Add SLM support to xpack usage and info APIs (#48149)

* Add SLM support to xpack usage and info APIs

This is a backport of #48096

This adds the missing xpack usage and info information into the
`/_xpack` and `/_xpack/usage` APIs. The output now looks like:

```
GET /_xpack/usage
{
  ...
  "slm" : {
    "available" : true,
    "enabled" : true,
    "policy_count" : 1,
    "policy_stats" : {
      "retention_runs" : 0,
      ...
    }
  }
```

and

```
GET /_xpack
{
  ...
  "features" : {
    ...
    "slm" : {
      "available" : true,
      "enabled" : true
    },
    ...
  }
}
```

Relates to #43663

* Fix missing license

docs/reference/rest-api/info.asciidoc

@@ -111,6 +111,10 @@ Example response:
          "available" : true,
          "enabled" : false
       },
+      "slm" : {
+         "available" : true,
+         "enabled" : true
+      },
       "spatial" : {
          "available" : true,
          "enabled" : true

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

@@ -38,10 +38,10 @@ import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.Transport;
 import org.elasticsearch.xpack.core.action.XPackInfoAction;
 import org.elasticsearch.xpack.core.action.XPackUsageAction;
+import org.elasticsearch.xpack.core.analytics.AnalyticsFeatureSetUsage;
 import org.elasticsearch.xpack.core.beats.BeatsFeatureSetUsage;
 import org.elasticsearch.xpack.core.ccr.AutoFollowMetadata;
 import org.elasticsearch.xpack.core.ccr.CCRFeatureSet;
-import org.elasticsearch.xpack.core.analytics.AnalyticsFeatureSetUsage;
 import org.elasticsearch.xpack.core.deprecation.DeprecationInfoAction;
 import org.elasticsearch.xpack.core.enrich.action.DeleteEnrichPolicyAction;
 import org.elasticsearch.xpack.core.enrich.action.ExecuteEnrichPolicyAction;
@@ -152,12 +152,12 @@ import org.elasticsearch.xpack.core.ml.dataframe.evaluation.softclassification.P
 import org.elasticsearch.xpack.core.ml.dataframe.evaluation.softclassification.Recall;
 import org.elasticsearch.xpack.core.ml.dataframe.evaluation.softclassification.ScoreByThresholdResult;
 import org.elasticsearch.xpack.core.ml.dataframe.evaluation.softclassification.SoftClassificationMetric;
-import org.elasticsearch.xpack.core.ml.inference.trainedmodel.TrainedModel;
-import org.elasticsearch.xpack.core.ml.inference.trainedmodel.tree.Tree;
 import org.elasticsearch.xpack.core.ml.inference.preprocessing.FrequencyEncoding;
 import org.elasticsearch.xpack.core.ml.inference.preprocessing.OneHotEncoding;
 import org.elasticsearch.xpack.core.ml.inference.preprocessing.PreProcessor;
 import org.elasticsearch.xpack.core.ml.inference.preprocessing.TargetMeanEncoding;
+import org.elasticsearch.xpack.core.ml.inference.trainedmodel.TrainedModel;
+import org.elasticsearch.xpack.core.ml.inference.trainedmodel.tree.Tree;
 import org.elasticsearch.xpack.core.ml.job.config.JobTaskState;
 import org.elasticsearch.xpack.core.monitoring.MonitoringFeatureSetUsage;
 import org.elasticsearch.xpack.core.rollup.RollupFeatureSetUsage;
@@ -204,6 +204,7 @@ import org.elasticsearch.xpack.core.security.authc.support.mapper.expressiondsl.
 import org.elasticsearch.xpack.core.security.authz.privilege.ConfigurableClusterPrivilege;
 import org.elasticsearch.xpack.core.security.authz.privilege.ConfigurableClusterPrivileges;
 import org.elasticsearch.xpack.core.security.transport.netty4.SecurityNetty4Transport;
+import org.elasticsearch.xpack.core.slm.SLMFeatureSetUsage;
 import org.elasticsearch.xpack.core.slm.SnapshotLifecycleMetadata;
 import org.elasticsearch.xpack.core.slm.action.DeleteSnapshotLifecycleAction;
 import org.elasticsearch.xpack.core.slm.action.ExecuteSnapshotLifecycleAction;
@@ -223,10 +224,10 @@ import org.elasticsearch.xpack.core.transform.action.PreviewTransformAction;
 import org.elasticsearch.xpack.core.transform.action.PutTransformAction;
 import org.elasticsearch.xpack.core.transform.action.StartTransformAction;
 import org.elasticsearch.xpack.core.transform.action.StopTransformAction;
-import org.elasticsearch.xpack.core.transform.transforms.TransformTaskParams;
-import org.elasticsearch.xpack.core.transform.transforms.TransformState;
 import org.elasticsearch.xpack.core.transform.transforms.SyncConfig;
 import org.elasticsearch.xpack.core.transform.transforms.TimeSyncConfig;
+import org.elasticsearch.xpack.core.transform.transforms.TransformState;
+import org.elasticsearch.xpack.core.transform.transforms.TransformTaskParams;
 import org.elasticsearch.xpack.core.upgrade.actions.IndexUpgradeAction;
 import org.elasticsearch.xpack.core.upgrade.actions.IndexUpgradeInfoAction;
 import org.elasticsearch.xpack.core.vectors.VectorsFeatureSetUsage;
@@ -544,6 +545,9 @@ public class XPackClientPlugin extends Plugin implements ActionPlugin, NetworkPl
                 // ILM
                 new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.INDEX_LIFECYCLE,
                     IndexLifecycleFeatureSetUsage::new),
+                // SLM
+                new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.SNAPSHOT_LIFECYCLE,
+                    SLMFeatureSetUsage::new),
                 // ILM - Custom Metadata
                 new NamedWriteableRegistry.Entry(MetaData.Custom.class, IndexLifecycleMetadata.TYPE, IndexLifecycleMetadata::new),
                 new NamedWriteableRegistry.Entry(NamedDiff.class, IndexLifecycleMetadata.TYPE,

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

@@ -33,6 +33,8 @@ public final class XPackField {
     public static final String ROLLUP = "rollup";
     /** Name constant for the index lifecycle feature. */
     public static final String INDEX_LIFECYCLE = "ilm";
+    /** Name constant for the snapshot lifecycle management feature. */
+    public static final String SNAPSHOT_LIFECYCLE = "slm";
     /** Name constant for the CCR feature. */
     public static final String CCR = "ccr";
     /** Name constant for the transform feature. */

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

@@ -0,0 +1,72 @@
+/*
+ * 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;
+
+import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.xpack.core.XPackFeatureSet;
+import org.elasticsearch.xpack.core.XPackField;
+import org.elasticsearch.xpack.slm.SnapshotLifecycleStats;
+
+import java.io.IOException;
+import java.util.Objects;
+
+public class SLMFeatureSetUsage extends XPackFeatureSet.Usage {
+    @Nullable
+    private final SnapshotLifecycleStats slmStats;
+
+    public SLMFeatureSetUsage(StreamInput in) throws IOException {
+        super(in);
+        this.slmStats = in.readOptionalWriteable(SnapshotLifecycleStats::new);
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeOptionalWriteable(this.slmStats);
+    }
+
+    public SLMFeatureSetUsage(boolean available, boolean enabled, @Nullable SnapshotLifecycleStats slmStats) {
+        super(XPackField.SNAPSHOT_LIFECYCLE, available, enabled);
+        this.slmStats = slmStats;
+    }
+
+    public SnapshotLifecycleStats getStats() {
+        return this.slmStats;
+    }
+
+    @Override
+    protected void innerXContent(XContentBuilder builder, Params params) throws IOException {
+        super.innerXContent(builder, params);
+        if (slmStats != null) {
+            builder.field("policy_count", slmStats.getMetrics().size());
+            builder.field("policy_stats", slmStats);
+        }
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(available, enabled, slmStats);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        SLMFeatureSetUsage other = (SLMFeatureSetUsage) obj;
+        return Objects.equals(available, other.available) &&
+            Objects.equals(enabled, other.enabled) &&
+            Objects.equals(slmStats, other.slmStats);
+    }
+
+}

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

@@ -49,6 +49,7 @@ import static org.elasticsearch.xpack.core.slm.history.SnapshotHistoryItem.CREAT
 import static org.elasticsearch.xpack.core.slm.history.SnapshotHistoryItem.DELETE_OPERATION;
 import static org.elasticsearch.xpack.core.slm.history.SnapshotHistoryStore.SLM_HISTORY_INDEX_PREFIX;
 import static org.elasticsearch.xpack.ilm.TimeSeriesLifecycleActionsIT.getStepKeyForIndex;
+import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
@@ -422,6 +423,76 @@ public class SnapshotLifecycleRestIT extends ESRestTestCase {
         }
     }
 
+    @SuppressWarnings("unchecked")
+    public void testSLMXpackInfo() {
+        Map<String, Object> features = (Map<String, Object>) getLocation("/_xpack").get("features");
+        assertNotNull(features);
+        Map<String, Object> slm = (Map<String, Object>) features.get("slm");
+        assertNotNull(slm);
+        assertTrue((boolean) slm.get("available"));
+        assertTrue((boolean) slm.get("enabled"));
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testSLMXpackUsage() throws Exception {
+        Map<String, Object> slm = (Map<String, Object>) getLocation("/_xpack/usage").get("slm");
+        assertNotNull(slm);
+        assertTrue((boolean) slm.get("available"));
+        assertTrue((boolean) slm.get("enabled"));
+        assertThat(slm.get("policy_count"), anyOf(equalTo(null), equalTo(0)));
+
+        // Create a snapshot repo
+        initializeRepo("repo");
+        // Create a policy with a retention period of 1 millisecond
+        createSnapshotPolicy("policy", "snap", "1 2 3 4 5 ?", "repo", "*", true,
+            new SnapshotRetentionConfiguration(TimeValue.timeValueMillis(1), null, null));
+        final String snapshotName = executePolicy("policy");
+
+        // Check that the executed snapshot is created
+        assertBusy(() -> {
+            try {
+                logger.info("--> checking for snapshot creation...");
+                Response response = client().performRequest(new Request("GET", "/_snapshot/repo/" + snapshotName));
+                Map<String, Object> snapshotResponseMap;
+                try (InputStream is = response.getEntity().getContent()) {
+                    snapshotResponseMap = XContentHelper.convertToMap(XContentType.JSON.xContent(), is, true);
+                }
+                assertThat(snapshotResponseMap.size(), greaterThan(0));
+            } catch (ResponseException e) {
+                fail("expected snapshot to exist but it does not: " + EntityUtils.toString(e.getResponse().getEntity()));
+            }
+        });
+
+        // Wait for stats to be updated
+        assertBusy(() -> {
+            logger.info("--> checking for stats to be updated...");
+            Map<String, Object> stats = getSLMStats();
+            Map<String, Object> policyStats = policyStatsAsMap(stats);
+            Map<String, Object> policyIdStats = (Map<String, Object>) policyStats.get("policy");
+            assertNotNull(policyIdStats);
+        });
+
+        slm = (Map<String, Object>) getLocation("/_xpack/usage").get("slm");
+        assertNotNull(slm);
+        assertTrue((boolean) slm.get("available"));
+        assertTrue((boolean) slm.get("enabled"));
+        assertThat("got: " + slm, slm.get("policy_count"), equalTo(1));
+        assertNotNull(slm.get("policy_stats"));
+    }
+
+    public Map<String, Object> getLocation(String path) {
+        try {
+            Response executeRepsonse = client().performRequest(new Request("GET", path));
+            try (XContentParser parser = JsonXContent.jsonXContent.createParser(NamedXContentRegistry.EMPTY,
+                DeprecationHandler.THROW_UNSUPPORTED_OPERATION, EntityUtils.toByteArray(executeRepsonse.getEntity()))) {
+                return parser.map();
+            }
+        } catch (Exception e) {
+            fail("failed to execute GET request to " + path + " - got: " + e);
+            throw new RuntimeException(e);
+        }
+    }
+
     /**
      * Execute the given policy and return the generated snapshot name
      */

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

@@ -94,6 +94,7 @@ import org.elasticsearch.xpack.ilm.action.TransportRemoveIndexLifecyclePolicyAct
 import org.elasticsearch.xpack.ilm.action.TransportRetryAction;
 import org.elasticsearch.xpack.ilm.action.TransportStartILMAction;
 import org.elasticsearch.xpack.ilm.action.TransportStopILMAction;
+import org.elasticsearch.xpack.slm.SLMFeatureSet;
 import org.elasticsearch.xpack.slm.SnapshotLifecycleService;
 import org.elasticsearch.xpack.slm.SnapshotLifecycleTask;
 import org.elasticsearch.xpack.slm.SnapshotRetentionService;
@@ -158,6 +159,7 @@ public class IndexLifecycle extends Plugin implements ActionPlugin {
         }
 
         modules.add(b -> XPackPlugin.bindFeatureSet(b, IndexLifecycleFeatureSet.class));
+        modules.add(b -> XPackPlugin.bindFeatureSet(b, SLMFeatureSet.class));
 
         return modules;
     }

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

@@ -0,0 +1,67 @@
+/*
+ * 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.slm;
+
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.service.ClusterService;
+import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.inject.Inject;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.license.XPackLicenseState;
+import org.elasticsearch.xpack.core.XPackFeatureSet;
+import org.elasticsearch.xpack.core.XPackField;
+import org.elasticsearch.xpack.core.XPackSettings;
+import org.elasticsearch.xpack.core.slm.SLMFeatureSetUsage;
+import org.elasticsearch.xpack.core.slm.SnapshotLifecycleMetadata;
+
+import java.util.Map;
+
+public class SLMFeatureSet implements XPackFeatureSet {
+
+    private final boolean enabled;
+    private final XPackLicenseState licenseState;
+    private ClusterService clusterService;
+
+    @Inject
+    public SLMFeatureSet(Settings settings, @Nullable XPackLicenseState licenseState, ClusterService clusterService) {
+        this.clusterService = clusterService;
+        this.enabled = XPackSettings.SNAPSHOT_LIFECYCLE_ENABLED.get(settings);
+        this.licenseState = licenseState;
+    }
+
+    @Override
+    public String name() {
+        return XPackField.SNAPSHOT_LIFECYCLE;
+    }
+
+    @Override
+    public boolean available() {
+        return licenseState != null && licenseState.isIndexLifecycleAllowed();
+    }
+
+    @Override
+    public boolean enabled() {
+        return enabled;
+    }
+
+    @Override
+    public Map<String, Object> nativeCodeInfo() {
+        return null;
+    }
+
+    @Override
+    public void usage(ActionListener<Usage> listener) {
+        final ClusterState state = clusterService.state();
+        boolean available = licenseState.isIndexLifecycleAllowed();
+        final SnapshotLifecycleMetadata slmMeta = state.metaData().custom(SnapshotLifecycleMetadata.TYPE);
+        final SLMFeatureSetUsage usage = new SLMFeatureSetUsage(available, enabled,
+            slmMeta == null ? null : slmMeta.getStats());
+        listener.onResponse(usage);
+    }
+
+}