Add info method to High Level Rest client

This commit adds support for an info() method to the High Level Rest
client that returns the cluster information usually obtained by performing a
`GET hostname:9200` request.

Author: cbuescher

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

@@ -97,6 +97,10 @@ static Request delete(DeleteRequest deleteRequest) {
         return new Request(HttpDelete.METHOD_NAME, endpoint, parameters.getParams(), null);
     }
 
+    static Request info() {
+        return new Request("GET", "/", Collections.emptyMap(), null);
+    }
+
     static Request bulk(BulkRequest bulkRequest) throws IOException {
         Params parameters = Params.builder();
         parameters.withTimeout(bulkRequest.timeout());

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

@@ -35,6 +35,7 @@
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.action.index.IndexResponse;
 import org.elasticsearch.action.main.MainRequest;
+import org.elasticsearch.action.main.MainResponse;
 import org.elasticsearch.action.update.UpdateRequest;
 import org.elasticsearch.action.update.UpdateResponse;
 import org.elasticsearch.common.CheckedFunction;
@@ -113,6 +114,14 @@ public boolean ping(Header... headers) throws IOException {
                 emptySet(), headers);
     }
 
+    /**
+     * Get the cluster info otherwise provided when calling GET `localhost:9200`
+     */
+    public MainResponse info(Header... headers) throws IOException {
+        return performRequestAndParseEntity(new MainRequest(), (request) -> Request.info(), MainResponse::fromXContent, emptySet(),
+                headers);
+    }
+
     /**
      * Retrieves a document by id using the Get API
      *

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

@@ -41,7 +41,7 @@ public void initHighLevelClient() throws IOException {
     }
 
     @AfterClass
-    public static void cleanupClient() throws IOException {
+    public static void cleanupClient() {
         restHighLevelClient = null;
     }
 

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

@@ -19,13 +19,33 @@
 
 package org.elasticsearch.client;
 
+import org.elasticsearch.action.main.MainResponse;
+
 import java.io.IOException;
+import java.util.Map;
 
 public class PingAndInfoIT extends ESRestHighLevelClientTestCase {
 
     public void testPing() throws IOException {
         assertTrue(highLevelClient().ping());
     }
 
-    //TODO add here integ tests for info api: "GET /" once we have parsing code for MainResponse
+    @SuppressWarnings("unchecked")
+    public void testInfo() throws IOException {
+        MainResponse info = highLevelClient().info();
+        // compare with what the low level client outputs
+        Map<String, Object> infoAsMap = entityAsMap(adminClient().performRequest("GET", "/"));
+        assertEquals(infoAsMap.get("cluster_name"), info.getClusterName().value());
+        assertEquals(infoAsMap.get("cluster_uuid"), info.getClusterUuid());
+
+        // only check node name existence, might be a different one from what was hit by low level client in multi-node cluster
+        assertNotNull(info.getNodeName());
+        Map<String, Object> versionMap = (Map<String, Object>) infoAsMap.get("version");
+        assertEquals(versionMap.get("build_hash"), info.getBuild().shortHash());
+        assertEquals(versionMap.get("build_date"), info.getBuild().date());
+        assertEquals(versionMap.get("build_snapshot"), info.getBuild().isSnapshot());
+        assertEquals(versionMap.get("number"), info.getVersion().toString());
+        assertEquals(versionMap.get("lucene_version"), info.getVersion().luceneVersion.toString());
+    }
+
 }

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

@@ -66,6 +66,14 @@ public void testPing() {
         assertEquals("HEAD", request.method);
     }
 
+    public void testInfo() {
+        Request request = Request.info();
+        assertEquals("/", request.endpoint);
+        assertEquals(0, request.params.size());
+        assertNull(request.entity);
+        assertEquals("GET", request.method);
+    }
+
     public void testGet() {
         getAndExistsTest(Request::get, "GET");
     }

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

@@ -20,6 +20,7 @@
 package org.elasticsearch.client;
 
 import com.fasterxml.jackson.core.JsonParseException;
+
 import org.apache.http.Header;
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpHost;
@@ -33,15 +34,20 @@
 import org.apache.http.message.BasicHttpResponse;
 import org.apache.http.message.BasicRequestLine;
 import org.apache.http.message.BasicStatusLine;
+import org.elasticsearch.Build;
 import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.ActionRequest;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.main.MainRequest;
+import org.elasticsearch.action.main.MainResponse;
+import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.common.CheckedFunction;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.cbor.CborXContent;
 import org.elasticsearch.common.xcontent.smile.SmileXContent;
 import org.elasticsearch.rest.RestStatus;
@@ -59,6 +65,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
+import static org.elasticsearch.common.xcontent.XContentHelper.toXContent;
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.mockito.Matchers.anyMapOf;
 import static org.mockito.Matchers.anyObject;
@@ -79,7 +86,7 @@ public class RestHighLevelClientTests extends ESTestCase {
     private RestHighLevelClient restHighLevelClient;
 
     @Before
-    public void initClient() throws IOException {
+    public void initClient() {
         restClient = mock(RestClient.class);
         restHighLevelClient = new RestHighLevelClient(restClient);
     }
@@ -115,6 +122,21 @@ public void testPingSocketTimeout() throws IOException {
                 Matchers.isNull(HttpEntity.class), argThat(new HeadersVarargMatcher(headers)));
     }
 
+    public void testInfo() throws IOException {
+        Header[] headers = RestClientTestUtil.randomHeaders(random(), "Header");
+        Response response = mock(Response.class);
+        MainResponse testInfo = new MainResponse("nodeName", Version.CURRENT, new ClusterName("clusterName"), "clusterUuid",
+                Build.CURRENT, true);
+        when(response.getEntity()).thenReturn(
+                new StringEntity(toXContent(testInfo, XContentType.JSON, false).utf8ToString(), ContentType.APPLICATION_JSON));
+        when(restClient.performRequest(anyString(), anyString(), anyMapOf(String.class, String.class),
+                anyObject(), anyVararg())).thenReturn(response);
+        MainResponse receivedInfo = restHighLevelClient.info(headers);
+        assertEquals(testInfo, receivedInfo);
+        verify(restClient).performRequest(eq("GET"), eq("/"), eq(Collections.emptyMap()),
+                Matchers.isNull(HttpEntity.class), argThat(new HeadersVarargMatcher(headers)));
+    }
+
     public void testRequestValidation() {
         ActionRequestValidationException validationException = new ActionRequestValidationException();
         validationException.addValidationError("validation error");
@@ -388,7 +410,7 @@ public void testPerformRequestOnResponseExceptionWithIgnoresErrorValidBody() thr
         assertEquals("Elasticsearch exception [type=exception, reason=test error message]", elasticsearchException.getMessage());
     }
 
-    public void testWrapResponseListenerOnSuccess() throws IOException {
+    public void testWrapResponseListenerOnSuccess() {
         {
             TrackingActionListener trackingActionListener = new TrackingActionListener();
             ResponseListener responseListener = restHighLevelClient.wrapResponseListener(
@@ -414,7 +436,7 @@ public void testWrapResponseListenerOnSuccess() throws IOException {
         }
     }
 
-    public void testWrapResponseListenerOnException() throws IOException {
+    public void testWrapResponseListenerOnException() {
         TrackingActionListener trackingActionListener = new TrackingActionListener();
         ResponseListener responseListener = restHighLevelClient.wrapResponseListener(
                 response -> response.getStatusLine().getStatusCode(), trackingActionListener, Collections.emptySet());
@@ -543,7 +565,7 @@ public void testWrapResponseListenerOnResponseExceptionWithIgnoresErrorValidBody
         assertEquals("Elasticsearch exception [type=exception, reason=test error message]", elasticsearchException.getMessage());
     }
 
-    public void testNamedXContents() throws IOException {
+    public void testNamedXContents() {
         List<NamedXContentRegistry.Entry> namedXContents = RestHighLevelClient.getNamedXContents();
         assertEquals(0, namedXContents.size());
     }