SOLR-13942: /api/cluster/zk/* to fetch raw ZK data

solr/CHANGES.txt

@@ -65,6 +65,8 @@ New Features
  * SOLR-13965: In GraphHandler, support <expressible> configuration and deprecate <streamFunctions> configuration.
    (Eric Pugh via Christine Poerschke)
 
+* SOLR-13942: /api/cluster/zk/* to fetch raw ZK data (noble)
+
 Improvements
 ---------------------
 * SOLR-14120: Define JavaScript methods 'includes' and 'startsWith' to ensure AdminUI can be displayed when using

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

@@ -96,6 +96,7 @@ import org.apache.solr.handler.admin.MetricsHistoryHandler;
 import org.apache.solr.handler.admin.SecurityConfHandler;
 import org.apache.solr.handler.admin.SecurityConfHandlerLocal;
 import org.apache.solr.handler.admin.SecurityConfHandlerZk;
+import org.apache.solr.handler.admin.ZkRead;
 import org.apache.solr.handler.admin.ZookeeperInfoHandler;
 import org.apache.solr.handler.admin.ZookeeperStatusHandler;
 import org.apache.solr.handler.component.ShardHandlerFactory;
@@ -674,6 +675,7 @@ public class CoreContainer {
       packageLoader = new PackageLoader(this);
       containerHandlers.getApiBag().register(new AnnotatedApi(packageLoader.getPackageAPI().editAPI), Collections.EMPTY_MAP);
       containerHandlers.getApiBag().register(new AnnotatedApi(packageLoader.getPackageAPI().readAPI), Collections.EMPTY_MAP);
+      containerHandlers.getApiBag().register(new AnnotatedApi(new ZkRead(this)), Collections.EMPTY_MAP);
     }
 
     MDCLoggingContext.setNode(this);

solr/core/src/java/org/apache/solr/handler/admin/ZkRead.java

@@ -0,0 +1,117 @@
+/*
+ * 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.handler.admin;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.solr.api.Command;
+import org.apache.solr.api.EndPoint;
+import org.apache.solr.client.solrj.SolrRequest;
+import org.apache.solr.client.solrj.impl.BinaryResponseParser;
+import org.apache.solr.common.MapWriter;
+import org.apache.solr.common.params.CommonParams;
+import org.apache.solr.common.params.MapSolrParams;
+import org.apache.solr.common.params.SolrParams;
+import org.apache.solr.common.util.ContentStreamBase;
+import org.apache.solr.common.util.Utils;
+import org.apache.solr.core.CoreContainer;
+import org.apache.solr.request.SolrQueryRequest;
+import org.apache.solr.response.SolrQueryResponse;
+import org.apache.zookeeper.data.Stat;
+
+import static org.apache.solr.common.params.CommonParams.OMIT_HEADER;
+import static org.apache.solr.common.params.CommonParams.WT;
+import static org.apache.solr.response.RawResponseWriter.CONTENT;
+import static org.apache.solr.security.PermissionNameProvider.Name.COLL_READ_PERM;
+
+/**Exposes the content of the Zookeeper
+ *
+ */
+@EndPoint(path = "/cluster/zk/*",
+    method = SolrRequest.METHOD.GET,
+    permission = COLL_READ_PERM)
+public class ZkRead {
+  private final CoreContainer coreContainer;
+
+  public ZkRead(CoreContainer coreContainer) {
+    this.coreContainer = coreContainer;
+  }
+
+  @Command
+  public void get(SolrQueryRequest req, SolrQueryResponse rsp) {
+    String path = req.getPathTemplateValues().get("*");
+    if (path == null || path.isEmpty()) path = "/";
+    byte[] d = null;
+    try {
+      List<String> l = coreContainer.getZkController().getZkClient().getChildren(path, null, false);
+      if (l != null && !l.isEmpty()) {
+        String prefix = path.endsWith("/") ? path : path + "/";
+
+        rsp.add(path, (MapWriter) ew -> {
+          for (String s : l) {
+            try {
+              Stat stat = coreContainer.getZkController().getZkClient().exists(prefix + s, null, false);
+              ew.put(s, (MapWriter) ew1 -> {
+                ew1.put("version", stat.getVersion());
+                ew1.put("aversion", stat.getAversion());
+                ew1.put("children", stat.getNumChildren());
+                ew1.put("ctime", stat.getCtime());
+                ew1.put("cversion", stat.getCversion());
+                ew1.put("czxid", stat.getCzxid());
+                ew1.put("ephemeralOwner", stat.getEphemeralOwner());
+                ew1.put("mtime", stat.getMtime());
+                ew1.put("mzxid", stat.getMzxid());
+                ew1.put("pzxid", stat.getPzxid());
+                ew1.put("dataLength", stat.getDataLength());
+              });
+            } catch (Exception e) {
+              ew.put("s", Collections.singletonMap("error", e.getMessage()));
+            }
+          }
+        });
+
+      } else {
+        d = coreContainer.getZkController().getZkClient().getData(path, null, null, false);
+        if (d == null || d.length == 0) {
+          rsp.add(path, null);
+          return;
+        }
+
+        Map<String, String> map = new HashMap<>(1);
+        map.put(WT, "raw");
+        map.put(OMIT_HEADER, "true");
+        req.setParams(SolrParams.wrapDefaults(new MapSolrParams(map), req.getParams()));
+
+
+        rsp.add(CONTENT, new ContentStreamBase.ByteArrayStream(d, null,
+            d[0] == '{' ? CommonParams.JSON_MIME : BinaryResponseParser.BINARY_CONTENT_TYPE));
+
+      }
+
+    } catch (Exception e) {
+      rsp.add(CONTENT, new ContentStreamBase.StringStream(Utils.toJSONString(Collections.singletonMap("error", e.getMessage()))));
+    }
+  }
+
+  public static void main(String[] args) {
+  }
+
+}

solr/core/src/test/org/apache/solr/handler/admin/ZookeeperStatusHandlerTest.java

@@ -37,6 +37,7 @@ import org.apache.solr.cloud.SolrCloudTestCase;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.params.ModifiableSolrParams;
 import org.apache.solr.common.util.NamedList;
+import org.apache.solr.common.util.Utils;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.BeforeClass;
@@ -74,6 +75,15 @@ public class ZookeeperStatusHandlerTest extends SolrCloudTestCase {
     super.tearDown();
   }
 
+  @Test
+  public void testZkread() throws Exception {
+    URL baseUrl = cluster.getJettySolrRunner(0).getBaseUrl();
+    try(  HttpSolrClient client = new HttpSolrClient.Builder(baseUrl.toString()).build()){
+      Object o = Utils.executeGET(client.getHttpClient(), baseUrl.toString().replace("/solr", "/api"+ "/cluster/zk/security.json"), Utils.JSONCONSUMER );
+      assertNotNull(o);
+    }
+  }
+
   /*
     Test the monitoring endpoint, used in the Cloud => ZkStatus Admin UI screen
     NOTE: We do not currently test with multiple zookeepers, but the only difference is that there are multiple "details" objects and mode is "ensemble"... 
@@ -87,13 +97,13 @@ public class ZookeeperStatusHandlerTest extends SolrCloudTestCase {
     NamedList<Object> nl = solr.httpUriRequest(mntrReq).future.get(10000, TimeUnit.MILLISECONDS);
 
     assertEquals("zkStatus", nl.getName(1));
-    Map<String,Object> zkStatus = (Map<String,Object>) nl.get("zkStatus");
+    Map<String, Object> zkStatus = (Map<String, Object>) nl.get("zkStatus");
     assertEquals("green", zkStatus.get("status"));
     assertEquals("standalone", zkStatus.get("mode"));
     assertEquals(1L, zkStatus.get("ensembleSize"));
-    List<Object> detailsList = (List<Object>)zkStatus.get("details");
+    List<Object> detailsList = (List<Object>) zkStatus.get("details");
     assertEquals(1, detailsList.size());
-    Map<String,Object> details = (Map<String,Object>) detailsList.get(0);
+    Map<String, Object> details = (Map<String, Object>) detailsList.get(0);
     assertEquals(true, details.get("ok"));
     assertTrue(Integer.parseInt((String) details.get("zk_znode_count")) > 50);
     solr.close();
@@ -106,12 +116,12 @@ public class ZookeeperStatusHandlerTest extends SolrCloudTestCase {
     when(zkStatusHandler.getZkRawResponse("zoo1:2181", "ruok")).thenReturn(Arrays.asList("imok"));
     when(zkStatusHandler.getZkRawResponse("zoo1:2181", "mntr")).thenReturn(
         Arrays.asList("zk_version\t3.5.5-390fe37ea45dee01bf87dc1c042b5e3dcce88653, built on 05/03/2019 12:07 GMT",
-        "zk_avg_latency\t1"));
+            "zk_avg_latency\t1"));
     when(zkStatusHandler.getZkRawResponse("zoo1:2181", "conf")).thenReturn(
         Arrays.asList("clientPort=2181",
-        "secureClientPort=-1",
+            "secureClientPort=-1",
-        "thisIsUnexpected",
+            "thisIsUnexpected",
-        "membership: "));
+            "membership: "));
 
     when(zkStatusHandler.getZkRawResponse("zoo2:2181", "ruok")).thenReturn(Arrays.asList(""));