Re-read policy phase JSON when using ILM's move-to-step API (#48827)

When using the move-to-step API, we should reread the phase JSON from
the latest version of the ILM policy. This allows a user to move to the
same step while re-reading the policy's latest version. For example,
when changing rollover criteria.

While manually messing around with some other things I discovered that
we only reread the policy when using the retry API, not the move-to-step
API. This commit changes the move-to-step API to always read the latest
version of the policy.

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

@@ -6,6 +6,7 @@
 package org.elasticsearch.xpack.core.ilm;
 
 import org.elasticsearch.client.Client;
+import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.StreamInput;
@@ -56,7 +57,7 @@ public class RolloverAction implements LifecycleAction {
         return PARSER.apply(parser, null);
     }
 
-    public RolloverAction(ByteSizeValue maxSize, TimeValue maxAge, Long maxDocs) {
+    public RolloverAction(@Nullable ByteSizeValue maxSize, @Nullable TimeValue maxAge, @Nullable Long maxDocs) {
         if (maxSize == null && maxAge == null && maxDocs == null) {
             throw new IllegalArgumentException("At least one rollover condition must be set.");
         }

x-pack/plugin/ilm/qa/multi-node/src/test/java/org/elasticsearch/xpack/ilm/TimeSeriesLifecycleActionsIT.java

@@ -808,6 +808,42 @@ public class TimeSeriesLifecycleActionsIT extends ESRestTestCase {
         });
     }
 
+    public void testMoveToStepRereadsPolicy() throws Exception {
+        createNewSingletonPolicy("hot", new RolloverAction(null, TimeValue.timeValueHours(1), null), TimeValue.ZERO);
+
+        createIndexWithSettings("test-1", Settings.builder()
+                .put(IndexMetaData.SETTING_NUMBER_OF_SHARDS, 1)
+                .put(IndexMetaData.SETTING_NUMBER_OF_REPLICAS, 0)
+                .put(LifecycleSettings.LIFECYCLE_NAME, policy)
+                .put(RolloverAction.LIFECYCLE_ROLLOVER_ALIAS, "alias"),
+            true);
+
+        assertBusy(() -> assertThat(getStepKeyForIndex("test-1"), equalTo(new StepKey("hot", "rollover", "check-rollover-ready"))));
+
+        createNewSingletonPolicy("hot", new RolloverAction(null, TimeValue.timeValueSeconds(1), null), TimeValue.ZERO);
+
+        // Move to the same step, which should re-read the policy
+        Request moveToStepRequest = new Request("POST", "_ilm/move/test-1");
+        moveToStepRequest.setJsonEntity("{\n" +
+            "  \"current_step\": { \n" +
+            "    \"phase\": \"hot\",\n" +
+            "    \"action\": \"rollover\",\n" +
+            "    \"name\": \"check-rollover-ready\"\n" +
+            "  },\n" +
+            "  \"next_step\": { \n" +
+            "    \"phase\": \"hot\",\n" +
+            "    \"action\": \"rollover\",\n" +
+            "    \"name\": \"check-rollover-ready\"\n" +
+            "  }\n" +
+            "}");
+        assertOK(client().performRequest(moveToStepRequest));
+
+        // Make sure we actually rolled over
+        assertBusy(() -> {
+            indexExists("test-000002");
+        });
+    }
+
     public void testCanStopILMWithPolicyUsingNonexistentPolicy() throws Exception {
         createIndexWithSettings(index, Settings.builder().put(IndexMetaData.SETTING_NUMBER_OF_SHARDS, 1)
             .put(IndexMetaData.SETTING_NUMBER_OF_REPLICAS, 0)

x-pack/plugin/ilm/src/main/java/org/elasticsearch/xpack/ilm/IndexLifecycleRunner.java

@@ -317,13 +317,11 @@ public class IndexLifecycleRunner {
      * @param nextStepKey    The next step to move the index into
      * @param nowSupplier    The current-time supplier for updating when steps changed
      * @param stepRegistry   The steps registry to check a step-key's existence in the index's current policy
-     * @param forcePhaseDefinitionRefresh When true, step information will be recompiled from the latest version of the
-     *                                    policy. Otherwise, existing phase definition is used.
      * @return The updated cluster state where the index moved to <code>nextStepKey</code>
      */
     static ClusterState moveClusterStateToStep(String indexName, ClusterState currentState, StepKey currentStepKey,
                                                StepKey nextStepKey, LongSupplier nowSupplier,
-                                               PolicyStepsRegistry stepRegistry, boolean forcePhaseDefinitionRefresh) {
+                                               PolicyStepsRegistry stepRegistry) {
         IndexMetaData idxMeta = currentState.getMetaData().index(indexName);
         validateTransition(idxMeta, currentStepKey, nextStepKey, stepRegistry);
 
@@ -333,7 +331,7 @@ public class IndexLifecycleRunner {
             indexName, currentStepKey, nextStepKey, policy);
 
         return IndexLifecycleRunner.moveClusterStateToNextStep(idxMeta.getIndex(), currentState, currentStepKey,
-            nextStepKey, nowSupplier, forcePhaseDefinitionRefresh);
+            nextStepKey, nowSupplier, true);
     }
 
     static void validateTransition(IndexMetaData idxMeta, StepKey currentStepKey, StepKey nextStepKey, PolicyStepsRegistry stepRegistry) {

x-pack/plugin/ilm/src/main/java/org/elasticsearch/xpack/ilm/IndexLifecycleService.java

@@ -88,7 +88,7 @@ public class IndexLifecycleService
 
     public ClusterState moveClusterStateToStep(ClusterState currentState, String indexName, StepKey currentStepKey, StepKey nextStepKey) {
         return IndexLifecycleRunner.moveClusterStateToStep(indexName, currentState, currentStepKey, nextStepKey,
-            nowSupplier, policyRegistry, false);
+            nowSupplier, policyRegistry);
     }
 
     public ClusterState moveClusterStateToPreviouslyFailedStep(ClusterState currentState, String[] indices) {

x-pack/plugin/ilm/src/test/java/org/elasticsearch/xpack/ilm/IndexLifecycleRunnerTests.java

@@ -839,7 +839,7 @@ public class IndexLifecycleRunnerTests extends ESTestCase {
         ClusterState clusterState = buildClusterState(indexName, indexSettingsBuilder, lifecycleState.build(), policyMetadatas);
         Index index = clusterState.metaData().index(indexName).getIndex();
         ClusterState newClusterState = IndexLifecycleRunner.moveClusterStateToStep(indexName, clusterState, currentStepKey,
-            nextStepKey, () -> now, stepRegistry, false);
+            nextStepKey, () -> now, stepRegistry);
         assertClusterStateOnNextStep(clusterState, index, currentStepKey, nextStepKey, newClusterState, now);
     }
 
@@ -861,7 +861,7 @@ public class IndexLifecycleRunnerTests extends ESTestCase {
         ClusterState clusterState = buildClusterState(indexName, indexSettingsBuilder, lifecycleState.build(), Collections.emptyList());
         IllegalArgumentException exception = expectThrows(IllegalArgumentException.class,
             () -> IndexLifecycleRunner.moveClusterStateToStep(indexName, clusterState, currentStepKey,
-                nextStepKey, () -> now, stepRegistry, false));
+                nextStepKey, () -> now, stepRegistry));
         assertThat(exception.getMessage(), equalTo("index [my_index] is not associated with an Index Lifecycle Policy"));
     }
 
@@ -884,7 +884,7 @@ public class IndexLifecycleRunnerTests extends ESTestCase {
         ClusterState clusterState = buildClusterState(indexName, indexSettingsBuilder, lifecycleState.build(), Collections.emptyList());
         IllegalArgumentException exception = expectThrows(IllegalArgumentException.class,
             () -> IndexLifecycleRunner.moveClusterStateToStep(indexName, clusterState, notCurrentStepKey,
-                nextStepKey, () -> now, stepRegistry, false));
+                nextStepKey, () -> now, stepRegistry));
         assertThat(exception.getMessage(), equalTo("index [my_index] is not on current step " +
             "[{\"phase\":\"not_current_phase\",\"action\":\"not_current_action\",\"name\":\"not_current_step\"}]"));
     }
@@ -907,7 +907,7 @@ public class IndexLifecycleRunnerTests extends ESTestCase {
         ClusterState clusterState = buildClusterState(indexName, indexSettingsBuilder, lifecycleState.build(), Collections.emptyList());
         IllegalArgumentException exception = expectThrows(IllegalArgumentException.class,
             () -> IndexLifecycleRunner.moveClusterStateToStep(indexName, clusterState, currentStepKey,
-                nextStepKey, () -> now, stepRegistry, false));
+                nextStepKey, () -> now, stepRegistry));
         assertThat(exception.getMessage(),
             equalTo("step [{\"phase\":\"next_phase\",\"action\":\"next_action\",\"name\":\"next_step\"}] " +
                 "for index [my_index] with policy [my_policy] does not exist"));