[Backport 2.x] Create SystemIndexRegistry with helper method matchesSystemIndex

CHANGELOG.md

@@ -12,6 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add batching supported processor base type AbstractBatchingProcessor ([#14554](https://github.com/opensearch-project/OpenSearch/pull/14554))
 - Fix race condition while parsing derived fields from search definition ([14445](https://github.com/opensearch-project/OpenSearch/pull/14445))
 - Add allowlist setting for ingest-common and search-pipeline-common processors ([#14439](https://github.com/opensearch-project/OpenSearch/issues/14439))
+- Create SystemIndexRegistry with helper method matchesSystemIndex ([#14415](https://github.com/opensearch-project/OpenSearch/pull/14415))
 
 ### Dependencies
 - Update to Apache Lucene 9.11.1 ([#14042](https://github.com/opensearch-project/OpenSearch/pull/14042), [#14576](https://github.com/opensearch-project/OpenSearch/pull/14576))

server/src/main/java/org/opensearch/indices/SystemIndexDescriptor.java

@@ -33,15 +33,17 @@
 package org.opensearch.indices;
 
 import org.apache.lucene.util.automaton.CharacterRunAutomaton;
+import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.common.regex.Regex;
 
 import java.util.Objects;
 
 /**
  * Describes a system index. Provides the information required to create and maintain the system index.
  *
- * @opensearch.internal
+ * @opensearch.api
  */
+@PublicApi(since = "2.16.0")
 public class SystemIndexDescriptor {
     private final String indexPattern;
     private final String description;

server/src/main/java/org/opensearch/indices/SystemIndexRegistry.java

@@ -0,0 +1,130 @@
+/*
+ * 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.indices;
+
+import org.apache.lucene.util.automaton.Automaton;
+import org.apache.lucene.util.automaton.Operations;
+import org.opensearch.common.annotation.ExperimentalApi;
+import org.opensearch.common.collect.Tuple;
+import org.opensearch.common.regex.Regex;
+import org.opensearch.tasks.TaskResultsService;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static java.util.Collections.singletonList;
+import static java.util.Collections.singletonMap;
+import static java.util.Collections.unmodifiableMap;
+import static org.opensearch.tasks.TaskResultsService.TASK_INDEX;
+
+/**
+ * This class holds the {@link SystemIndexDescriptor} objects that represent system indices the
+ * node knows about. This class also contains static methods that identify if index expressions match
+ * registered system index patterns
+ *
+ * @opensearch.api
+ */
+@ExperimentalApi
+public class SystemIndexRegistry {
+    private static final SystemIndexDescriptor TASK_INDEX_DESCRIPTOR = new SystemIndexDescriptor(TASK_INDEX + "*", "Task Result Index");
+    private static final Map<String, Collection<SystemIndexDescriptor>> SERVER_SYSTEM_INDEX_DESCRIPTORS = singletonMap(
+        TaskResultsService.class.getName(),
+        singletonList(TASK_INDEX_DESCRIPTOR)
+    );
+
+    private volatile static String[] SYSTEM_INDEX_PATTERNS = new String[0];
+    volatile static Collection<SystemIndexDescriptor> SYSTEM_INDEX_DESCRIPTORS = Collections.emptyList();
+
+    static void register(Map<String, Collection<SystemIndexDescriptor>> pluginAndModulesDescriptors) {
+        final Map<String, Collection<SystemIndexDescriptor>> descriptorsMap = buildSystemIndexDescriptorMap(pluginAndModulesDescriptors);
+        checkForOverlappingPatterns(descriptorsMap);
+        List<SystemIndexDescriptor> descriptors = pluginAndModulesDescriptors.values()
+            .stream()
+            .flatMap(Collection::stream)
+            .collect(Collectors.toList());
+        descriptors.add(TASK_INDEX_DESCRIPTOR);
+
+        SYSTEM_INDEX_DESCRIPTORS = descriptors.stream().collect(Collectors.toUnmodifiableList());
+        SYSTEM_INDEX_PATTERNS = descriptors.stream().map(SystemIndexDescriptor::getIndexPattern).toArray(String[]::new);
+    }
+
+    public static List<String> matchesSystemIndexPattern(String... indexExpressions) {
+        return Arrays.stream(indexExpressions)
+            .filter(pattern -> Regex.simpleMatch(SYSTEM_INDEX_PATTERNS, pattern))
+            .collect(Collectors.toList());
+    }
+
+    /**
+     * Given a collection of {@link SystemIndexDescriptor}s and their sources, checks to see if the index patterns of the listed
+     * descriptors overlap with any of the other patterns. If any do, throws an exception.
+     *
+     * @param sourceToDescriptors A map of source (plugin) names to the SystemIndexDescriptors they provide.
+     * @throws IllegalStateException Thrown if any of the index patterns overlaps with another.
+     */
+    static void checkForOverlappingPatterns(Map<String, Collection<SystemIndexDescriptor>> sourceToDescriptors) {
+        List<Tuple<String, SystemIndexDescriptor>> sourceDescriptorPair = sourceToDescriptors.entrySet()
+            .stream()
+            .flatMap(entry -> entry.getValue().stream().map(descriptor -> new Tuple<>(entry.getKey(), descriptor)))
+            .sorted(Comparator.comparing(d -> d.v1() + ":" + d.v2().getIndexPattern())) // Consistent ordering -> consistent error message
+            .collect(Collectors.toList());
+
+        // This is O(n^2) with the number of system index descriptors, and each check is quadratic with the number of states in the
+        // automaton, but the absolute number of system index descriptors should be quite small (~10s at most), and the number of states
+        // per pattern should be low as well. If these assumptions change, this might need to be reworked.
+        sourceDescriptorPair.forEach(descriptorToCheck -> {
+            List<Tuple<String, SystemIndexDescriptor>> descriptorsMatchingThisPattern = sourceDescriptorPair.stream()
+
+                .filter(d -> descriptorToCheck.v2() != d.v2()) // Exclude the pattern currently being checked
+                .filter(d -> overlaps(descriptorToCheck.v2(), d.v2()))
+                .collect(Collectors.toList());
+            if (descriptorsMatchingThisPattern.isEmpty() == false) {
+                throw new IllegalStateException(
+                    "a system index descriptor ["
+                        + descriptorToCheck.v2()
+                        + "] from ["
+                        + descriptorToCheck.v1()
+                        + "] overlaps with other system index descriptors: ["
+                        + descriptorsMatchingThisPattern.stream()
+                            .map(descriptor -> descriptor.v2() + " from [" + descriptor.v1() + "]")
+                            .collect(Collectors.joining(", "))
+                );
+            }
+        });
+    }
+
+    private static boolean overlaps(SystemIndexDescriptor a1, SystemIndexDescriptor a2) {
+        Automaton a1Automaton = Regex.simpleMatchToAutomaton(a1.getIndexPattern());
+        Automaton a2Automaton = Regex.simpleMatchToAutomaton(a2.getIndexPattern());
+        return Operations.isEmpty(Operations.intersection(a1Automaton, a2Automaton)) == false;
+    }
+
+    private static Map<String, Collection<SystemIndexDescriptor>> buildSystemIndexDescriptorMap(
+        Map<String, Collection<SystemIndexDescriptor>> pluginAndModulesMap
+    ) {
+        final Map<String, Collection<SystemIndexDescriptor>> map = new HashMap<>(
+            pluginAndModulesMap.size() + SERVER_SYSTEM_INDEX_DESCRIPTORS.size()
+        );
+        map.putAll(pluginAndModulesMap);
+        // put the server items last since we expect less of them
+        SERVER_SYSTEM_INDEX_DESCRIPTORS.forEach((source, descriptors) -> {
+            if (map.putIfAbsent(source, descriptors) != null) {
+                throw new IllegalArgumentException(
+                    "plugin or module attempted to define the same source [" + source + "] as a built-in system index"
+                );
+            }
+        });
+        return unmodifiableMap(map);
+    }
+}

server/src/main/java/org/opensearch/indices/SystemIndices.java

@@ -40,25 +40,15 @@
 import org.apache.lucene.util.automaton.MinimizationOperations;
 import org.apache.lucene.util.automaton.Operations;
 import org.opensearch.common.Nullable;
-import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.regex.Regex;
 import org.opensearch.core.index.Index;
-import org.opensearch.tasks.TaskResultsService;
 
 import java.util.Collection;
-import java.util.Comparator;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.stream.Collectors;
 
-import static java.util.Collections.singletonList;
-import static java.util.Collections.singletonMap;
-import static java.util.Collections.unmodifiableList;
-import static java.util.Collections.unmodifiableMap;
-import static org.opensearch.tasks.TaskResultsService.TASK_INDEX;
-
 /**
  * This class holds the {@link SystemIndexDescriptor} objects that represent system indices the
  * node knows about. Methods for determining if an index should be a system index are also provided
@@ -69,21 +59,11 @@
 public class SystemIndices {
     private static final Logger logger = LogManager.getLogger(SystemIndices.class);
 
-    private static final Map<String, Collection<SystemIndexDescriptor>> SERVER_SYSTEM_INDEX_DESCRIPTORS = singletonMap(
-        TaskResultsService.class.getName(),
-        singletonList(new SystemIndexDescriptor(TASK_INDEX + "*", "Task Result Index"))
-    );
-
     private final CharacterRunAutomaton runAutomaton;
-    private final Collection<SystemIndexDescriptor> systemIndexDescriptors;
 
     public SystemIndices(Map<String, Collection<SystemIndexDescriptor>> pluginAndModulesDescriptors) {
-        final Map<String, Collection<SystemIndexDescriptor>> descriptorsMap = buildSystemIndexDescriptorMap(pluginAndModulesDescriptors);
-        checkForOverlappingPatterns(descriptorsMap);
-        this.systemIndexDescriptors = unmodifiableList(
-            descriptorsMap.values().stream().flatMap(Collection::stream).collect(Collectors.toList())
-        );
-        this.runAutomaton = buildCharacterRunAutomaton(systemIndexDescriptors);
+        SystemIndexRegistry.register(pluginAndModulesDescriptors);
+        this.runAutomaton = buildCharacterRunAutomaton(SystemIndexRegistry.SYSTEM_INDEX_DESCRIPTORS);
     }
 
     /**
@@ -111,7 +91,7 @@ public boolean isSystemIndex(String indexName) {
      * @throws IllegalStateException if multiple descriptors match the name
      */
     public @Nullable SystemIndexDescriptor findMatchingDescriptor(String name) {
-        final List<SystemIndexDescriptor> matchingDescriptors = systemIndexDescriptors.stream()
+        final List<SystemIndexDescriptor> matchingDescriptors = SystemIndexRegistry.SYSTEM_INDEX_DESCRIPTORS.stream()
             .filter(descriptor -> descriptor.matchesIndexPattern(name))
             .collect(Collectors.toList());
 
@@ -168,66 +148,4 @@ private static CharacterRunAutomaton buildCharacterRunAutomaton(Collection<Syste
             .reduce(Operations::union);
         return new CharacterRunAutomaton(MinimizationOperations.minimize(automaton.orElse(Automata.makeEmpty()), Integer.MAX_VALUE));
     }
-
-    /**
-     * Given a collection of {@link SystemIndexDescriptor}s and their sources, checks to see if the index patterns of the listed
-     * descriptors overlap with any of the other patterns. If any do, throws an exception.
-     *
-     * @param sourceToDescriptors A map of source (plugin) names to the SystemIndexDescriptors they provide.
-     * @throws IllegalStateException Thrown if any of the index patterns overlaps with another.
-     */
-    static void checkForOverlappingPatterns(Map<String, Collection<SystemIndexDescriptor>> sourceToDescriptors) {
-        List<Tuple<String, SystemIndexDescriptor>> sourceDescriptorPair = sourceToDescriptors.entrySet()
-            .stream()
-            .flatMap(entry -> entry.getValue().stream().map(descriptor -> new Tuple<>(entry.getKey(), descriptor)))
-            .sorted(Comparator.comparing(d -> d.v1() + ":" + d.v2().getIndexPattern())) // Consistent ordering -> consistent error message
-            .collect(Collectors.toList());
-
-        // This is O(n^2) with the number of system index descriptors, and each check is quadratic with the number of states in the
-        // automaton, but the absolute number of system index descriptors should be quite small (~10s at most), and the number of states
-        // per pattern should be low as well. If these assumptions change, this might need to be reworked.
-        sourceDescriptorPair.forEach(descriptorToCheck -> {
-            List<Tuple<String, SystemIndexDescriptor>> descriptorsMatchingThisPattern = sourceDescriptorPair.stream()
-
-                .filter(d -> descriptorToCheck.v2() != d.v2()) // Exclude the pattern currently being checked
-                .filter(d -> overlaps(descriptorToCheck.v2(), d.v2()))
-                .collect(Collectors.toList());
-            if (descriptorsMatchingThisPattern.isEmpty() == false) {
-                throw new IllegalStateException(
-                    "a system index descriptor ["
-                        + descriptorToCheck.v2()
-                        + "] from ["
-                        + descriptorToCheck.v1()
-                        + "] overlaps with other system index descriptors: ["
-                        + descriptorsMatchingThisPattern.stream()
-                            .map(descriptor -> descriptor.v2() + " from [" + descriptor.v1() + "]")
-                            .collect(Collectors.joining(", "))
-                );
-            }
-        });
-    }
-
-    private static boolean overlaps(SystemIndexDescriptor a1, SystemIndexDescriptor a2) {
-        Automaton a1Automaton = Regex.simpleMatchToAutomaton(a1.getIndexPattern());
-        Automaton a2Automaton = Regex.simpleMatchToAutomaton(a2.getIndexPattern());
-        return Operations.isEmpty(Operations.intersection(a1Automaton, a2Automaton)) == false;
-    }
-
-    private static Map<String, Collection<SystemIndexDescriptor>> buildSystemIndexDescriptorMap(
-        Map<String, Collection<SystemIndexDescriptor>> pluginAndModulesMap
-    ) {
-        final Map<String, Collection<SystemIndexDescriptor>> map = new HashMap<>(
-            pluginAndModulesMap.size() + SERVER_SYSTEM_INDEX_DESCRIPTORS.size()
-        );
-        map.putAll(pluginAndModulesMap);
-        // put the server items last since we expect less of them
-        SERVER_SYSTEM_INDEX_DESCRIPTORS.forEach((source, descriptors) -> {
-            if (map.putIfAbsent(source, descriptors) != null) {
-                throw new IllegalArgumentException(
-                    "plugin or module attempted to define the same source [" + source + "] as a built-in system index"
-                );
-            }
-        });
-        return unmodifiableMap(map);
-    }
 }

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

@@ -693,6 +693,14 @@ protected Node(
                 repositoriesServiceReference::get,
                 rerouteServiceReference::get
             );
+            final Map<String, Collection<SystemIndexDescriptor>> systemIndexDescriptorMap = Collections.unmodifiableMap(
+                pluginsService.filterPlugins(SystemIndexPlugin.class)
+                    .stream()
+                    .collect(
+                        Collectors.toMap(plugin -> plugin.getClass().getSimpleName(), plugin -> plugin.getSystemIndexDescriptors(settings))
+                    )
+            );
+            final SystemIndices systemIndices = new SystemIndices(systemIndexDescriptorMap);
             final ClusterModule clusterModule = new ClusterModule(
                 settings,
                 clusterService,
@@ -817,15 +825,6 @@ protected Node(
                 .flatMap(m -> m.entrySet().stream())
                 .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
 
-            final Map<String, Collection<SystemIndexDescriptor>> systemIndexDescriptorMap = Collections.unmodifiableMap(
-                pluginsService.filterPlugins(SystemIndexPlugin.class)
-                    .stream()
-                    .collect(
-                        Collectors.toMap(plugin -> plugin.getClass().getSimpleName(), plugin -> plugin.getSystemIndexDescriptors(settings))
-                    )
-            );
-            final SystemIndices systemIndices = new SystemIndices(systemIndexDescriptorMap);
-
             final RerouteService rerouteService = new BatchedRerouteService(clusterService, clusterModule.getAllocationService()::reroute);
             rerouteServiceReference.set(rerouteService);
             clusterService.setRerouteService(rerouteService);