Rest HL client: Add get license action (#32438)

Rest HL client: Add get license action

Continues to use String instead of a more complex License class to
hold the license text similarly to put license.

Relates #29827

Author: imotov

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

@@ -19,11 +19,25 @@
 
 package org.elasticsearch.client;
 
+import org.apache.http.HttpEntity;
 import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.io.Streams;
+import org.elasticsearch.common.xcontent.DeprecationHandler;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.protocol.xpack.license.GetLicenseRequest;
+import org.elasticsearch.protocol.xpack.license.GetLicenseResponse;
 import org.elasticsearch.protocol.xpack.license.PutLicenseRequest;
 import org.elasticsearch.protocol.xpack.license.PutLicenseResponse;
 
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
 
 import static java.util.Collections.emptySet;
 
@@ -54,7 +68,7 @@ public PutLicenseResponse putLicense(PutLicenseRequest request, RequestOptions o
     }
 
     /**
-     * Asynchronously updates license for the cluster cluster.
+     * Asynchronously updates license for the cluster.
      * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
      * @param listener the listener to be notified upon request completion
      */
@@ -63,4 +77,59 @@ public void putLicenseAsync(PutLicenseRequest request, RequestOptions options, A
             PutLicenseResponse::fromXContent, listener, emptySet());
     }
 
+    /**
+     * Returns the current license for the cluster.
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @return the response
+     * @throws IOException in case there is a problem sending the request or parsing back the response
+     */
+    public GetLicenseResponse getLicense(GetLicenseRequest request, RequestOptions options) throws IOException {
+        return restHighLevelClient.performRequest(request, RequestConverters::getLicense, options,
+            response -> new GetLicenseResponse(convertResponseToJson(response)), emptySet());
+    }
+
+    /**
+     * Asynchronously returns the current license for the cluster cluster.
+     * @param options the request options (e.g. headers), use {@link RequestOptions#DEFAULT} if nothing needs to be customized
+     * @param listener the listener to be notified upon request completion
+     */
+    public void getLicenseAsync(GetLicenseRequest request, RequestOptions options, ActionListener<GetLicenseResponse> listener) {
+        restHighLevelClient.performRequestAsync(request, RequestConverters::getLicense, options,
+            response -> new GetLicenseResponse(convertResponseToJson(response)), listener, emptySet());
+    }
+
+
+    /**
+     * Converts an entire response into a json sting
+     *
+     * This is useful for responses that we don't parse on the client side, but instead work as string
+     * such as in case of the license JSON
+     */
+    static String convertResponseToJson(Response response) throws IOException {
+        HttpEntity entity = response.getEntity();
+        if (entity == null) {
+            throw new IllegalStateException("Response body expected but not returned");
+        }
+        if (entity.getContentType() == null) {
+            throw new IllegalStateException("Elasticsearch didn't return the [Content-Type] header, unable to parse response body");
+        }
+        XContentType xContentType = XContentType.fromMediaTypeOrFormat(entity.getContentType().getValue());
+        if (xContentType == null) {
+            throw new IllegalStateException("Unsupported Content-Type: " + entity.getContentType().getValue());
+        }
+        if (xContentType == XContentType.JSON) {
+            // No changes is required
+            return Streams.copyToString(new InputStreamReader(response.getEntity().getContent(), StandardCharsets.UTF_8));
+        } else {
+            // Need to convert into JSON
+            try (InputStream stream = response.getEntity().getContent();
+                 XContentParser parser = XContentFactory.xContent(xContentType).createParser(NamedXContentRegistry.EMPTY,
+                     DeprecationHandler.THROW_UNSUPPORTED_OPERATION, stream)) {
+                parser.nextToken();
+                XContentBuilder builder = XContentFactory.jsonBuilder();
+                builder.copyCurrentStructure(parser);
+                return Strings.toString(builder);
+            }
+        }
+    }
 }

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

@@ -107,10 +107,11 @@
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.rankeval.RankEvalRequest;
 import org.elasticsearch.protocol.xpack.XPackInfoRequest;
+import org.elasticsearch.protocol.xpack.license.GetLicenseRequest;
+import org.elasticsearch.protocol.xpack.license.PutLicenseRequest;
 import org.elasticsearch.protocol.xpack.watcher.DeleteWatchRequest;
 import org.elasticsearch.protocol.xpack.watcher.PutWatchRequest;
 import org.elasticsearch.protocol.xpack.XPackUsageRequest;
-import org.elasticsearch.protocol.xpack.license.PutLicenseRequest;
 import org.elasticsearch.rest.action.search.RestSearchAction;
 import org.elasticsearch.script.mustache.MultiSearchTemplateRequest;
 import org.elasticsearch.script.mustache.SearchTemplateRequest;
@@ -1154,7 +1155,11 @@ static Request xpackUsage(XPackUsageRequest usageRequest) {
     }
 
     static Request putLicense(PutLicenseRequest putLicenseRequest) {
-        Request request = new Request(HttpPut.METHOD_NAME, "/_xpack/license");
+        String endpoint = new EndpointBuilder()
+            .addPathPartAsIs("_xpack")
+            .addPathPartAsIs("license")
+            .build();
+        Request request = new Request(HttpPut.METHOD_NAME, endpoint);
         Params parameters = new Params(request);
         parameters.withTimeout(putLicenseRequest.timeout());
         parameters.withMasterTimeout(putLicenseRequest.masterNodeTimeout());
@@ -1165,6 +1170,18 @@ static Request putLicense(PutLicenseRequest putLicenseRequest) {
         return request;
     }
 
+
+    static Request getLicense(GetLicenseRequest getLicenseRequest) {
+        String endpoint = new EndpointBuilder()
+            .addPathPartAsIs("_xpack")
+            .addPathPartAsIs("license")
+            .build();
+        Request request = new Request(HttpGet.METHOD_NAME, endpoint);
+        Params parameters = new Params(request);
+        parameters.withLocal(getLicenseRequest.local());
+        return request;
+    }
+
     private static HttpEntity createEntity(ToXContent toXContent, XContentType xContentType) throws IOException {
         BytesRef source = XContentHelper.toXContent(toXContent, xContentType, false).toBytesRef();
         return new ByteArrayEntity(source.bytes, source.offset, source.length, createContentType(xContentType));

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

@@ -25,6 +25,8 @@
 import org.elasticsearch.client.ESRestHighLevelClientTestCase;
 import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.RestHighLevelClient;
+import org.elasticsearch.protocol.xpack.license.GetLicenseRequest;
+import org.elasticsearch.protocol.xpack.license.GetLicenseResponse;
 import org.elasticsearch.protocol.xpack.license.LicensesStatus;
 import org.elasticsearch.protocol.xpack.license.PutLicenseRequest;
 import org.elasticsearch.protocol.xpack.license.PutLicenseResponse;
@@ -33,6 +35,8 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.endsWith;
 import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.startsWith;
@@ -105,4 +109,62 @@ public void onFailure(Exception e) {
             assertTrue(latch.await(30L, TimeUnit.SECONDS));
         }
     }
+
+    public void testGetLicense() throws Exception {
+        RestHighLevelClient client = highLevelClient();
+        {
+            //tag::get-license-execute
+            GetLicenseRequest request = new GetLicenseRequest();
+
+            GetLicenseResponse response = client.license().getLicense(request, RequestOptions.DEFAULT);
+            //end::get-license-execute
+
+            //tag::get-license-response
+            String currentLicense = response.getLicenseDefinition(); // <1>
+            //end::get-license-response
+
+            assertThat(currentLicense, containsString("trial"));
+            assertThat(currentLicense, containsString("client_rest-high-level_integTestCluster"));
+        }
+        {
+            GetLicenseRequest request = new GetLicenseRequest();
+            // tag::get-license-execute-listener
+            ActionListener<GetLicenseResponse> listener = new ActionListener<GetLicenseResponse>() {
+                @Override
+                public void onResponse(GetLicenseResponse indexResponse) {
+                    // <1>
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    // <2>
+                }
+            };
+            // end::get-license-execute-listener
+
+            // Replace the empty listener by a blocking listener in test
+            final CountDownLatch latch = new CountDownLatch(1);
+            listener = new LatchedActionListener<>(listener, latch);
+
+            // tag::get-license-execute-async
+            client.license().getLicenseAsync(
+                request, RequestOptions.DEFAULT, listener); // <1>
+            // end::get-license-execute-async
+
+            assertTrue(latch.await(30L, TimeUnit.SECONDS));
+        }
+        {
+            GetLicenseRequest request = new GetLicenseRequest();
+            RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
+            // Make sure that it still works in other formats
+            builder.addHeader("Accept", randomFrom("application/smile", "application/cbor"));
+            RequestOptions options = builder.build();
+            GetLicenseResponse response = client.license().getLicense(request, options);
+            String currentLicense = response.getLicenseDefinition();
+            assertThat(currentLicense, startsWith("{"));
+            assertThat(currentLicense, containsString("trial"));
+            assertThat(currentLicense, containsString("client_rest-high-level_integTestCluster"));
+            assertThat(currentLicense, endsWith("}"));
+        }
+    }
 }

docs/java-rest/high-level/licensing/get-license.asciidoc

@@ -0,0 +1,50 @@
+[[java-rest-high-get-license]]
+=== Get License
+
+[[java-rest-high-get-license-execution]]
+==== Execution
+
+The license can be added or updated using the `getLicense()` method:
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/LicensingDocumentationIT.java[get-license-execute]
+--------------------------------------------------
+
+[[java-rest-high-get-license-response]]
+==== Response
+
+The returned `GetLicenseResponse` contains the license in the JSON format.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/LicensingDocumentationIT.java[get-license-response]
+--------------------------------------------------
+<1> The text of the license.
+
+[[java-rest-high-get-license-async]]
+==== Asynchronous Execution
+
+This request can be executed asynchronously:
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/LicensingDocumentationIT.java[get-license-execute-async]
+--------------------------------------------------
+<1> The `GetLicenseRequest` to execute and the `ActionListener` to use when
+the execution completes
+
+The asynchronous method does not block and returns immediately. Once it is
+completed the `ActionListener` is called back using the `onResponse` method
+if the execution successfully completed or using the `onFailure` method if
+it failed.
+
+A typical listener for `GetLicenseResponse` looks like:
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/LicensingDocumentationIT.java[get-license-execute-listener]
+--------------------------------------------------
+<1> Called when the execution is successfully completed. The response is
+provided as an argument
+<2> Called in case of failure. The raised exception is provided as an argument

x-pack/plugin/core/src/main/java/org/elasticsearch/license/GetLicenseRequest.java

@@ -7,6 +7,7 @@
 
 import org.elasticsearch.action.support.master.MasterNodeReadOperationRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
+import org.elasticsearch.protocol.xpack.license.GetLicenseRequest;
 
 public class GetLicenseRequestBuilder extends MasterNodeReadOperationRequestBuilder<GetLicenseRequest, GetLicenseResponse,
         GetLicenseRequestBuilder> {

x-pack/plugin/core/src/main/java/org/elasticsearch/license/GetLicenseRequestBuilder.java

@@ -7,6 +7,7 @@
 
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.client.ElasticsearchClient;
+import org.elasticsearch.protocol.xpack.license.GetLicenseRequest;
 import org.elasticsearch.protocol.xpack.license.PutLicenseResponse;
 
 public class LicensingClient {

x-pack/plugin/core/src/main/java/org/elasticsearch/license/LicensingClient.java

@@ -9,6 +9,7 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.protocol.xpack.license.GetLicenseRequest;
 import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;

x-pack/plugin/core/src/main/java/org/elasticsearch/license/RestGetLicenseAction.java

@@ -16,6 +16,7 @@
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.protocol.xpack.license.GetLicenseRequest;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 

x-pack/plugin/core/src/main/java/org/elasticsearch/license/TransportGetLicenseAction.java

@@ -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.
+ */
+package org.elasticsearch.protocol.xpack.license;
+
+import org.elasticsearch.action.ActionRequestValidationException;
+import org.elasticsearch.action.support.master.MasterNodeReadRequest;
+import org.elasticsearch.common.io.stream.StreamInput;
+
+import java.io.IOException;
+
+
+public class GetLicenseRequest extends MasterNodeReadRequest<GetLicenseRequest> {
+
+    public GetLicenseRequest() {
+    }
+
+    public GetLicenseRequest(StreamInput in) throws IOException {
+        super(in);
+    }
+
+    @Override
+    public ActionRequestValidationException validate() {
+        return null;
+    }
+}