Add basic searchable snapshots usage information (#58828) (#59160)

Adds super basic usage information for searchable snapshots, to be extended later.

Backport of #58828

docs/reference/rest-api/info.asciidoc

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

docs/reference/rest-api/usage.asciidoc

@@ -262,6 +262,11 @@ GET /_xpack/usage
     "available" : true,
     "enabled" : true
   },
+  "searchable_snapshots" : {
+    "available" : true,
+    "enabled" : true,
+    "indices_count" : 0
+  },
   "frozen_indices" : {
     "available" : true,
     "enabled" : true,

x-pack/plugin/core/src/main/java/org/elasticsearch/license/XPackLicenseState.java

@@ -93,7 +93,9 @@ public class XPackLicenseState {
 
         SPATIAL_GEO_GRID(OperationMode.GOLD, true),
 
-        ANALYTICS(OperationMode.MISSING, true);
+        ANALYTICS(OperationMode.MISSING, true),
+
+        SEARCHABLE_SNAPSHOTS(OperationMode.PLATINUM, true);
 
         final OperationMode minimumOperationMode;
         final boolean needsActive;

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

@@ -192,6 +192,7 @@ import org.elasticsearch.xpack.core.rollup.job.RollupJobStatus;
 import org.elasticsearch.xpack.core.async.DeleteAsyncResultAction;
 import org.elasticsearch.xpack.core.search.action.GetAsyncSearchAction;
 import org.elasticsearch.xpack.core.search.action.SubmitAsyncSearchAction;
+import org.elasticsearch.xpack.core.searchablesnapshots.SearchableSnapshotFeatureSetUsage;
 import org.elasticsearch.xpack.core.security.SecurityFeatureSetUsage;
 import org.elasticsearch.xpack.core.security.SecurityField;
 import org.elasticsearch.xpack.core.security.SecuritySettings;
@@ -631,7 +632,10 @@ public class XPackClientPlugin extends Plugin implements ActionPlugin, NetworkPl
                 // analytics
                 new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.ANALYTICS, AnalyticsFeatureSetUsage::new),
                 // Enrich
-                new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.ENRICH, EnrichFeatureSet.Usage::new)
+                new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.ENRICH, EnrichFeatureSet.Usage::new),
+                // Searchable snapshots
+                new NamedWriteableRegistry.Entry(XPackFeatureSet.Usage.class, XPackField.SEARCHABLE_SNAPSHOTS,
+                    SearchableSnapshotFeatureSetUsage::new)
             ).stream(),
             MlEvaluationNamedXContentProvider.getNamedWriteables().stream()
         ).collect(toList());

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

@@ -57,6 +57,8 @@ public final class XPackField {
     public static final String ENRICH = "enrich";
     /** Name constant for the constant-keyword plugin. */
     public static final String CONSTANT_KEYWORD = "constant_keyword";
+    /** Name constant for the searchable snapshots feature. */
+    public static final String SEARCHABLE_SNAPSHOTS = "searchable_snapshots";
 
     private XPackField() {}
 

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

@@ -0,0 +1,74 @@
+/*
+ * 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.searchablesnapshots;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.xpack.core.XPackFeatureSet;
+import org.elasticsearch.xpack.core.XPackField;
+
+import java.io.IOException;
+import java.util.Objects;
+
+public class SearchableSnapshotFeatureSetUsage extends XPackFeatureSet.Usage {
+
+    private final int numberOfSearchableSnapshotIndices;
+
+    public SearchableSnapshotFeatureSetUsage(StreamInput input) throws IOException {
+        super(input);
+        numberOfSearchableSnapshotIndices = input.readVInt();
+    }
+
+    @Override
+    public Version getMinimalSupportedVersion() {
+        return Version.V_7_9_0;
+    }
+
+    @Override
+    public void writeTo(StreamOutput out) throws IOException {
+        super.writeTo(out);
+        out.writeVInt(numberOfSearchableSnapshotIndices);
+    }
+
+    public SearchableSnapshotFeatureSetUsage(boolean available,
+                                             int numberOfSearchableSnapshotIndices) {
+        super(XPackField.SEARCHABLE_SNAPSHOTS, available, true);
+        this.numberOfSearchableSnapshotIndices = numberOfSearchableSnapshotIndices;
+    }
+
+    @Override
+    protected void innerXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
+        super.innerXContent(builder, params);
+        builder.field("indices_count", numberOfSearchableSnapshotIndices);
+    }
+
+    public int getNumberOfSearchableSnapshotIndices() {
+        return numberOfSearchableSnapshotIndices;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(available, enabled, numberOfSearchableSnapshotIndices);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        SearchableSnapshotFeatureSetUsage other = (SearchableSnapshotFeatureSetUsage) obj;
+        return Objects.equals(available, other.available) &&
+            Objects.equals(enabled, other.enabled) &&
+            Objects.equals(numberOfSearchableSnapshotIndices, other.numberOfSearchableSnapshotIndices);
+    }
+}

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

@@ -0,0 +1,69 @@
+/*
+ * 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.searchablesnapshots;
+
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.metadata.IndexMetadata;
+import org.elasticsearch.cluster.service.ClusterService;
+import org.elasticsearch.common.Nullable;
+import org.elasticsearch.common.inject.Inject;
+import org.elasticsearch.license.XPackLicenseState;
+import org.elasticsearch.xpack.core.XPackFeatureSet;
+import org.elasticsearch.xpack.core.XPackField;
+import org.elasticsearch.xpack.searchablesnapshots.SearchableSnapshotsConstants;
+
+import java.util.Map;
+
+public class SearchableSnapshotsFeatureSet implements XPackFeatureSet {
+
+    private final XPackLicenseState licenseState;
+    private final ClusterService clusterService;
+
+    @Inject
+    public SearchableSnapshotsFeatureSet(@Nullable XPackLicenseState licenseState, ClusterService clusterService) {
+        this.licenseState = licenseState;
+        this.clusterService = clusterService;
+    }
+
+    @Override
+    public String name() {
+        return XPackField.SEARCHABLE_SNAPSHOTS;
+    }
+
+    @Override
+    public boolean available() {
+        return licenseState.isAllowed(XPackLicenseState.Feature.SEARCHABLE_SNAPSHOTS);
+    }
+
+    @Override
+    public boolean enabled() {
+        return true;
+    }
+
+    @Override
+    public Map<String, Object> nativeCodeInfo() {
+        return null;
+    }
+
+    @Override
+    public void usage(ActionListener<XPackFeatureSet.Usage> listener) {
+        ClusterState state = clusterService.state();
+        int numSnapIndices = 0;
+        for (IndexMetadata indexMetadata : state.metadata()) {
+            if (SearchableSnapshotsConstants.isSearchableSnapshotStore(indexMetadata.getSettings())) {
+                numSnapIndices++;
+            }
+        }
+        listener.onResponse(
+            new SearchableSnapshotFeatureSetUsage(
+                available(),
+                numSnapIndices
+            )
+        );
+    }
+}

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/searchablesnapshots/SearchableSnapshotsFeatureSetUsageTests.java

@@ -0,0 +1,43 @@
+/*
+ * 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.searchablesnapshots;
+
+import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.test.AbstractWireSerializingTestCase;
+
+import java.io.IOException;
+
+public class SearchableSnapshotsFeatureSetUsageTests extends AbstractWireSerializingTestCase<SearchableSnapshotFeatureSetUsage> {
+
+    @Override
+    protected SearchableSnapshotFeatureSetUsage createTestInstance() {
+        boolean available = randomBoolean();
+        return new SearchableSnapshotFeatureSetUsage(available, randomIntBetween(0, 100000));
+    }
+
+    @Override
+    protected SearchableSnapshotFeatureSetUsage mutateInstance(SearchableSnapshotFeatureSetUsage instance) throws IOException {
+        boolean available = instance.available();
+        int numSearchableSnapshotIndices = instance.getNumberOfSearchableSnapshotIndices();
+        switch (between(0, 1)) {
+            case 0:
+                available = available == false;
+                break;
+            case 1:
+                numSearchableSnapshotIndices = randomValueOtherThan(numSearchableSnapshotIndices, () -> randomIntBetween(0, 100000));
+                break;
+            default:
+                throw new AssertionError("Illegal randomisation branch");
+        }
+        return new SearchableSnapshotFeatureSetUsage(available, numSearchableSnapshotIndices);
+    }
+
+    @Override
+    protected Writeable.Reader<SearchableSnapshotFeatureSetUsage> instanceReader() {
+        return SearchableSnapshotFeatureSetUsage::new;
+    }
+
+}

x-pack/plugin/searchable-snapshots/src/main/java/org/elasticsearch/xpack/searchablesnapshots/SearchableSnapshots.java

@@ -13,6 +13,7 @@ import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
 import org.elasticsearch.cluster.routing.allocation.ExistingShardsAllocator;
 import org.elasticsearch.cluster.service.ClusterService;
+import org.elasticsearch.common.inject.Module;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.settings.ClusterSettings;
 import org.elasticsearch.common.settings.IndexScopedSettings;
@@ -31,7 +32,6 @@ import org.elasticsearch.index.engine.EngineFactory;
 import org.elasticsearch.index.engine.ReadOnlyEngine;
 import org.elasticsearch.index.store.SearchableSnapshotDirectory;
 import org.elasticsearch.index.translog.TranslogStats;
-import org.elasticsearch.license.License;
 import org.elasticsearch.license.LicenseUtils;
 import org.elasticsearch.license.XPackLicenseState;
 import org.elasticsearch.plugins.ActionPlugin;
@@ -47,7 +47,9 @@ import org.elasticsearch.threadpool.ExecutorBuilder;
 import org.elasticsearch.threadpool.ScalingExecutorBuilder;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.watcher.ResourceWatcherService;
+import org.elasticsearch.xpack.core.XPackPlugin;
 import org.elasticsearch.xpack.core.searchablesnapshots.MountSearchableSnapshotAction;
+import org.elasticsearch.xpack.core.searchablesnapshots.SearchableSnapshotsFeatureSet;
 import org.elasticsearch.xpack.searchablesnapshots.action.ClearSearchableSnapshotsCacheAction;
 import org.elasticsearch.xpack.searchablesnapshots.action.RepositoryStatsAction;
 import org.elasticsearch.xpack.searchablesnapshots.action.SearchableSnapshotsStatsAction;
@@ -137,12 +139,15 @@ public class SearchableSnapshots extends Plugin implements IndexStorePlugin, Eng
     private final SetOnce<ThreadPool> threadPool = new SetOnce<>();
     private final Settings settings;
 
+    private final boolean transportClientMode;
+
     public SearchableSnapshots(final Settings settings) {
         this.settings = settings;
+        this.transportClientMode = XPackPlugin.transportClientMode(settings);
     }
 
     public static void ensureValidLicense(XPackLicenseState licenseState) {
-        if (licenseState.isAllowedByLicense(License.OperationMode.PLATINUM) == false) {
+        if (licenseState.isAllowed(XPackLicenseState.Feature.SEARCHABLE_SNAPSHOTS) == false) {
             throw LicenseUtils.newComplianceException("searchable-snapshots");
         }
     }
@@ -196,6 +201,19 @@ public class SearchableSnapshots extends Plugin implements IndexStorePlugin, Eng
         }
     }
 
+    @Override
+    public Collection<Module> createGuiceModules() {
+        if (SEARCHABLE_SNAPSHOTS_FEATURE_ENABLED) {
+            if (transportClientMode) {
+                return Collections.emptyList();
+            }
+
+            return Collections.singleton(b -> XPackPlugin.bindFeatureSet(b, SearchableSnapshotsFeatureSet.class));
+        } else {
+            return org.elasticsearch.common.collect.List.of();
+        }
+    }
+
     @Override
     public void onIndexModule(IndexModule indexModule) {
         if (SearchableSnapshotsConstants.isSearchableSnapshotStore(indexModule.getSettings())) {

x-pack/plugin/src/test/resources/rest-api-spec/test/searchable_snapshots/10_usage.yml

@@ -0,0 +1,96 @@
+---
+setup:
+
+  - do:
+      indices.create:
+        index: docs
+        body:
+          settings:
+            number_of_shards:   1
+            number_of_replicas: 0
+
+  - do:
+      bulk:
+        body:
+          - index:
+              _index: docs
+              _id:    1
+          - field: foo
+          - index:
+              _index: docs
+              _id:    2
+          - field: bar
+          - index:
+              _index: docs
+              _id:    3
+          - field: baz
+
+  - do:
+      snapshot.create_repository:
+        repository: repository-fs
+        body:
+          type: fs
+          settings:
+            location: "repository-fs"
+
+  # Remove the snapshot if a previous test failed to delete it.
+  # Useful for third party tests that runs the test against a real external service.
+  - do:
+      snapshot.delete:
+        repository: repository-fs
+        snapshot: snapshot
+        ignore: 404
+
+  - do:
+      snapshot.create:
+        repository: repository-fs
+        snapshot: snapshot
+        wait_for_completion: true
+
+  - do:
+      indices.delete:
+        index: docs
+---
+teardown:
+
+  - do:
+      snapshot.delete:
+        repository: repository-fs
+        snapshot: snapshot
+        ignore: 404
+
+  - do:
+      snapshot.delete_repository:
+        repository: repository-fs
+
+---
+"Tests searchable snapshots usage stats":
+  - skip:
+      version: " - 7.8.99"
+      reason:  searchable snapshots usage stats introduced in 7.9.0
+
+  - do:
+      xpack.usage: {}
+
+  - match: { searchable_snapshots.available: true }
+  - match: { searchable_snapshots.enabled: true }
+  - match: { searchable_snapshots.indices_count: 0 }
+
+  - do:
+      searchable_snapshots.mount:
+        repository: repository-fs
+        snapshot: snapshot
+        wait_for_completion: true
+        body:
+          index: docs
+
+  - match: { snapshot.snapshot: snapshot }
+  - match: { snapshot.shards.failed: 0 }
+  - match: { snapshot.shards.successful: 1 }
+
+  - do:
+      xpack.usage: {}
+
+  - match: { searchable_snapshots.available: true }
+  - match: { searchable_snapshots.enabled: true }
+  - match: { searchable_snapshots.indices_count: 1 }