Add SLM metrics gathering and endpoint

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

@@ -196,6 +196,7 @@
 import org.elasticsearch.xpack.core.slm.action.DeleteSnapshotLifecycleAction;
 import org.elasticsearch.xpack.core.slm.action.ExecuteSnapshotLifecycleAction;
 import org.elasticsearch.xpack.core.slm.action.GetSnapshotLifecycleAction;
+import org.elasticsearch.xpack.core.slm.action.GetSnapshotLifecycleStatsAction;
 import org.elasticsearch.xpack.core.slm.action.PutSnapshotLifecycleAction;
 import org.elasticsearch.xpack.core.spatial.SpatialFeatureSetUsage;
 import org.elasticsearch.xpack.core.sql.SqlFeatureSetUsage;
@@ -378,6 +379,7 @@ public List<ActionType<? extends ActionResponse>> getClientActions() {
                 GetSnapshotLifecycleAction.INSTANCE,
                 DeleteSnapshotLifecycleAction.INSTANCE,
                 ExecuteSnapshotLifecycleAction.INSTANCE,
+                GetSnapshotLifecycleStatsAction.INSTANCE,
                 // Freeze
                 FreezeIndexAction.INSTANCE,
                 // Data Frame

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

@@ -19,6 +19,7 @@
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.xpack.core.ilm.OperationMode;
+import org.elasticsearch.xpack.slm.SnapshotLifecycleStats;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -38,36 +39,48 @@
 public class SnapshotLifecycleMetadata implements MetaData.Custom {
 
     public static final String TYPE = "snapshot_lifecycle";
-    public static final ParseField OPERATION_MODE_FIELD = new ParseField("operation_mode");
-    public static final ParseField POLICIES_FIELD = new ParseField("policies");
 
-    public static final SnapshotLifecycleMetadata EMPTY = new SnapshotLifecycleMetadata(Collections.emptyMap(), OperationMode.RUNNING);
+    private static final ParseField OPERATION_MODE_FIELD = new ParseField("operation_mode");
+    private static final ParseField POLICIES_FIELD = new ParseField("policies");
+    private static final ParseField STATS_FIELD = new ParseField("stats");
+
+    public static final SnapshotLifecycleMetadata EMPTY =
+        new SnapshotLifecycleMetadata(Collections.emptyMap(), OperationMode.RUNNING, new SnapshotLifecycleStats());
 
     @SuppressWarnings("unchecked")
     public static final ConstructingObjectParser<SnapshotLifecycleMetadata, Void> PARSER = new ConstructingObjectParser<>(TYPE,
         a -> new SnapshotLifecycleMetadata(
             ((List<SnapshotLifecyclePolicyMetadata>) a[0]).stream()
                 .collect(Collectors.toMap(m -> m.getPolicy().getId(), Function.identity())),
-            OperationMode.valueOf((String) a[1])));
+            OperationMode.valueOf((String) a[1]),
+            (SnapshotLifecycleStats) a[2]));
 
     static {
         PARSER.declareNamedObjects(ConstructingObjectParser.constructorArg(), (p, c, n) -> SnapshotLifecyclePolicyMetadata.parse(p, n),
             v -> {
                 throw new IllegalArgumentException("ordered " + POLICIES_FIELD.getPreferredName() + " are not supported");
             }, POLICIES_FIELD);
+        PARSER.declareString(ConstructingObjectParser.constructorArg(), OPERATION_MODE_FIELD);
+        PARSER.declareObject(ConstructingObjectParser.constructorArg(), (v, o) -> SnapshotLifecycleStats.parse(v), STATS_FIELD);
     }
 
     private final Map<String, SnapshotLifecyclePolicyMetadata> snapshotConfigurations;
     private final OperationMode operationMode;
+    private final SnapshotLifecycleStats slmStats;
 
-    public SnapshotLifecycleMetadata(Map<String, SnapshotLifecyclePolicyMetadata> snapshotConfigurations, OperationMode operationMode) {
+    public SnapshotLifecycleMetadata(Map<String, SnapshotLifecyclePolicyMetadata> snapshotConfigurations,
+                                     OperationMode operationMode,
+                                     SnapshotLifecycleStats slmStats) {
         this.snapshotConfigurations = new HashMap<>(snapshotConfigurations);
         this.operationMode = operationMode;
+        this.slmStats = slmStats;
     }
 
     public SnapshotLifecycleMetadata(StreamInput in) throws IOException {
         this.snapshotConfigurations = in.readMap(StreamInput::readString, SnapshotLifecyclePolicyMetadata::new);
         this.operationMode = in.readEnum(OperationMode.class);
+        // TODO: version qualify
+        this.slmStats = new SnapshotLifecycleStats(in);
     }
 
     public Map<String, SnapshotLifecyclePolicyMetadata> getSnapshotConfigurations() {
@@ -78,6 +91,10 @@ public OperationMode getOperationMode() {
         return operationMode;
     }
 
+    public SnapshotLifecycleStats getStats() {
+        return this.slmStats;
+    }
+
     @Override
     public EnumSet<MetaData.XContentContext> context() {
         return MetaData.ALL_CONTEXTS;
@@ -102,12 +119,15 @@ public Version getMinimalSupportedVersion() {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeMap(this.snapshotConfigurations, StreamOutput::writeString, (out1, value) -> value.writeTo(out1));
         out.writeEnum(this.operationMode);
+        // TODO: version qualify
+        this.slmStats.writeTo(out);
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.field(POLICIES_FIELD.getPreferredName(), this.snapshotConfigurations);
         builder.field(OPERATION_MODE_FIELD.getPreferredName(), operationMode);
+        builder.field(STATS_FIELD.getPreferredName(), this.slmStats);
         return builder;
     }
 
@@ -118,7 +138,7 @@ public String toString() {
 
     @Override
     public int hashCode() {
-        return Objects.hash(this.snapshotConfigurations, this.operationMode);
+        return Objects.hash(this.snapshotConfigurations, this.operationMode, this.slmStats);
     }
 
     @Override
@@ -131,32 +151,37 @@ public boolean equals(Object obj) {
         }
         SnapshotLifecycleMetadata other = (SnapshotLifecycleMetadata) obj;
         return this.snapshotConfigurations.equals(other.snapshotConfigurations) &&
-            this.operationMode.equals(other.operationMode);
+            this.operationMode.equals(other.operationMode) &&
+            this.slmStats.equals(other.slmStats);
     }
 
     public static class SnapshotLifecycleMetadataDiff implements NamedDiff<MetaData.Custom> {
 
         final Diff<Map<String, SnapshotLifecyclePolicyMetadata>> lifecycles;
         final OperationMode operationMode;
+        final SnapshotLifecycleStats slmStats;
 
         SnapshotLifecycleMetadataDiff(SnapshotLifecycleMetadata before, SnapshotLifecycleMetadata after) {
             this.lifecycles = DiffableUtils.diff(before.snapshotConfigurations, after.snapshotConfigurations,
                 DiffableUtils.getStringKeySerializer());
             this.operationMode = after.operationMode;
+            this.slmStats = after.slmStats;
         }
 
         public SnapshotLifecycleMetadataDiff(StreamInput in) throws IOException {
             this.lifecycles = DiffableUtils.readJdkMapDiff(in, DiffableUtils.getStringKeySerializer(),
                 SnapshotLifecyclePolicyMetadata::new,
                 SnapshotLifecycleMetadataDiff::readLifecyclePolicyDiffFrom);
             this.operationMode = in.readEnum(OperationMode.class);
+            // TODO: version qualify this
+            this.slmStats = new SnapshotLifecycleStats(in);
         }
 
         @Override
         public MetaData.Custom apply(MetaData.Custom part) {
             TreeMap<String, SnapshotLifecyclePolicyMetadata> newLifecycles = new TreeMap<>(
                 lifecycles.apply(((SnapshotLifecycleMetadata) part).snapshotConfigurations));
-            return new SnapshotLifecycleMetadata(newLifecycles, this.operationMode);
+            return new SnapshotLifecycleMetadata(newLifecycles, this.operationMode, this.slmStats);
         }
 
         @Override
@@ -168,6 +193,8 @@ public String getWriteableName() {
         public void writeTo(StreamOutput out) throws IOException {
             lifecycles.writeTo(out);
             out.writeEnum(this.operationMode);
+            // TODO: version qualify this
+            this.slmStats.writeTo(out);
         }
 
         static Diff<SnapshotLifecyclePolicyMetadata> readLifecyclePolicyDiffFrom(StreamInput in) throws IOException {

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/slm/action/GetSnapshotLifecycleStatsAction.java

@@ -0,0 +1,102 @@
+/*
+ * 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.slm.action;
+
+import org.elasticsearch.action.ActionRequestValidationException;
+import org.elasticsearch.action.ActionResponse;
+import org.elasticsearch.action.ActionType;
+import org.elasticsearch.action.support.master.AcknowledgedRequest;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.ToXContentObject;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.xpack.slm.SnapshotLifecycleStats;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * This class represents the action of retriving the stats for snapshot lifecycle management.
+ * These are retrieved from the master's cluster state and contain numbers related to the count of
+ * snapshots taken or deleted, as well as retention runs and time spent deleting snapshots.
+ */
+public class GetSnapshotLifecycleStatsAction extends ActionType<GetSnapshotLifecycleStatsAction.Response> {
+    public static final GetSnapshotLifecycleStatsAction INSTANCE = new GetSnapshotLifecycleStatsAction();
+    public static final String NAME = "cluster:admin/slm/stats";
+
+    protected GetSnapshotLifecycleStatsAction() {
+        super(NAME, GetSnapshotLifecycleStatsAction.Response::new);
+    }
+
+    public static class Request extends AcknowledgedRequest<GetSnapshotLifecycleStatsAction.Request> {
+
+        public Request() { }
+
+        public Request(StreamInput in) throws IOException {
+            super(in);
+        }
+
+        @Override
+        public ActionRequestValidationException validate() {
+            return null;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            super.writeTo(out);
+        }
+    }
+
+    public static class Response extends ActionResponse implements ToXContentObject {
+
+        private SnapshotLifecycleStats slmStats;
+
+        public Response() { }
+
+        public Response(SnapshotLifecycleStats slmStats) {
+            this.slmStats = slmStats;
+        }
+
+        public Response(StreamInput in) throws IOException {
+            this.slmStats = new SnapshotLifecycleStats(in);
+        }
+
+        @Override
+        public String toString() {
+            return Strings.toString(this);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            return this.slmStats.toXContent(builder, params);
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            this.slmStats.writeTo(out);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(this.slmStats);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null) {
+                return false;
+            }
+            if (obj.getClass() != getClass()) {
+                return false;
+            }
+            GetSnapshotLifecycleStatsAction.Response other = (GetSnapshotLifecycleStatsAction.Response) obj;
+            return this.slmStats.equals(other.slmStats);
+        }
+    }
+
+}