+    assertEquals(1, finishedSpans.stream().filter(s -> s.parentId() == 0).count());
+    long parentId = finishedSpans.stream()
+        .filter(s -> s.parentId() == 0)
+        .collect(Collectors.toList())
+        .get(0).context().spanId();
+    for (MockSpan span: finishedSpans) {
+      if (span.parentId() != 0 && parentId != span.parentId()) {
+        fail("All spans must belong to single span, but:"+finishedSpans);
+      }
+    }
+
+    CollectionAdminRequest.setClusterProperty(ZkStateReader.SAMPLE_PERCENTAGE, "0.0")
+        .process(cluster.getSolrClient());
+    waitForSampleRateUpdated(0);
+
+    getRecentSpans(allSpans);
+    cloudClient.add(COLLECTION, sdoc("id", "5"));
+    finishedSpans = getRecentSpans(allSpans);
+    assertEquals(0, finishedSpans.size());
+  }
+
+  private void assertOneSpanIsChildOfAnother(List<MockSpan> finishedSpans) {
+    MockSpan child = finishedSpans.get(0);
+    MockSpan parent = finishedSpans.get(1);
+    if (child.parentId() == 0) {
+      MockSpan temp = parent;
+      parent = child;
+      child = temp;
+    }
+
+    assertEquals(child.parentId(), parent.context().spanId());
+  }
+
+  private List<MockSpan> getRecentSpans(List<MockSpan> allSpans) {
+    List<MockSpan> result = new ArrayList<>(getFinishedSpans());
+    result.removeAll(allSpans);
+    allSpans.clear();
+    allSpans.addAll(getFinishedSpans());
+    return result;
+  }
+}

solr/core/src/test/org/apache/solr/util/tracing/TestHttpServletCarrier.java

@@ -0,0 +1,68 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.util.tracing;
+
+import javax.servlet.http.HttpServletRequest;
+
+import java.util.Enumeration;
+import java.util.Iterator;
+import java.util.Map;
+
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.Multimap;
+import org.apache.commons.collections.IteratorUtils;
+import org.apache.solr.SolrTestCaseJ4;
+import org.junit.Test;
+import org.mockito.stubbing.Answer;
+
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TestHttpServletCarrier extends SolrTestCaseJ4 {
+
+  @Test
+  public void test() {
+    SolrTestCaseJ4.assumeWorkingMockito();
+    HttpServletRequest req = mock(HttpServletRequest.class);
+    Multimap<String, String> headers = HashMultimap.create();
+    headers.put("a", "a");
+    headers.put("a", "b");
+    headers.put("a", "c");
+    headers.put("b", "a");
+    headers.put("b", "b");
+    headers.put("c", "a");
+
+    when(req.getHeaderNames()).thenReturn(IteratorUtils.asEnumeration(headers.keySet().iterator()));
+    when(req.getHeaders(anyString())).thenAnswer((Answer<Enumeration<String>>) inv -> {
+      String key = inv.getArgument(0);
+      return IteratorUtils.asEnumeration(headers.get(key).iterator());
+    });
+
+    HttpServletCarrier servletCarrier = new HttpServletCarrier(req);
+    Iterator<Map.Entry<String, String>> it = servletCarrier.iterator();
+    Multimap<String, String> resultBack = HashMultimap.create();
+    while(it.hasNext()) {
+      Map.Entry<String, String> entry = it.next();
+      resultBack.put(entry.getKey(), entry.getValue());
+    }
+    assertEquals(headers, resultBack);
+
+
+  }
+}

solr/licenses/jaeger-core-0.35.5.jar.sha1

@@ -0,0 +1 @@
+fc934c7619ca7c626a7ce713646d8c43f8dca8bd

solr/licenses/jaeger-core-LICENSE-ASL.txt

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

solr/licenses/jaeger-thrift-0.35.5.jar.sha1

@@ -0,0 +1 @@
+dc4066e5b4532121b8e4d69124919376ab123940

solr/licenses/jaeger-thrift-LICENSE-ASL.txt

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

solr/licenses/libthrift-0.12.0.jar.sha1

@@ -0,0 +1 @@
+300bfbee03c7afa77301fb0946115e400e28ae04

solr/licenses/libthrift-LICENSE-ASL.txt

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

solr/licenses/libthrift-NOTICE.txt

@@ -0,0 +1,5 @@
+Apache Thrift
+Copyright (C) 2006 - 2019, The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).

solr/licenses/opentracing-api-0.33.0.jar.sha1

@@ -0,0 +1 @@
+67336cfb9d93779c02e1fda4c87801d352720eda

solr/licenses/opentracing-api-LICENSE-ASL.txt

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

solr/licenses/opentracing-mock-0.33.0.jar.sha1

@@ -0,0 +1 @@
+68f907743a5b355a8e975fdd3df0d2e106bbad6c

solr/licenses/opentracing-mock-LICENSE-ASL.txt

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

solr/licenses/opentracing-noop-0.33.0.jar.sha1

@@ -0,0 +1 @@
+074b9950a587f53fbdb48c3f1f84f1ece8c10592

solr/licenses/opentracing-noop-LICENSE-ASL.txt

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

solr/licenses/opentracing-util-0.33.0.jar.sha1

@@ -0,0 +1 @@
+132630f17e198a1748f23ce33597efdf4a807fb9

solr/licenses/opentracing-util-LICENSE-ASL.txt

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
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+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
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+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
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+      form, that is based on (or derived from) the Work and for which the
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+      of this License, Derivative Works shall not include works that remain
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+
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+      on behalf of whom a Contribution has been received by Licensor and
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+
+   2. Grant of Copyright License. Subject to the terms and conditions of
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+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
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+      meet the following conditions:
+
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+          Derivative Works a copy of this License; and
+
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+
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+          notices within Derivative Works that You distribute, alongside
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+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

solr/solr-ref-guide/src/metrics-reporting.adoc

@@ -265,7 +265,7 @@ Here is an example for configuring the default `log4j2.xml` which ships in Solr.
         filePattern="${sys:solr.log.dir}/solr_metrics.log.%i" >
       <PatternLayout>
         <Pattern>
-          %d{yyyy-MM-dd HH:mm:ss.SSS} %-5p (%t) [%X{node_name} %X{collection} %X{shard} %X{replica} %X{core}] %m%n
+          %d{yyyy-MM-dd HH:mm:ss.SSS} %-5p (%t) [%X{node_name} %X{collection} %X{shard} %X{replica} %X{core} %X{trace_id}] %m%n
         </Pattern>
       </PatternLayout>
       <Policies>

solr/solr-ref-guide/src/monitoring-solr.adoc

@@ -1,5 +1,5 @@
 = Monitoring Solr
-:page-children: metrics-reporting, metrics-history, mbean-request-handler, configuring-logging, using-jmx-with-solr, monitoring-solr-with-prometheus-and-grafana, performance-statistics-reference
+:page-children: metrics-reporting, metrics-history, mbean-request-handler, configuring-logging, using-jmx-with-solr, monitoring-solr-with-prometheus-and-grafana, performance-statistics-reference, solr-tracing
 // Licensed to the Apache Software Foundation (ASF) under one
 // or more contributor license agreements.  See the NOTICE file
 // distributed with this work for additional information
@@ -36,4 +36,6 @@ Common administrative tasks include:
 
 <<performance-statistics-reference.adoc#performance-statistics-reference,Performance Statistics Reference>>: Additional information on statistics returned from JMX.
 
+<<solr-tracing.adoc#solr-tracing,Distributed Solr Tracing>>: Describes how to do distributed tracing for Solr requests.
+
 

solr/solr-ref-guide/src/solr-tracing.adoc

@@ -0,0 +1,87 @@
+= Distributed Solr Tracing
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+Solr includes a general tracing framework based on OpenTracing that can be used to trace lifecycle of a request for performance monitoring.
+Tracing data can be configured and send to arbitrary backend like Jaeger, Zipkin, Datadog, etc. For now only Jaeger is
+supported out of the box.
+
+A sampled distributed tracing query request on Jaeger looks like this:
+
+.Tracing of a solr query
+image::images/solr-tracing/query-request-tracing.png[image,width=600]
+
+== Setup Tracer
+
+`TracerConfigurator` is a class used for provide an instance of `io.opentracing.Tracer` based on configuration in `solr.xml`.
+Like `JaegerTracerConfigurator` provide JaegerTracer instance to Solr node.
+
+A setup of a `TracerConfigurator` looks like this
+
+```xml
+<solr>
+  <tracerConfig name="tracerConfig" class="org.apache.solr.jaeger.JaegerTracerConfigurator">
+    <str name="agentHost">localhost</str>
+    <int name="agentPort">5775</int>
+    <bool name="logSpans">true</bool>
+    <int name="flushInterval">1000</int>
+    <int name="maxQueueSize">10000</int>
+  </tracerConfig>
+</solr>
+```
+
+If `<tracerConfig>` part is absent, `TracerConfigurator` will try to pick up the `Tracer` instance was registered in
+in `io.opentracing.util.GlobalTracer`. By doing this some backend like DataDog is supported out of the box since
+https://docs.datadoghq.com/tracing/setup/java/[datadog-java-agent] use Javaagent to register a `Tracer` in
+`io.opentracing.util.GlobalTracer`.
+
+=== Configuring sample rate
+
+By default only 0.1% of requests are sampled, this ensure that tracing activities does not affect performance of a node.
+
+The rate can be changed on the fly (without restarting Solr nodes) by setting new sample rate in cluster property. For example,
+below call set sample rate to 100%
+```
+/admin/collections?action=CLUSTERPROP&name=propertyName&samplePercentage=100
+```
+
+== Jaeger Tracer Configurator
+
+Module `contrib/jagertracer-configurator` provides a default implementation for setting up Jaeger Tracer.
+Note that all library of jaegertracer-configurator must be included in the classpath of all nodes then Jaeger tracer can be setup in `solr.xml` like this:
+
+```
+<tracerConfig name="tracerConfig" class="org.apache.solr.jaeger.JaegerTracerConfigurator">
+  <str name="agentHost">localhost</str>
+  <int name="agentPort">5775</int>
+  <bool name="logSpans">true</bool>
+  <int name="flushInterval">1000</int>
+  <int name="maxQueueSize">10000</int>
+</tracerConfig>
+```
+
+List of parameters for JaegerTracerConfigurator include:
+|===
+|Parameter|Type|Required|Default|Description
+|agentHost|string|Yes||The host of Jaeger backend
+|agentPort|int|Yes||The port of Jaeger port
+|logsSpans|bool|No|true|Whether the tracer should also log the spans
+|flushInterval|int|No|5000|The tracer's flush interval (ms)
+|maxQueueSize|int|No|10000|The tracer's maximum queue size
+|===
+
+Other parameters which are not listed above can be configured using System Properties or Environment Variables. The full list are listed at https://github.com/jaegertracing/jaeger-client-java/blob/master/jaeger-core/README.md[Jaeger-README].

solr/solrj/src/java/org/apache/solr/client/solrj/SolrRequest.java

@@ -21,7 +21,10 @@ import java.io.Serializable;
 import java.security.Principal;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
@@ -63,6 +66,7 @@ public abstract class SolrRequest<T extends SolrResponse> implements Serializabl
 
   private METHOD method = METHOD.GET;
   private String path = null;
+  private Map<String,String> headers;
 
   private ResponseParser responseParser;
   private StreamingResponseCallback callback;
@@ -237,4 +241,16 @@ public abstract class SolrRequest<T extends SolrResponse> implements Serializabl
   public String getBasePath() {
     return basePath;
   }
+
+  public void addHeader(String key, String value) {
+    if (headers == null) {
+      headers = new HashMap<>();
+    }
+    headers.put(key, value);
+  }
+
+  public Map<String, String> getHeaders() {
+    if (headers == null) return null;
+    return Collections.unmodifiableMap(headers);
+  }
 }

solr/solrj/src/java/org/apache/solr/client/solrj/impl/Http2SolrClient.java

@@ -31,6 +31,7 @@ import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
@@ -317,10 +318,9 @@ public class Http2SolrClient extends SolrClient {
         .newRequest(basePath + "update"
             + requestParams.toQueryString())
         .method(HttpMethod.POST)
-        .header("User-Agent", HttpSolrClient.AGENT)
+        .header(HttpHeader.CONTENT_TYPE, contentType)
-        .header("Content-Type", contentType)
         .content(provider);
-    setListeners(updateRequest, postRequest);
+    decorateRequest(postRequest, updateRequest);
     InputStreamResponseListener responseListener = new InputStreamResponseListener();
     postRequest.send(responseListener);
 
@@ -452,16 +452,16 @@ public class Http2SolrClient extends SolrClient {
   private Request makeRequest(SolrRequest solrRequest, String collection)
       throws SolrServerException, IOException {
     Request req = createRequest(solrRequest, collection);
+    decorateRequest(req, solrRequest);
+    return req;
+  }
+
+  private void decorateRequest(Request req, SolrRequest solrRequest) {
     req.header(HttpHeader.ACCEPT_ENCODING, null);
-    setListeners(solrRequest, req);
     if (solrRequest.getUserPrincipal() != null) {
       req.attribute(REQ_PRINCIPAL_KEY, solrRequest.getUserPrincipal());
     }
 
-    return req;
-  }
-
-  private void setListeners(SolrRequest solrRequest, Request req) {
     setBasicAuthHeader(solrRequest, req);
     for (HttpListenerFactory factory : listenerFactory) {
       HttpListenerFactory.RequestResponseListener listener = factory.get();
@@ -469,6 +469,13 @@ public class Http2SolrClient extends SolrClient {
       req.onRequestBegin(listener);
       req.onComplete(listener);
     }
+
+    Map<String, String> headers = solrRequest.getHeaders();
+    if (headers != null) {
+      for (Map.Entry<String, String> entry : headers.entrySet()) {
+        req.header(entry.getKey(), entry.getValue());
+      }
+    }
   }
 
   private Request createRequest(SolrRequest solrRequest, String collection) throws IOException, SolrServerException {

solr/solrj/src/java/org/apache/solr/client/solrj/impl/HttpSolrClient.java

@@ -32,6 +32,7 @@ import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.ExecutorService;
@@ -252,6 +253,12 @@ public class HttpSolrClient extends BaseHttpSolrClient {
       throws SolrServerException, IOException {
     HttpRequestBase method = createMethod(request, collection);
     setBasicAuthHeader(request, method);
+    if (request.getHeaders() != null) {
+      Map<String, String> headers = request.getHeaders();
+      for (Map.Entry<String, String> entry : headers.entrySet()) {
+        method.setHeader(entry.getKey(), entry.getValue());
+      }
+    }
     return executeMethod(method, request.getUserPrincipal(), processor, isV2ApiRequest(request));
   }
 

solr/solrj/src/java/org/apache/solr/common/cloud/ZkStateReader.java

@@ -133,6 +133,7 @@ public class ZkStateReader implements SolrCloseable {
   public final static String CONFIGNAME_PROP="configName";
 
   public static final String LEGACY_CLOUD = "legacyCloud";
+  public static final String SAMPLE_PERCENTAGE = "samplePercentage";
 
   /**
    * @deprecated use {@link org.apache.solr.common.params.CollectionAdminParams#DEFAULTS} instead.
@@ -246,6 +247,7 @@ public class ZkStateReader implements SolrCloseable {
       CoreAdminParams.BACKUP_LOCATION,
       DEFAULT_SHARD_PREFERENCES,
       MAX_CORES_PER_NODE,
+      SAMPLE_PERCENTAGE,
       CollectionAdminParams.DEFAULTS)));
 
   /**

solr/solrj/src/test-files/log4j2.xml

@@ -21,7 +21,7 @@
     <Console name="STDERR" target="SYSTEM_ERR">
       <PatternLayout>
         <Pattern>
-          %maxLen{%-4r %-5p (%t) [%X{node_name} %X{collection} %X{shard} %X{replica} %X{core}] %c{1.} %m%notEmpty{
+          %maxLen{%-4r %-5p (%t) [%X{node_name} %X{collection} %X{shard} %X{replica} %X{core} %X{trace_id}] %c{1.} %m%notEmpty{
           =>%ex{short}}}{10240}%n
         </Pattern>
       </PatternLayout>

solr/test-framework/ivy.xml

@@ -35,6 +35,7 @@
     <dependency org="org.hamcrest" name="hamcrest-core" rev="${/org.hamcrest/hamcrest-core}" conf="compile;junit4-stdalone" />
     <dependency org="com.carrotsearch.randomizedtesting" name="junit4-ant" rev="${/com.carrotsearch.randomizedtesting/junit4-ant}" conf="compile;junit4-stdalone" />
     <dependency org="com.carrotsearch.randomizedtesting" name="randomizedtesting-runner" rev="${/com.carrotsearch.randomizedtesting/randomizedtesting-runner}" conf="compile;junit4-stdalone" />
+    <dependency org="io.opentracing" name="opentracing-mock" rev="${/io.opentracing/opentracing-mock}" conf="compile;junit4-stdalone"/>
 
     <exclude org="*" ext="*" matcher="regexp" type="${ivy.exclude.types}"/> 
   </dependencies>

solr/test-framework/src/java/org/apache/solr/core/MockTracerConfigurator.java

@@ -0,0 +1,35 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.solr.core;
+
+import io.opentracing.Tracer;
+import io.opentracing.mock.MockTracer;
+import org.apache.solr.common.util.NamedList;
+
+public class MockTracerConfigurator extends TracerConfigurator {
+  
+  @Override
+  public Tracer getTracer() {
+    return new MockTracer();
+  }
+
+  @Override
+  public void init(NamedList args) {
+
+  }
+}