Create SystemIndexRegistry with helper method matchesSystemIndex

CHANGELOG.md

@@ -6,6 +6,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ## [Unreleased 2.x]
 ### Added
 - Add fingerprint ingest processor ([#13724](https://github.com/opensearch-project/OpenSearch/pull/13724))
+- Create new extension point in SystemIndexPlugin for a single plugin to get registered system indices ([#14415](https://github.com/opensearch-project/OpenSearch/pull/14415))
 
 ### Dependencies
 - Bump `org.gradle.test-retry` from 1.5.8 to 1.5.9 ([#13442](https://github.com/opensearch-project/OpenSearch/pull/13442))

server/src/internalClusterTest/java/org/opensearch/plugins/SystemIndexPluginIT.java

@@ -0,0 +1,73 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.plugins;
+
+import org.opensearch.common.settings.Settings;
+import org.opensearch.indices.SystemIndexDescriptor;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Consumer;
+
+import static org.hamcrest.Matchers.containsString;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0, numClientNodes = 0)
+public class SystemIndexPluginIT extends OpenSearchIntegTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> nodePlugins() {
+        return List.of(SystemIndexPlugin1.class, SystemIndexPlugin2.class);
+    }
+
+    public void test2SystemIndexPluginsImplementOnSystemIndices_shouldFail() throws Exception {
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> internalCluster().startNode());
+        assertThat(e.getMessage(), containsString("Cannot have more than one plugin implementing onSystemIndex"));
+    }
+
+}
+
+final class SystemIndexPlugin1 extends Plugin implements SystemIndexPlugin {
+
+    private Map<String, Set<String>> systemIndices;
+
+    public SystemIndexPlugin1() {}
+
+    @Override
+    public Collection<SystemIndexDescriptor> getSystemIndexDescriptors(Settings settings) {
+        final SystemIndexDescriptor systemIndexDescriptor = new SystemIndexDescriptor(".system-index1", "System index 1");
+        return Collections.singletonList(systemIndexDescriptor);
+    }
+
+    @Override
+    public Consumer<Map<String, Set<String>>> onSystemIndices() {
+        return (systemIndices) -> { this.systemIndices = systemIndices; };
+    }
+}
+
+class SystemIndexPlugin2 extends Plugin implements SystemIndexPlugin {
+
+    private Map<String, Set<String>> systemIndices;
+
+    public SystemIndexPlugin2() {}
+
+    @Override
+    public Collection<SystemIndexDescriptor> getSystemIndexDescriptors(Settings settings) {
+        final SystemIndexDescriptor systemIndexDescriptor = new SystemIndexDescriptor(".system-index2", "System index 2");
+        return Collections.singletonList(systemIndexDescriptor);
+    }
+
+    @Override
+    public Consumer<Map<String, Set<String>>> onSystemIndices() {
+        return (systemIndices) -> { this.systemIndices = systemIndices; };
+    }
+}

server/src/main/java/org/opensearch/node/Node.java

@@ -286,6 +286,7 @@
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.UnaryOperator;
 import java.util.stream.Collectors;
@@ -814,15 +815,44 @@ protected Node(
                 .flatMap(m -> m.entrySet().stream())
                 .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
 
+            List<SystemIndexPlugin> systemIndexPlugins = pluginsService.filterPlugins(SystemIndexPlugin.class);
             final Map<String, Collection<SystemIndexDescriptor>> systemIndexDescriptorMap = Collections.unmodifiableMap(
-                pluginsService.filterPlugins(SystemIndexPlugin.class)
-                    .stream()
+                systemIndexPlugins.stream()
                     .collect(
                         Collectors.toMap(plugin -> plugin.getClass().getSimpleName(), plugin -> plugin.getSystemIndexDescriptors(settings))
                     )
             );
             final SystemIndices systemIndices = new SystemIndices(systemIndexDescriptorMap);
 
+            final Map<String, Set<String>> systemIndexMap = Collections.unmodifiableMap(
+                systemIndexPlugins.stream()
+                    .collect(
+                        Collectors.toMap(
+                            plugin -> plugin.getClass().getCanonicalName(),
+                            plugin -> plugin.getSystemIndexDescriptors(settings)
+                                .stream()
+                                .map(SystemIndexDescriptor::getIndexPattern)
+                                .collect(Collectors.toSet())
+                        )
+                    )
+            );
+
+            Consumer<Map<String, Set<String>>> onSystemIndex = null;
+            for (SystemIndexPlugin plugin : systemIndexPlugins) {
+                Consumer<Map<String, Set<String>>> newOnSystemIndex = plugin.onSystemIndices();
+                if (newOnSystemIndex != null) {
+                    logger.debug("Using onSystemIndex from plugin " + plugin.getClass().getCanonicalName());
+                    if (onSystemIndex != null) {
+                        throw new IllegalArgumentException("Cannot have more than one plugin implementing onSystemIndex");
+                    }
+                    onSystemIndex = newOnSystemIndex;
+                }
+            }
+
+            if (onSystemIndex != null) {
+                onSystemIndex.accept(systemIndexMap);
+            }
+
             final RerouteService rerouteService = new BatchedRerouteService(clusterService, clusterModule.getAllocationService()::reroute);
             rerouteServiceReference.set(rerouteService);
             clusterService.setRerouteService(rerouteService);

server/src/main/java/org/opensearch/plugins/SystemIndexPlugin.java

@@ -37,6 +37,9 @@
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Consumer;
 
 /**
  * Plugin for defining system indices. Extends {@link ActionPlugin} because system indices must be accessed via APIs
@@ -55,4 +58,13 @@ public interface SystemIndexPlugin extends ActionPlugin {
     default Collection<SystemIndexDescriptor> getSystemIndexDescriptors(Settings settings) {
         return Collections.emptyList();
     }
+
+    /**
+     * This function passes the registered system indices to a plugin.
+     *
+     * Note: Only one installed plugin may implement onSystemIndices.
+     */
+    default Consumer<Map<String, Set<String>>> onSystemIndices() {
+        return null;
+    }
 }