add REST high level client gradle submodule and first simple method

The RestHighLevelClient class takes as as an argument a low level client instance RestClient. The first method added is ping, which returns true if the call to HEAD / went ok and false if an IOException was thrown. Any other exception gets bubbled up.

There are two kinds of tests, a unit test (RestHighLevelClientTests) that verifies the interaction between high level and low level client, and an integration test (MainActionIT) which relies on an externally started es cluster to send requests to.

buildSrc/src/main/groovy/org/elasticsearch/gradle/test/StandaloneTestBasePlugin.groovy

@@ -26,6 +26,7 @@ import org.elasticsearch.gradle.VersionProperties
 import org.elasticsearch.gradle.precommit.PrecommitTasks
 import org.gradle.api.Plugin
 import org.gradle.api.Project
+import org.gradle.api.Task
 import org.gradle.api.plugins.JavaBasePlugin
 
 /** Configures the build to have a rest integration test.  */
@@ -40,7 +41,7 @@ public class StandaloneTestBasePlugin implements Plugin<Project> {
         BuildPlugin.configureRepositories(project)
 
         // only setup tests to build
-        project.sourceSets.create('test')
+        project.sourceSets.maybeCreate('test')
         project.dependencies.add('testCompile', "org.elasticsearch.test:framework:${VersionProperties.elasticsearch}")
 
         project.eclipse.classpath.sourceSets = [project.sourceSets.test]
@@ -48,7 +49,10 @@ public class StandaloneTestBasePlugin implements Plugin<Project> {
         project.idea.module.testSourceDirs += project.sourceSets.test.java.srcDirs
         project.idea.module.scopes['TEST'] = [plus: [project.configurations.testRuntime]]
 
+        Task precommitTask = project.tasks.findByName('precommit')
+        if (precommitTask == null) {
             PrecommitTasks.create(project, false)
             project.check.dependsOn(project.precommit)
         }
+    }
 }

client/rest-high-level/build.gradle

@@ -0,0 +1,41 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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.
+ */
+apply plugin: 'elasticsearch.build'
+apply plugin: 'elasticsearch.rest-test'
+
+group = 'org.elasticsearch.client'
+
+dependencies {
+  compile "org.elasticsearch:elasticsearch:${version}"
+  compile "org.elasticsearch.client:rest:${version}"
+
+  testCompile "org.elasticsearch.client:test:${version}"
+  testCompile "org.elasticsearch.test:framework:${version}"
+  testCompile "com.carrotsearch.randomizedtesting:randomizedtesting-runner:${versions.randomizedrunner}"
+  testCompile "junit:junit:${versions.junit}"
+  testCompile "org.hamcrest:hamcrest-all:${versions.hamcrest}"
+}
+
+dependencyLicenses {
+  // Don't check licenses for dependency that are part of the elasticsearch project
+  // But any other dependency should have its license/notice/sha1
+  dependencies = project.configurations.runtime.fileCollection {
+    it.group.startsWith('org.elasticsearch') == false
+  }
+}

client/rest-high-level/src/main/java/org/elasticsearch/client/RestHighLevelClient.java

@@ -0,0 +1,51 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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.elasticsearch.client;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.http.Header;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * High level REST client that wraps an instance of the low level {@link RestClient} and allows to build requests and read responses.
+ * The provided {@link RestClient} is externally built and closed.
+ */
+public final class RestHighLevelClient {
+
+    private static final Log logger = LogFactory.getLog(RestHighLevelClient.class);
+
+    private final RestClient client;
+
+    public RestHighLevelClient(RestClient client) {
+        this.client = Objects.requireNonNull(client);
+    }
+
+    public boolean ping(Header... headers) {
+        try {
+            client.performRequest("HEAD", "/", headers);
+            return true;
+        } catch(IOException exception) {
+            return false;
+        }
+    }
+}

client/rest-high-level/src/test/java/org/elasticsearch/client/ESRestHighLevelClientTestCase.java

@@ -0,0 +1,48 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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.elasticsearch.client;
+
+import org.elasticsearch.test.rest.ESRestTestCase;
+import org.junit.AfterClass;
+import org.junit.Before;
+
+import java.io.IOException;
+
+public abstract class ESRestHighLevelClientTestCase extends ESRestTestCase {
+
+    private static RestHighLevelClient restHighLevelClient;
+
+    @Before
+    public void initHighLevelClient() throws IOException {
+        super.initClient();
+        if (restHighLevelClient == null) {
+            restHighLevelClient = new RestHighLevelClient(client());
+        }
+    }
+
+    @AfterClass
+    public static void cleanupClient() throws IOException {
+        restHighLevelClient = null;
+    }
+
+    protected static RestHighLevelClient highLevelClient() {
+        return restHighLevelClient;
+    }
+}

client/rest-high-level/src/test/java/org/elasticsearch/client/MainActionIT.java

@@ -0,0 +1,27 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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.elasticsearch.client;
+
+public class MainActionIT extends ESRestHighLevelClientTestCase {
+
+    public void testPing() {
+        assertTrue(highLevelClient().ping());
+    }
+}

client/rest-high-level/src/test/java/org/elasticsearch/client/RestHighLevelClientTests.java

@@ -0,0 +1,87 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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.elasticsearch.client;
+
+import org.apache.http.Header;
+import org.elasticsearch.test.ESTestCase;
+import org.junit.Before;
+import org.mockito.ArgumentMatcher;
+import org.mockito.internal.matchers.ArrayEquals;
+import org.mockito.internal.matchers.VarargMatcher;
+
+import java.io.IOException;
+import java.net.SocketTimeoutException;
+
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.argThat;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class RestHighLevelClientTests extends ESTestCase {
+
+    private RestClient restClient;
+    private RestHighLevelClient restHighLevelClient;
+
+    @Before
+    public void initClient() throws IOException {
+        restClient = mock(RestClient.class);
+        restHighLevelClient = new RestHighLevelClient(restClient);
+    }
+
+    public void testPing() throws IOException {
+        assertTrue(restHighLevelClient.ping());
+        verify(restClient).performRequest(eq("HEAD"), eq("/"), argThat(new HeadersVarargMatcher()));
+    }
+
+    public void testPingFailure() throws IOException {
+        when(restClient.performRequest(any(), any())).thenThrow(new IllegalStateException());
+        expectThrows(IllegalStateException.class, () -> restHighLevelClient.ping());
+    }
+
+    public void testPingFailed() throws IOException {
+        when(restClient.performRequest(any(), any())).thenThrow(new SocketTimeoutException());
+        assertFalse(restHighLevelClient.ping());
+    }
+
+    public void testPingWithHeaders() throws IOException {
+        Header[] headers = RestClientTestUtil.randomHeaders(random(), "Header");
+        assertTrue(restHighLevelClient.ping(headers));
+        verify(restClient).performRequest(eq("HEAD"), eq("/"), argThat(new HeadersVarargMatcher(headers)));
+    }
+
+    private class HeadersVarargMatcher extends ArgumentMatcher<Header[]> implements VarargMatcher {
+        private Header[] expectedHeaders;
+
+        HeadersVarargMatcher(Header... expectedHeaders) {
+            this.expectedHeaders = expectedHeaders;
+        }
+
+        @Override
+        public boolean matches(Object varargArgument) {
+            if (varargArgument instanceof Header[]) {
+                Header[] actualHeaders = (Header[]) varargArgument;
+                return new ArrayEquals(expectedHeaders).matches(actualHeaders);
+            }
+            return false;
+        }
+    }
+}

settings.gradle

@@ -7,6 +7,7 @@ List projects = [
   'core',
   'docs',
   'client:rest',
+  'client:rest-high-level',
   'client:sniffer',
   'client:transport',
   'client:test',