Added integration test for snapshots metrics

Signed-off-by: Smit Patel <[email protected]>

README.md

@@ -145,6 +145,13 @@ To disable exporting cluster settings use:
 prometheus.cluster.settings: false
 ```
 
+#### Snapshot metrics
+
+To enable exporting snapshot metrics use:
+```
+prometheus.snapshots: true
+```
+
 #### Nodes filter
 
 Metrics include statistics about individual OpenSearch nodes.

build.gradle

@@ -1,3 +1,4 @@
+import org.opensearch.gradle.PropertyNormalization
 import org.opensearch.gradle.test.RestIntegTestTask
 
 import java.util.regex.Matcher
@@ -124,8 +125,13 @@ tasks.named("check").configure { dependsOn(integTest) }
 // Temporary disable task :testingConventions
 testingConventions.enabled = false
 
+// Directory for snapshot repository
+File repositoryDir = new File(project.buildDir, "shared-repository")
+
 testClusters.all {
     numberOfNodes = 2
+    // Configuring repo path for 'fs' type snapshot repository
+    setting 'path.repo', "${repositoryDir.absolutePath}", PropertyNormalization.IGNORE_VALUE
 
     // It seems cluster name can not be customized here. It gives an error:
     // Testclusters does not allow the following settings to be changed:[cluster.name] for node{::yamlRestTest-0}

src/main/java/org/compuscene/metrics/prometheus/PrometheusSettings.java

@@ -55,23 +55,23 @@ public enum INDEX_FILTER_OPTIONS {
     static String PROMETHEUS_SELECTED_OPTION_KEY = "prometheus.indices_filter.selected_option";
 
     /**
-     * This setting is used configure weather to expose cluster settings metrics or not. The default value is true.
+     * This setting is used configure whether to expose cluster settings metrics or not. The default value is true.
      * Can be configured in opensearch.yml file or update dynamically under key {@link #PROMETHEUS_CLUSTER_SETTINGS_KEY}.
      */
     public static final Setting<Boolean> PROMETHEUS_CLUSTER_SETTINGS =
             Setting.boolSetting(PROMETHEUS_CLUSTER_SETTINGS_KEY, true,
                     Setting.Property.Dynamic, Setting.Property.NodeScope);
 
     /**
-     * This setting is used configure weather to expose low level index metrics or not. The default value is true.
+     * This setting is used configure whether to expose low level index metrics or not. The default value is true.
      * Can be configured in opensearch.yml file or update dynamically under key {@link #PROMETHEUS_INDICES_KEY}.
      */
     public static final Setting<Boolean> PROMETHEUS_INDICES =
             Setting.boolSetting(PROMETHEUS_INDICES_KEY, true,
                     Setting.Property.Dynamic, Setting.Property.NodeScope);
 
     /**
-     * This setting is used configure weather to expose snapshot metrics or not. The default value is false.
+     * This setting is used configure whether to expose snapshot metrics or not. The default value is false.
      * Can be configured in opensearch.yml file or update dynamically under key {@link #PROMETHEUS_SNAPSHOTS_KEY}.
      */
     public static final Setting<Boolean> PROMETHEUS_SNAPSHOTS =

src/main/java/org/opensearch/action/SnapshotsResponse.java

@@ -23,6 +23,7 @@
 import org.opensearch.snapshots.SnapshotInfo;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
@@ -39,16 +40,14 @@ public class SnapshotsResponse extends ActionResponse {
      */
     public SnapshotsResponse(StreamInput in) throws IOException {
         super(in);
-        snapshotInfos = in.readList(SnapshotInfo::new);
+        snapshotInfos = Collections.synchronizedList(in.readList(SnapshotInfo::new));
     }
 
     /**
      * A constructor.
-     *
-     * @param snapshotInfos A list of {@link SnapshotInfo} objects to initialize the instance with.
      */
-    public SnapshotsResponse(List<SnapshotInfo> snapshotInfos) {
-        this.snapshotInfos = Collections.unmodifiableList(snapshotInfos);
+    public SnapshotsResponse() {
+        this.snapshotInfos = Collections.synchronizedList(new ArrayList<>());
     }
 
     /**
@@ -64,11 +63,17 @@ public void writeTo(StreamOutput out) throws IOException {
 
     /**
      * Getter for {@code snapshotInfos} list.
-     * The returned list is unmodifiable to ensure immutability.
      *
      * @return the list of {@link SnapshotInfo} objects
      */
     public List<SnapshotInfo> getSnapshotInfos() {
         return snapshotInfos;
     }
-}
+
+    /**
+     * Adds {@code snapshotInfosToAdd} to the {@code snapshotInfos} list.
+     */
+    public void addSnapshotInfos(List<SnapshotInfo> snapshotInfosToAdd) {
+        snapshotInfos.addAll(snapshotInfosToAdd);
+    }
+}

src/main/java/org/opensearch/action/TransportNodePrometheusMetricsAction.java

@@ -40,19 +40,17 @@
 import org.opensearch.action.support.HandledTransportAction;
 import org.opensearch.client.Client;
 import org.opensearch.client.Requests;
+import org.opensearch.cluster.metadata.RepositoryMetadata;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.action.ActionFuture;
 import org.opensearch.common.inject.Inject;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.core.action.ActionListener;
-import org.opensearch.snapshots.SnapshotInfo;
 import org.opensearch.tasks.Task;
 import org.opensearch.transport.TransportService;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.concurrent.ExecutionException;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.stream.Collectors;
 
 /**
@@ -111,7 +109,10 @@ private class AsyncAction {
         private NodesStatsResponse nodesStatsResponse = null;
         private IndicesStatsResponse indicesStatsResponse = null;
         private ClusterStateResponse clusterStateResponse = null;
-        private SnapshotsResponse snapshotsResponse = null;
+        private final Queue<String> snapshotRepositories = new ConcurrentLinkedQueue<>();
+        private final int maxSnapshotRepositoriesToBeFetched = 5;
+        private volatile int snapshotRepositoriesFetchedCount = 0;
+        private final SnapshotsResponse snapshotsResponse = new SnapshotsResponse();
 
         // read the state of prometheus dynamic settings only once at the beginning of the async request
         private final boolean isPrometheusIndices = prometheusSettings.getPrometheusIndices();
@@ -176,22 +177,14 @@ private void gatherRequests() {
             new ActionListener<GetRepositoriesResponse>() {
                 @Override
                 public void onResponse(GetRepositoriesResponse response) {
-                    List<ActionFuture<GetSnapshotsResponse>> snapshotsResponseFutures = response.repositories().stream()
-                            .map(metadata -> new GetSnapshotsRequest(metadata.name()))
-                            .map(snapshotsRequest -> client.admin().cluster().getSnapshots(snapshotsRequest))
-                            .collect(Collectors.toList());
-                    List<SnapshotInfo> snapshotInfos = new ArrayList<>();
-                    for (ActionFuture<GetSnapshotsResponse> snapshotsResponseFuture : snapshotsResponseFutures) {
-                        try {
-                            GetSnapshotsResponse getSnapshotsResponse = snapshotsResponseFuture.get();
-                            snapshotInfos.addAll(getSnapshotsResponse.getSnapshots());
-                        } catch (InterruptedException | ExecutionException e) {
-                            listener.onFailure(new OpenSearchException("Get snapshots request failed", e));
-                            return;
-                        }
+                    if (response.repositories().isEmpty()) {
+                        gatherRequests();
+                        return;
                     }
-                    snapshotsResponse = new SnapshotsResponse(snapshotInfos);
-                    gatherRequests();
+                    snapshotRepositories.addAll(response.repositories().stream()
+                            .map(RepositoryMetadata::name).collect(Collectors.toList()));
+                    String snapshotRepository = snapshotRepositories.poll();
+                    client.admin().cluster().getSnapshots(new GetSnapshotsRequest(snapshotRepository), snapshotsResponseActionListener);
                 }
 
                 @Override
@@ -200,6 +193,27 @@ public void onFailure(Exception e) {
                 }
             };
 
+        private final ActionListener<GetSnapshotsResponse> snapshotsResponseActionListener =
+            new ActionListener<GetSnapshotsResponse>() {
+                @Override
+                public void onResponse(GetSnapshotsResponse response) {
+                    snapshotsResponse.addSnapshotInfos(response.getSnapshots());
+                    snapshotRepositoriesFetchedCount++;
+                    if (snapshotRepositories.isEmpty() || snapshotRepositoriesFetchedCount >= maxSnapshotRepositoriesToBeFetched) {
+                        gatherRequests();
+                        return;
+                    }
+                    // Fetch the snapshots for the next repository in the queue
+                    String snapshotRepository = snapshotRepositories.poll();
+                    client.admin().cluster().getSnapshots(new GetSnapshotsRequest(snapshotRepository), snapshotsResponseActionListener);
+                }
+
+                @Override
+                public void onFailure(Exception e) {
+                    listener.onFailure(new OpenSearchException("Get snapshots request failed", e));
+                }
+            };
+
         private final ActionListener<ClusterStateResponse> clusterStateResponseActionListener =
             new ActionListener<ClusterStateResponse>() {
                 @Override

src/yamlRestTest/resources/rest-api-spec/test/70_10_snapshots_metrics.yml

@@ -0,0 +1,50 @@
+---
+"Verify snapshots metrics enabled":
+
+  # Create 'fs' snapshot repository
+  - do:
+      snapshot.create_repository:
+        repository: test_repo_get_1
+        body:
+          type: fs
+          settings:
+            location: "test_repo_get_1_loc"
+
+  - do:
+      snapshot.get_repository: { }
+
+  - is_true: test_repo_get_1
+
+  # Enable snapshots metrics
+  - do:
+      cluster.put_settings:
+        body:
+          persistent:
+            prometheus.snapshots: "true"
+        flat_settings: true
+
+  - match: { persistent: { prometheus.snapshots: "true" } }
+
+  # Create snapshot
+  - do:
+      snapshot.create:
+        repository: test_repo_get_1
+        snapshot: test_snapshot_1
+        wait_for_completion: true
+
+  - match: { snapshot.snapshot: test_snapshot_1 }
+  - match: { snapshot.state : SUCCESS }
+
+  # Fetch and verify metrics
+  - do:
+      prometheus.metrics: {}
+
+  - match:
+      $body: |
+        /.*
+        \# \s* HELP \s+ opensearch_min_snapshot_age \s+.*\n
+        \# \s* TYPE \s+ opensearch_min_snapshot_age \s+ gauge\n
+        opensearch_min_snapshot_age\{
+          cluster="yamlRestTest",sm_policy="adhoc",
+        \}\s+\d+\.\d+\n
+        .*/