HLRC: Add Get Lifecycle Policy API to HLRC

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

@@ -22,6 +22,8 @@
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.support.master.AcknowledgedResponse;
 import org.elasticsearch.client.indexlifecycle.DeleteLifecyclePolicyRequest;
+import org.elasticsearch.client.indexlifecycle.GetLifecyclePolicyRequest;
+import org.elasticsearch.client.indexlifecycle.GetLifecyclePolicyResponse;
 import org.elasticsearch.client.indexlifecycle.LifecycleManagementStatusRequest;
 import org.elasticsearch.client.indexlifecycle.LifecycleManagementStatusResponse;
 import org.elasticsearch.client.indexlifecycle.PutLifecyclePolicyRequest;
@@ -43,6 +45,35 @@ public class IndexLifecycleClient {
         this.restHighLevelClient = restHighLevelClient;
     }
 
+    /**
+     * Retrieve one or more lifecycle policy definition
+     * See <a href="https://fix-me-when-we-have-docs.com">
+     * the docs</a> for more.
+     * @param request the request
+     * @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 GetLifecyclePolicyResponse getLifecyclePolicy(GetLifecyclePolicyRequest request,
+                                                         RequestOptions options) throws IOException {
+        return restHighLevelClient.performRequestAndParseEntity(request, RequestConverters::getLifecyclePolicy, options,
+            GetLifecyclePolicyResponse::fromXContent, emptySet());
+    }
+
+    /**
+     * Asynchronously retrieve one or more lifecycle policy definition
+     * See <a href="https://fix-me-when-we-have-docs.com">
+     * the docs</a> for more.
+     * @param request the request
+     * @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 getLifecyclePolicyAsync(GetLifecyclePolicyRequest request, RequestOptions options,
+                                        ActionListener<GetLifecyclePolicyResponse> listener) {
+        restHighLevelClient.performRequestAsyncAndParseEntity(request, RequestConverters::getLifecyclePolicy, options,
+            GetLifecyclePolicyResponse::fromXContent, listener, emptySet());
+    }
+
     /**
      * Create or modify a lifecycle definition
      * See <a href="https://fix-me-when-we-have-docs.com">

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

@@ -84,6 +84,7 @@
 import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.action.support.WriteRequest;
 import org.elasticsearch.action.update.UpdateRequest;
+import org.elasticsearch.client.indexlifecycle.GetLifecyclePolicyRequest;
 import org.elasticsearch.client.indexlifecycle.LifecycleManagementStatusRequest;
 import org.elasticsearch.client.indexlifecycle.PutLifecyclePolicyRequest;
 import org.elasticsearch.client.indexlifecycle.DeleteLifecyclePolicyRequest;
@@ -1164,6 +1165,18 @@ static Request xpackUsage(XPackUsageRequest usageRequest) {
         return request;
     }
 
+    static Request getLifecyclePolicy(GetLifecyclePolicyRequest getLifecyclePolicyRequest) {
+        String endpoint = new EndpointBuilder()
+            .addPathPartAsIs("_ilm")
+            .addCommaSeparatedPathParts(getLifecyclePolicyRequest.getPolicyNames())
+            .build();
+        Request request = new Request(HttpGet.METHOD_NAME, endpoint);
+        Params params = new Params(request);
+        params.withMasterTimeout(getLifecyclePolicyRequest.masterNodeTimeout());
+        params.withTimeout(getLifecyclePolicyRequest.timeout());
+        return request;
+    }
+
     static Request putLifecyclePolicy(PutLifecyclePolicyRequest putLifecycleRequest) throws IOException {
         String endpoint = new EndpointBuilder()
             .addPathPartAsIs("_ilm")

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

@@ -0,0 +1,61 @@
+/*
+ * 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.indexlifecycle;
+
+import org.elasticsearch.client.TimedRequest;
+import org.elasticsearch.common.Strings;
+
+import java.util.Arrays;
+
+public class GetLifecyclePolicyRequest extends TimedRequest {
+
+    private final String[] policyNames;
+
+    public GetLifecyclePolicyRequest(String... policyNames) {
+        if (policyNames == null) {
+            this.policyNames = Strings.EMPTY_ARRAY;
+        } else {
+            for (String name : policyNames) {
+                if (name == null) {
+                    throw new IllegalArgumentException("cannot include null policy name");
+                }
+            }
+            this.policyNames = policyNames;
+        }
+    }
+
+    public String[] getPolicyNames() {
+        return policyNames;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        GetLifecyclePolicyRequest request = (GetLifecyclePolicyRequest) o;
+        return Arrays.equals(getPolicyNames(), request.getPolicyNames());
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(getPolicyNames());
+    }
+}

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

@@ -0,0 +1,91 @@
+/*
+ * 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.indexlifecycle;
+
+import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
+import org.elasticsearch.common.collect.ImmutableOpenMap;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.ToXContentObject;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentParser;
+
+import java.io.IOException;
+import java.util.Objects;
+
+import static org.elasticsearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
+
+public class GetLifecyclePolicyResponse implements ToXContentObject {
+
+    private final ImmutableOpenMap<String, LifecyclePolicyMetadata> policies;
+
+    public GetLifecyclePolicyResponse(ImmutableOpenMap<String, LifecyclePolicyMetadata> policies) {
+        this.policies = policies;
+    }
+
+    public ImmutableOpenMap<String, LifecyclePolicyMetadata> getPolicies() {
+        return policies;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+        builder.startObject();
+        for (ObjectObjectCursor<String, LifecyclePolicyMetadata> stringLifecyclePolicyObjectObjectCursor : policies) {
+            builder.field(stringLifecyclePolicyObjectObjectCursor.key, stringLifecyclePolicyObjectObjectCursor.value);
+        }
+        builder.endObject();
+        return builder;
+    }
+
+    public static GetLifecyclePolicyResponse fromXContent(XContentParser parser) throws IOException {
+        ImmutableOpenMap.Builder<String, LifecyclePolicyMetadata> policies = ImmutableOpenMap.builder();
+
+        if (parser.currentToken() == null) {
+            parser.nextToken();
+        }
+        ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.currentToken(), parser::getTokenLocation);
+        parser.nextToken();
+
+        while (!parser.isClosed()) {
+            if (parser.currentToken() == XContentParser.Token.START_OBJECT) {
+                String policyName = parser.currentName();
+                LifecyclePolicyMetadata policyDefinion = LifecyclePolicyMetadata.parse(parser, policyName);
+                policies.put(policyName, policyDefinion);
+            } else {
+                parser.nextToken();
+            }
+        }
+
+        return new GetLifecyclePolicyResponse(policies.build());
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        GetLifecyclePolicyResponse that = (GetLifecyclePolicyResponse) o;
+        return Objects.equals(getPolicies(), that.getPolicies());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getPolicies());
+    }
+}

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

@@ -0,0 +1,56 @@
+/*
+ * 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.indexlifecycle;
+
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.plugins.spi.NamedXContentProvider;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class IndexLifecycleNamedXContentProvider implements NamedXContentProvider {
+
+
+    @Override
+    public List<NamedXContentRegistry.Entry> getNamedXContentParsers() {
+        return Arrays.asList(
+            // ILM
+            new NamedXContentRegistry.Entry(LifecycleAction.class,
+                new ParseField(AllocateAction.NAME),
+                AllocateAction::parse),
+            new NamedXContentRegistry.Entry(LifecycleAction.class,
+                new ParseField(DeleteAction.NAME),
+                DeleteAction::parse),
+            new NamedXContentRegistry.Entry(LifecycleAction.class,
+                new ParseField(ForceMergeAction.NAME),
+                ForceMergeAction::parse),
+            new NamedXContentRegistry.Entry(LifecycleAction.class,
+                new ParseField(ReadOnlyAction.NAME),
+                ReadOnlyAction::parse),
+            new NamedXContentRegistry.Entry(LifecycleAction.class,
+                new ParseField(RolloverAction.NAME),
+                RolloverAction::parse),
+            new NamedXContentRegistry.Entry(LifecycleAction.class,
+                new ParseField(ShrinkAction.NAME),
+                ShrinkAction::parse)
+        );
+    }
+}