Remove cluster state initial customs (#32501)

This infrastructure was introduced in #26144 and made obsolete in #30743

server/src/main/java/org/elasticsearch/cluster/ClusterModule.java

@@ -116,23 +116,6 @@ public ClusterModule(Settings settings, ClusterService clusterService, List<Clus
         this.allocationService = new AllocationService(settings, allocationDeciders, shardsAllocator, clusterInfoService);
     }
 
-    public static Map<String, Supplier<ClusterState.Custom>> getClusterStateCustomSuppliers(List<ClusterPlugin> clusterPlugins) {
-        final Map<String, Supplier<ClusterState.Custom>> customSupplier = new HashMap<>();
-        customSupplier.put(SnapshotDeletionsInProgress.TYPE, SnapshotDeletionsInProgress::new);
-        customSupplier.put(RestoreInProgress.TYPE, RestoreInProgress::new);
-        customSupplier.put(SnapshotsInProgress.TYPE, SnapshotsInProgress::new);
-        for (ClusterPlugin plugin : clusterPlugins) {
-            Map<String, Supplier<ClusterState.Custom>> initialCustomSupplier = plugin.getInitialClusterStateCustomSupplier();
-            for (String key : initialCustomSupplier.keySet()) {
-                if (customSupplier.containsKey(key)) {
-                    throw new IllegalStateException("custom supplier key [" + key + "] is registered more than once");
-                }
-            }
-            customSupplier.putAll(initialCustomSupplier);
-        }
-        return Collections.unmodifiableMap(customSupplier);
-    }
-
     public static List<Entry> getNamedWriteables() {
         List<Entry> entries = new ArrayList<>();
         // Cluster State

server/src/main/java/org/elasticsearch/cluster/service/ClusterApplier.java

@@ -39,11 +39,6 @@ public interface ClusterApplier {
      */
     void onNewClusterState(String source, Supplier<ClusterState> clusterStateSupplier, ClusterApplyListener listener);
 
-    /**
-     * Creates a new cluster state builder that is initialized with the cluster name and all initial cluster state customs.
-     */
-    ClusterState.Builder newClusterStateBuilder();
-
     /**
      * Listener for results of cluster state application
      */

server/src/main/java/org/elasticsearch/cluster/service/ClusterApplierService.java

@@ -96,17 +96,14 @@ public class ClusterApplierService extends AbstractLifecycleComponent implements
     private final AtomicReference<ClusterState> state; // last applied state
 
     private NodeConnectionsService nodeConnectionsService;
-    private Supplier<ClusterState.Builder> stateBuilderSupplier;
 
-    public ClusterApplierService(Settings settings, ClusterSettings clusterSettings, ThreadPool threadPool, Supplier<ClusterState
-        .Builder> stateBuilderSupplier) {
+    public ClusterApplierService(Settings settings, ClusterSettings clusterSettings, ThreadPool threadPool) {
         super(settings);
         this.clusterSettings = clusterSettings;
         this.threadPool = threadPool;
         this.state = new AtomicReference<>();
         this.slowTaskLoggingThreshold = CLUSTER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING.get(settings);
         this.localNodeMasterListeners = new LocalNodeMasterListeners(threadPool);
-        this.stateBuilderSupplier = stateBuilderSupplier;
     }
 
     public void setSlowTaskLoggingThreshold(TimeValue slowTaskLoggingThreshold) {
@@ -652,8 +649,4 @@ protected long currentTimeInNanos() {
         return System.nanoTime();
     }
 
-    @Override
-    public ClusterState.Builder newClusterStateBuilder() {
-        return stateBuilderSupplier.get();
-    }
 }

server/src/main/java/org/elasticsearch/cluster/service/ClusterService.java

@@ -42,7 +42,6 @@
 
 import java.util.Collections;
 import java.util.Map;
-import java.util.function.Supplier;
 
 public class ClusterService extends AbstractLifecycleComponent {
 
@@ -59,30 +58,16 @@ public class ClusterService extends AbstractLifecycleComponent {
     private final OperationRouting operationRouting;
 
     private final ClusterSettings clusterSettings;
-    private final Map<String, Supplier<ClusterState.Custom>> initialClusterStateCustoms;
 
-    public ClusterService(Settings settings, ClusterSettings clusterSettings, ThreadPool threadPool,
-                          Map<String, Supplier<ClusterState.Custom>> initialClusterStateCustoms) {
+    public ClusterService(Settings settings, ClusterSettings clusterSettings, ThreadPool threadPool) {
         super(settings);
         this.masterService = new MasterService(settings, threadPool);
         this.operationRouting = new OperationRouting(settings, clusterSettings);
         this.clusterSettings = clusterSettings;
         this.clusterName = ClusterName.CLUSTER_NAME_SETTING.get(settings);
         this.clusterSettings.addSettingsUpdateConsumer(CLUSTER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING,
             this::setSlowTaskLoggingThreshold);
-        this.initialClusterStateCustoms = initialClusterStateCustoms;
-        this.clusterApplierService = new ClusterApplierService(settings, clusterSettings, threadPool, this::newClusterStateBuilder);
-    }
-
-    /**
-     * Creates a new cluster state builder that is initialized with the cluster name and all initial cluster state customs.
-     */
-    public ClusterState.Builder newClusterStateBuilder() {
-        ClusterState.Builder builder = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.get(settings));
-        for (Map.Entry<String, Supplier<ClusterState.Custom>> entry : initialClusterStateCustoms.entrySet()) {
-            builder.putCustom(entry.getKey(), entry.getValue().get());
-        }
-        return builder;
+        this.clusterApplierService = new ClusterApplierService(settings, clusterSettings, threadPool);
     }
 
     private void setSlowTaskLoggingThreshold(TimeValue slowTaskLoggingThreshold) {

server/src/main/java/org/elasticsearch/discovery/single/SingleNodeDiscovery.java

@@ -21,6 +21,7 @@
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.elasticsearch.cluster.ClusterChangedEvent;
+import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.block.ClusterBlocks;
 import org.elasticsearch.cluster.node.DiscoveryNode;
@@ -113,7 +114,7 @@ protected synchronized void doStart() {
     }
 
     protected ClusterState createInitialState(DiscoveryNode localNode) {
-        ClusterState.Builder builder = clusterApplier.newClusterStateBuilder();
+        ClusterState.Builder builder = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.get(settings));
         return builder.nodes(DiscoveryNodes.builder().add(localNode)
                 .localNodeId(localNode.getId())
                 .masterNodeId(localNode.getId())

server/src/main/java/org/elasticsearch/discovery/zen/ZenDiscovery.java

@@ -252,7 +252,7 @@ protected void doStart() {
             // set initial state
             assert committedState.get() == null;
             assert localNode != null;
-            ClusterState.Builder builder = clusterApplier.newClusterStateBuilder();
+            ClusterState.Builder builder = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.get(settings));
             ClusterState initialState = builder
                 .blocks(ClusterBlocks.builder()
                     .addGlobalBlock(STATE_NOT_RECOVERED_BLOCK)

server/src/main/java/org/elasticsearch/gateway/Gateway.java

@@ -23,6 +23,7 @@
 import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.elasticsearch.action.FailedNodeException;
+import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.cluster.metadata.MetaData;
@@ -147,7 +148,7 @@ public void performStateRecovery(final GatewayStateRecoveredListener listener) t
                 metaDataBuilder.transientSettings(),
                 e -> logUnknownSetting("transient", e),
                 (e, ex) -> logInvalidSetting("transient", e, ex)));
-        ClusterState.Builder builder = clusterService.newClusterStateBuilder();
+        ClusterState.Builder builder = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.get(settings));
         builder.metaData(metaDataBuilder);
         listener.onSuccess(builder.build());
     }

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

@@ -349,8 +349,7 @@ protected Node(final Environment environment, Collection<Class<? extends Plugin>
                 getCustomNameResolvers(pluginsService.filterPlugins(DiscoveryPlugin.class)));
 
             List<ClusterPlugin> clusterPlugins = pluginsService.filterPlugins(ClusterPlugin.class);
-            final ClusterService clusterService = new ClusterService(settings, settingsModule.getClusterSettings(), threadPool,
-               ClusterModule.getClusterStateCustomSuppliers(clusterPlugins));
+            final ClusterService clusterService = new ClusterService(settings, settingsModule.getClusterSettings(), threadPool);
             clusterService.addStateApplier(scriptModule.getScriptService());
             resourcesToClose.add(clusterService);
             final IngestService ingestService = new IngestService(settings, threadPool, this.environment,

server/src/main/java/org/elasticsearch/plugins/ClusterPlugin.java

@@ -24,7 +24,6 @@
 import java.util.Map;
 import java.util.function.Supplier;
 
-import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.routing.allocation.allocator.ShardsAllocator;
 import org.elasticsearch.cluster.routing.allocation.decider.AllocationDecider;
 import org.elasticsearch.common.settings.ClusterSettings;
@@ -66,12 +65,4 @@ default Map<String, Supplier<ShardsAllocator>> getShardsAllocators(Settings sett
     default void onNodeStarted() {
     }
 
-    /**
-     * Returns a map of {@link ClusterState.Custom} supplier that should be invoked to initialize the initial clusterstate.
-     * This allows custom clusterstate extensions to be always present and prevents invariants where clusterstates are published
-     * but customs are not initialized.
-     *
-     * TODO: Remove this whole concept of InitialClusterStateCustomSupplier, it's not used anymore
-     */
-    default Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() { return Collections.emptyMap(); }
 }

server/src/test/java/org/elasticsearch/cluster/ClusterModuleTests.java

@@ -63,7 +63,7 @@
 public class ClusterModuleTests extends ModuleTestCase {
     private ClusterInfoService clusterInfoService = EmptyClusterInfoService.INSTANCE;
     private ClusterService clusterService = new ClusterService(Settings.EMPTY,
-        new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS), null, Collections.emptyMap());
+        new ClusterSettings(Settings.EMPTY, ClusterSettings.BUILT_IN_CLUSTER_SETTINGS), null);
     static class FakeAllocationDecider extends AllocationDecider {
         protected FakeAllocationDecider(Settings settings) {
             super(settings);
@@ -202,57 +202,6 @@ public void testAllocationDeciderOrder() {
         }
     }
 
-    public void testCustomSuppliers() {
-        Map<String, Supplier<ClusterState.Custom>> customSuppliers = ClusterModule.getClusterStateCustomSuppliers(Collections.emptyList());
-        assertEquals(3, customSuppliers.size());
-        assertTrue(customSuppliers.containsKey(SnapshotsInProgress.TYPE));
-        assertTrue(customSuppliers.containsKey(SnapshotDeletionsInProgress.TYPE));
-        assertTrue(customSuppliers.containsKey(RestoreInProgress.TYPE));
-
-        customSuppliers = ClusterModule.getClusterStateCustomSuppliers(Collections.singletonList(new ClusterPlugin() {
-            @Override
-            public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
-                return Collections.singletonMap("foo", () -> null);
-            }
-        }));
-        assertEquals(4, customSuppliers.size());
-        assertTrue(customSuppliers.containsKey(SnapshotsInProgress.TYPE));
-        assertTrue(customSuppliers.containsKey(SnapshotDeletionsInProgress.TYPE));
-        assertTrue(customSuppliers.containsKey(RestoreInProgress.TYPE));
-        assertTrue(customSuppliers.containsKey("foo"));
-
-        {
-            // Eclipse Neon 2 didn't compile the plugins definition inside the lambda expression,
-            // probably due to https://bugs.eclipse.org/bugs/show_bug.cgi?id=511750, which is
-            // fixed in Eclipse Oxygon. Pulled out the plugins definition to make it work in older versions
-            List<ClusterPlugin> plugins = Collections.singletonList(new ClusterPlugin() {
-                @Override
-                public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
-                    return Collections.singletonMap(SnapshotsInProgress.TYPE, () -> null);
-                }
-            });
-            IllegalStateException ise = expectThrows(IllegalStateException.class,
-                    () -> ClusterModule.getClusterStateCustomSuppliers(plugins));
-            assertEquals(ise.getMessage(), "custom supplier key [snapshots] is registered more than once");
-        }
-        {
-            List<ClusterPlugin> plugins = Arrays.asList(new ClusterPlugin() {
-                @Override
-                public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
-                    return Collections.singletonMap("foo", () -> null);
-                }
-            }, new ClusterPlugin() {
-                @Override
-                public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
-                    return Collections.singletonMap("foo", () -> null);
-                }
-            });
-            IllegalStateException ise = expectThrows(IllegalStateException.class,
-                    () -> ClusterModule.getClusterStateCustomSuppliers(plugins));
-            assertEquals(ise.getMessage(), "custom supplier key [foo] is registered more than once");
-        }
-    }
-
     public void testPre63CustomsFiltering() {
         final String whiteListedClusterCustom = randomFrom(ClusterModule.PRE_6_3_CLUSTER_CUSTOMS_WHITE_LIST);
         final String whiteListedMetaDataCustom = randomFrom(ClusterModule.PRE_6_3_METADATA_CUSTOMS_WHITE_LIST);

server/src/test/java/org/elasticsearch/cluster/SimpleClusterStateIT.java

@@ -30,6 +30,7 @@
 import org.elasticsearch.cluster.metadata.MetaData;
 import org.elasticsearch.cluster.routing.RoutingTable;
 import org.elasticsearch.cluster.service.ClusterService;
+import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.UUIDs;
 import org.elasticsearch.common.collect.ImmutableOpenMap;
@@ -38,24 +39,30 @@
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.ByteSizeValue;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.env.Environment;
+import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.index.IndexNotFoundException;
 import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.plugins.ClusterPlugin;
 import org.elasticsearch.plugins.Plugin;
+import org.elasticsearch.script.ScriptService;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.hamcrest.CollectionAssertions;
+import org.elasticsearch.threadpool.ThreadPool;
+import org.elasticsearch.watcher.ResourceWatcherService;
 import org.junit.Before;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.Map;
-import java.util.function.Supplier;
+import java.util.concurrent.atomic.AtomicBoolean;
 
+import static org.elasticsearch.gateway.GatewayService.STATE_NOT_RECOVERED_BLOCK;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertIndexTemplateExists;
 import static org.hamcrest.Matchers.equalTo;
@@ -279,13 +286,11 @@ public void testIndicesIgnoreUnavailableFalse() throws Exception {
         }
     }
 
-    public void testPrivateCustomsAreExcluded() {
+    public void testPrivateCustomsAreExcluded() throws Exception {
+        // ensure that the custom is injected into the cluster state
+        assertBusy(() -> assertTrue(clusterService().state().customs().containsKey("test")));
         ClusterStateResponse clusterStateResponse = client().admin().cluster().prepareState().setCustoms(true).get();
         assertFalse(clusterStateResponse.getState().customs().containsKey("test"));
-        // just to make sure there is something
-        assertTrue(clusterStateResponse.getState().customs().containsKey(SnapshotDeletionsInProgress.TYPE));
-        ClusterState state = internalCluster().getInstance(ClusterService.class).state();
-        assertTrue(state.customs().containsKey("test"));
     }
 
     private static class TestCustom extends AbstractNamedDiffable<ClusterState.Custom> implements ClusterState.Custom {
@@ -333,17 +338,61 @@ public static class PrivateCustomPlugin extends Plugin implements ClusterPlugin
 
         public PrivateCustomPlugin() {}
 
-        @Override
-        public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
-            return Collections.singletonMap("test", () -> new TestCustom(1));
-        }
-
         @Override
         public List<NamedWriteableRegistry.Entry> getNamedWriteables() {
             List<NamedWriteableRegistry.Entry> entries = new ArrayList<>();
             entries.add(new NamedWriteableRegistry.Entry(ClusterState.Custom.class, "test", TestCustom::new));
             entries.add(new NamedWriteableRegistry.Entry(NamedDiff.class, "test", TestCustom::readDiffFrom));
             return entries;
         }
+
+        private final AtomicBoolean installed = new AtomicBoolean();
+
+        @Override
+        public Collection<Object> createComponents(
+            final Client client,
+            final ClusterService clusterService,
+            final ThreadPool threadPool,
+            final ResourceWatcherService resourceWatcherService,
+            final ScriptService scriptService,
+            final NamedXContentRegistry xContentRegistry,
+            final Environment environment,
+            final NodeEnvironment nodeEnvironment,
+            final NamedWriteableRegistry namedWriteableRegistry) {
+            clusterService.addListener(event -> {
+                final ClusterState state = event.state();
+                if (state.getBlocks().hasGlobalBlock(STATE_NOT_RECOVERED_BLOCK)) {
+                    return;
+                }
+
+                if (state.nodes().isLocalNodeElectedMaster()) {
+                    if (state.custom("test") == null) {
+                        if (installed.compareAndSet(false, true)) {
+                            clusterService.submitStateUpdateTask("install-metadata-custom", new ClusterStateUpdateTask(Priority.URGENT) {
+
+                                @Override
+                                public ClusterState execute(ClusterState currentState) {
+                                    if (currentState.custom("test") == null) {
+                                        final ClusterState.Builder builder = ClusterState.builder(currentState);
+                                        builder.putCustom("test", new TestCustom(42));
+                                        return builder.build();
+                                    } else {
+                                        return currentState;
+                                    }
+                                }
+
+                                @Override
+                                public void onFailure(String source, Exception e) {
+                                    throw new AssertionError(e);
+                                }
+
+                            });
+                        }
+                    }
+                }
+
+            });
+            return Collections.emptyList();
+        }
     }
 }

server/src/test/java/org/elasticsearch/cluster/service/ClusterApplierServiceTests.java

@@ -412,7 +412,7 @@ static class TimedClusterApplierService extends ClusterApplierService {
         public volatile Long currentTimeOverride = null;
 
         TimedClusterApplierService(Settings settings, ClusterSettings clusterSettings, ThreadPool threadPool) {
-            super(settings, clusterSettings, threadPool, () -> ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.get(settings)));
+            super(settings, clusterSettings, threadPool);
         }
 
         @Override