[ILM] Add unfollow action

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

@@ -53,7 +53,10 @@ public List<NamedXContentRegistry.Entry> getNamedXContentParsers() {
                 ShrinkAction::parse),
             new NamedXContentRegistry.Entry(LifecycleAction.class,
                 new ParseField(FreezeAction.NAME),
-                FreezeAction::parse)
+                FreezeAction::parse),
+            new NamedXContentRegistry.Entry(LifecycleAction.class,
+                new ParseField(UnfollowAction.NAME),
+                UnfollowAction::parse)
         );
     }
 }

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

@@ -57,9 +57,10 @@ public class LifecyclePolicy implements ToXContentObject {
             throw new IllegalArgumentException("ordered " + PHASES_FIELD.getPreferredName() + " are not supported");
         }, PHASES_FIELD);
 
-        ALLOWED_ACTIONS.put("hot", Sets.newHashSet(RolloverAction.NAME));
-        ALLOWED_ACTIONS.put("warm", Sets.newHashSet(AllocateAction.NAME, ForceMergeAction.NAME, ReadOnlyAction.NAME, ShrinkAction.NAME));
-        ALLOWED_ACTIONS.put("cold", Sets.newHashSet(AllocateAction.NAME, FreezeAction.NAME));
+        ALLOWED_ACTIONS.put("hot", Sets.newHashSet(UnfollowAction.NAME, RolloverAction.NAME));
+        ALLOWED_ACTIONS.put("warm", Sets.newHashSet(UnfollowAction.NAME, AllocateAction.NAME, ForceMergeAction.NAME, ReadOnlyAction.NAME,
+            ShrinkAction.NAME));
+        ALLOWED_ACTIONS.put("cold", Sets.newHashSet(UnfollowAction.NAME, AllocateAction.NAME, FreezeAction.NAME));
         ALLOWED_ACTIONS.put("delete", Sets.newHashSet(DeleteAction.NAME));
     }
 

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

@@ -0,0 +1,74 @@
+/*
+ * 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.Strings;
+import org.elasticsearch.common.xcontent.ObjectParser;
+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;
+
+public class UnfollowAction implements LifecycleAction, ToXContentObject {
+    public static final String NAME = "unfollow";
+
+    private static final ObjectParser<UnfollowAction, Void> PARSER = new ObjectParser<>(NAME, UnfollowAction::new);
+
+    public UnfollowAction() {}
+
+    @Override
+    public String getName() {
+        return NAME;
+    }
+
+    public static UnfollowAction parse(XContentParser parser) {
+        return PARSER.apply(parser, null);
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+        builder.startObject();
+        builder.endObject();
+        return builder;
+    }
+
+    @Override
+    public int hashCode() {
+        return 36970;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (obj.getClass() != getClass()) {
+            return false;
+        }
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return Strings.toString(this);
+    }
+}

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

@@ -48,6 +48,7 @@
 import org.elasticsearch.client.indexlifecycle.ShrinkAction;
 import org.elasticsearch.client.indexlifecycle.StartILMRequest;
 import org.elasticsearch.client.indexlifecycle.StopILMRequest;
+import org.elasticsearch.client.indexlifecycle.UnfollowAction;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.hamcrest.Matchers;
@@ -144,19 +145,20 @@ public void testStartStopILM() throws Exception {
 
     public void testExplainLifecycle() throws Exception {
         Map<String, Phase> lifecyclePhases = new HashMap<>();
-        Map<String, LifecycleAction> hotActions = Collections.singletonMap(
-            RolloverAction.NAME,
-            new RolloverAction(null, TimeValue.timeValueHours(50 * 24), null));
+        Map<String, LifecycleAction> hotActions = new HashMap<>();
+        hotActions.put(RolloverAction.NAME, new RolloverAction(null, TimeValue.timeValueHours(50 * 24), null));
         Phase hotPhase = new Phase("hot", randomFrom(TimeValue.ZERO, null), hotActions);
         lifecyclePhases.put("hot", hotPhase);
 
         Map<String, LifecycleAction> warmActions = new HashMap<>();
+        warmActions.put(UnfollowAction.NAME, new UnfollowAction());
         warmActions.put(AllocateAction.NAME, new AllocateAction(null, null, null, Collections.singletonMap("_name", "node-1")));
         warmActions.put(ShrinkAction.NAME, new ShrinkAction(1));
         warmActions.put(ForceMergeAction.NAME, new ForceMergeAction(1000));
         lifecyclePhases.put("warm", new Phase("warm", TimeValue.timeValueSeconds(1000), warmActions));
 
         Map<String, LifecycleAction> coldActions = new HashMap<>();
+        coldActions.put(UnfollowAction.NAME, new UnfollowAction());
         coldActions.put(AllocateAction.NAME, new AllocateAction(0, null, null, null));
         lifecyclePhases.put("cold", new Phase("cold", TimeValue.timeValueSeconds(2000), coldActions));
 

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

@@ -55,6 +55,7 @@
 import org.elasticsearch.client.indexlifecycle.ReadOnlyAction;
 import org.elasticsearch.client.indexlifecycle.RolloverAction;
 import org.elasticsearch.client.indexlifecycle.ShrinkAction;
+import org.elasticsearch.client.indexlifecycle.UnfollowAction;
 import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.common.CheckedFunction;
 import org.elasticsearch.common.bytes.BytesReference;
@@ -644,7 +645,7 @@ public void testDefaultNamedXContents() {
 
     public void testProvidedNamedXContents() {
         List<NamedXContentRegistry.Entry> namedXContents = RestHighLevelClient.getProvidedNamedXContents();
-        assertEquals(18, namedXContents.size());
+        assertEquals(19, namedXContents.size());
         Map<Class<?>, Integer> categories = new HashMap<>();
         List<String> names = new ArrayList<>();
         for (NamedXContentRegistry.Entry namedXContent : namedXContents) {
@@ -668,7 +669,8 @@ public void testProvidedNamedXContents() {
         assertTrue(names.contains(MeanReciprocalRank.NAME));
         assertTrue(names.contains(DiscountedCumulativeGain.NAME));
         assertTrue(names.contains(ExpectedReciprocalRank.NAME));
-        assertEquals(Integer.valueOf(7), categories.get(LifecycleAction.class));
+        assertEquals(Integer.valueOf(8), categories.get(LifecycleAction.class));
+        assertTrue(names.contains(UnfollowAction.NAME));
         assertTrue(names.contains(AllocateAction.NAME));
         assertTrue(names.contains(DeleteAction.NAME));
         assertTrue(names.contains(ForceMergeAction.NAME));

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

@@ -67,7 +67,8 @@ protected NamedXContentRegistry xContentRegistry() {
             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),
-            new NamedXContentRegistry.Entry(LifecycleAction.class, new ParseField(FreezeAction.NAME), FreezeAction::parse)
+            new NamedXContentRegistry.Entry(LifecycleAction.class, new ParseField(FreezeAction.NAME), FreezeAction::parse),
+            new NamedXContentRegistry.Entry(LifecycleAction.class, new ParseField(UnfollowAction.NAME), UnfollowAction::parse)
         ));
         return new NamedXContentRegistry(entries);
     }

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

@@ -63,7 +63,8 @@ protected NamedXContentRegistry xContentRegistry() {
             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),
-            new NamedXContentRegistry.Entry(LifecycleAction.class, new ParseField(FreezeAction.NAME), FreezeAction::parse)
+            new NamedXContentRegistry.Entry(LifecycleAction.class, new ParseField(FreezeAction.NAME), FreezeAction::parse),
+            new NamedXContentRegistry.Entry(LifecycleAction.class, new ParseField(UnfollowAction.NAME), UnfollowAction::parse)
         ));
         return new NamedXContentRegistry(entries);
     }

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

@@ -39,10 +39,10 @@
 import static org.hamcrest.Matchers.equalTo;
 
 public class LifecyclePolicyTests extends AbstractXContentTestCase<LifecyclePolicy> {
-    private static final Set<String> VALID_HOT_ACTIONS = Sets.newHashSet(RolloverAction.NAME);
-    private static final Set<String> VALID_WARM_ACTIONS = Sets.newHashSet(AllocateAction.NAME, ForceMergeAction.NAME,
+    private static final Set<String> VALID_HOT_ACTIONS = Sets.newHashSet(UnfollowAction.NAME, RolloverAction.NAME);
+    private static final Set<String> VALID_WARM_ACTIONS = Sets.newHashSet(UnfollowAction.NAME, AllocateAction.NAME, ForceMergeAction.NAME,
         ReadOnlyAction.NAME, ShrinkAction.NAME);
-    private static final Set<String> VALID_COLD_ACTIONS = Sets.newHashSet(AllocateAction.NAME, FreezeAction.NAME);
+    private static final Set<String> VALID_COLD_ACTIONS = Sets.newHashSet(UnfollowAction.NAME, AllocateAction.NAME, FreezeAction.NAME);
     private static final Set<String> VALID_DELETE_ACTIONS = Sets.newHashSet(DeleteAction.NAME);
 
     private String lifecycleName;
@@ -67,7 +67,8 @@ protected NamedXContentRegistry xContentRegistry() {
             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),
-            new NamedXContentRegistry.Entry(LifecycleAction.class, new ParseField(FreezeAction.NAME), FreezeAction::parse)
+            new NamedXContentRegistry.Entry(LifecycleAction.class, new ParseField(FreezeAction.NAME), FreezeAction::parse),
+            new NamedXContentRegistry.Entry(LifecycleAction.class, new ParseField(UnfollowAction.NAME), UnfollowAction::parse)
         ));
         return new NamedXContentRegistry(entries);
     }
@@ -210,6 +211,8 @@ public static LifecyclePolicy createRandomPolicy(String lifecycleName) {
                     return ShrinkActionTests.randomInstance();
                 case FreezeAction.NAME:
                     return new FreezeAction();
+                case UnfollowAction.NAME:
+                    return new UnfollowAction();
                 default:
                     throw new IllegalArgumentException("invalid action [" + action + "]");
             }};
@@ -241,6 +244,8 @@ private LifecycleAction getTestAction(String actionName) {
                 return ShrinkActionTests.randomInstance();
             case FreezeAction.NAME:
                 return new FreezeAction();
+            case UnfollowAction.NAME:
+                return new UnfollowAction();
             default:
                 throw new IllegalArgumentException("unsupported phase action [" + actionName + "]");
         }

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

@@ -0,0 +1,43 @@
+/*
+ * 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.xcontent.XContentParser;
+import org.elasticsearch.test.AbstractXContentTestCase;
+
+import java.io.IOException;
+
+public class UnfollowActionTests extends AbstractXContentTestCase<UnfollowAction> {
+
+    @Override
+    protected UnfollowAction createTestInstance() {
+        return new UnfollowAction();
+    }
+
+    @Override
+    protected UnfollowAction doParseInstance(XContentParser parser) throws IOException {
+        return UnfollowAction.parse(parser);
+    }
+
+    @Override
+    protected boolean supportsUnknownFields() {
+        return false;
+    }
+}

docs/reference/ilm/policy-definitions.asciidoc

@@ -571,6 +571,43 @@ PUT _ilm/policy/my_policy
 --------------------------------------------------
 // CONSOLE
 
+[[ilm-unfollow-action]]
+==== Unfollow
+
+This action turns a {ref}/ccr-apis.html[ccr] follower index
+into a regular index. This can be desired when moving follower
+indices into the next phase. Also certain actions like shrink
+and rollover can then be performed safely on follower indices.
+
+If the unfollow action encounters a follower index then
+the following operations will be performed on it:
+
+* Pauses indexing following for the follower index.
+* Closes the follower index.
+* Unfollows the follower index.
+* Opens the follower index (which is at this point is a regular index).
+
+The unfollow action does not have any options and
+if it encounters a non follower index, then the
+unfollow action leaves that index untouched and
+lets the next action operate on this index.
+
+[source,js]
+--------------------------------------------------
+PUT _ilm/policy/my_policy
+{
+  "policy": {
+    "phases": {
+      "hot": {
+        "actions": {
+          "unfollow" : {}
+        }
+      }
+    }
+  }
+}
+--------------------------------------------------
+// CONSOLE
 
 === Full Policy
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/XPackClientPlugin.java

@@ -56,6 +56,7 @@
 import org.elasticsearch.xpack.core.indexlifecycle.RolloverAction;
 import org.elasticsearch.xpack.core.indexlifecycle.ShrinkAction;
 import org.elasticsearch.xpack.core.indexlifecycle.TimeseriesLifecycleType;
+import org.elasticsearch.xpack.core.indexlifecycle.UnfollowAction;
 import org.elasticsearch.xpack.core.indexlifecycle.action.DeleteLifecycleAction;
 import org.elasticsearch.xpack.core.indexlifecycle.action.ExplainLifecycleAction;
 import org.elasticsearch.xpack.core.indexlifecycle.action.GetLifecycleAction;
@@ -427,7 +428,8 @@ public List<NamedWriteableRegistry.Entry> getNamedWriteables() {
                 new NamedWriteableRegistry.Entry(LifecycleAction.class, RolloverAction.NAME, RolloverAction::new),
                 new NamedWriteableRegistry.Entry(LifecycleAction.class, ShrinkAction.NAME, ShrinkAction::new),
                 new NamedWriteableRegistry.Entry(LifecycleAction.class, DeleteAction.NAME, DeleteAction::new),
-                new NamedWriteableRegistry.Entry(LifecycleAction.class, FreezeAction.NAME, FreezeAction::new)
+                new NamedWriteableRegistry.Entry(LifecycleAction.class, FreezeAction.NAME, FreezeAction::new),
+                new NamedWriteableRegistry.Entry(LifecycleAction.class, UnfollowAction.NAME, UnfollowAction::new)
         );
     }
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/indexlifecycle/AbstractUnfollowIndexStep.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.core.indexlifecycle;
+
+import org.elasticsearch.client.Client;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.metadata.IndexMetaData;
+
+import java.util.Map;
+
+import static org.elasticsearch.xpack.core.indexlifecycle.UnfollowAction.CCR_METADATA_KEY;
+
+abstract class AbstractUnfollowIndexStep extends AsyncActionStep {
+
+    AbstractUnfollowIndexStep(StepKey key, StepKey nextStepKey, Client client) {
+        super(key, nextStepKey, client);
+    }
+
+    @Override
+    public final void performAction(IndexMetaData indexMetaData, ClusterState currentClusterState, Listener listener) {
+        String followerIndex = indexMetaData.getIndex().getName();
+        Map<String, String> customIndexMetadata = indexMetaData.getCustomData(CCR_METADATA_KEY);
+        if (customIndexMetadata == null) {
+            listener.onResponse(true);
+            return;
+        }
+
+        innerPerformAction(followerIndex, listener);
+    }
+
+    abstract void innerPerformAction(String followerIndex, Listener listener);
+}

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/indexlifecycle/CloseFollowerIndexStep.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.core.indexlifecycle;
+
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.admin.indices.close.CloseIndexRequest;
+import org.elasticsearch.client.Client;
+
+final class CloseFollowerIndexStep extends AbstractUnfollowIndexStep {
+
+    static final String NAME = "close-follower-index";
+
+    CloseFollowerIndexStep(StepKey key, StepKey nextStepKey, Client client) {
+        super(key, nextStepKey, client);
+    }
+
+    @Override
+    void innerPerformAction(String followerIndex, Listener listener) {
+        CloseIndexRequest closeIndexRequest = new CloseIndexRequest(followerIndex);
+        getClient().admin().indices().close(closeIndexRequest, ActionListener.wrap(
+            r -> {
+                assert r.isAcknowledged() : "close index response is not acknowledged";
+                listener.onResponse(true);
+            },
+            listener::onFailure)
+        );
+    }
+}