Enable Serverless API protections dynamically

This commit changes the method for enabling Serverless API protections
(see elastic#93607) from a system property to a runtime property.

Within this project there is no external way to configure this
property - it must be controlled by a plugin - but the RestController
has been changed to dynamically adapt to a change in that property.

server/src/main/java/org/elasticsearch/action/ActionModule.java

@@ -572,7 +572,7 @@ public ActionModule(
             actionPlugins.stream().flatMap(p -> p.indicesAliasesRequestValidators().stream()).toList()
         );
         headersToCopy = headers;
-        restController = new RestController(restInterceptor, nodeClient, circuitBreakerService, usageService, tracer, serverlessEnabled);
+        restController = new RestController(restInterceptor, nodeClient, circuitBreakerService, usageService, tracer);
         reservedClusterStateService = new ReservedClusterStateService(clusterService, reservedStateHandlers);
     }
 

server/src/main/java/org/elasticsearch/rest/RestController.java

@@ -96,15 +96,14 @@ public class RestController implements HttpServerTransport.Dispatcher {
     private final UsageService usageService;
     private final Tracer tracer;
     // If true, the ServerlessScope annotations will be enforced
-    private final boolean serverlessEnabled;
+    private final ServerlessApiProtections apiProtections;
 
     public RestController(
         UnaryOperator<RestHandler> handlerWrapper,
         NodeClient client,
         CircuitBreakerService circuitBreakerService,
         UsageService usageService,
-        Tracer tracer,
-        boolean serverlessEnabled
+        Tracer tracer
     ) {
         this.usageService = usageService;
         this.tracer = tracer;
@@ -115,7 +114,11 @@ public RestController(
         this.client = client;
         this.circuitBreakerService = circuitBreakerService;
         registerHandlerNoWrap(RestRequest.Method.GET, "/favicon.ico", RestApiVersion.current(), new RestFavIconHandler());
-        this.serverlessEnabled = serverlessEnabled;
+        this.apiProtections = new ServerlessApiProtections(false);
+    }
+
+    public ServerlessApiProtections getApiProtections() {
+        return apiProtections;
     }
 
     /**
@@ -374,7 +377,7 @@ private void dispatchRequest(RestRequest request, RestChannel channel, RestHandl
             }
         }
         RestChannel responseChannel = channel;
-        if (serverlessEnabled) {
+        if (apiProtections.isEnabled()) {
             Scope scope = handler.getServerlessScope();
             if (scope == null) {
                 handleServerlessRequestToProtectedResource(request.uri(), request.method(), responseChannel);

server/src/main/java/org/elasticsearch/rest/ServerlessApiProtections.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.rest;
+
+public class ServerlessApiProtections {
+
+    private volatile boolean enabled;
+
+    public ServerlessApiProtections(boolean enabled) {
+        this.enabled = enabled;
+    }
+
+    public boolean isEnabled() {
+        return enabled;
+    }
+
+    public void setEnabled(boolean enabled) {
+        this.enabled = enabled;
+    }
+}

server/src/test/java/org/elasticsearch/rest/RestControllerTests.java

@@ -107,7 +107,7 @@ public void setup() {
         HttpServerTransport httpServerTransport = new TestHttpServerTransport();
         client = new NoOpNodeClient(this.getTestName());
         tracer = mock(Tracer.class);
-        restController = new RestController(null, client, circuitBreakerService, usageService, tracer, false);
+        restController = new RestController(null, client, circuitBreakerService, usageService, tracer);
         restController.registerHandler(
             new Route(GET, "/"),
             (request, channel, client) -> channel.sendResponse(
@@ -129,7 +129,7 @@ public void teardown() throws IOException {
 
     public void testApplyProductSpecificResponseHeaders() {
         final ThreadContext threadContext = client.threadPool().getThreadContext();
-        final RestController restController = new RestController(null, null, circuitBreakerService, usageService, tracer, false);
+        final RestController restController = new RestController(null, null, circuitBreakerService, usageService, tracer);
         RestRequest fakeRequest = new FakeRestRequest.Builder(xContentRegistry()).build();
         AssertingChannel channel = new AssertingChannel(fakeRequest, false, RestStatus.BAD_REQUEST);
         restController.dispatchRequest(fakeRequest, channel, threadContext);
@@ -145,7 +145,7 @@ public void testRequestWithDisallowedMultiValuedHeader() {
         Set<RestHeaderDefinition> headers = new HashSet<>(
             Arrays.asList(new RestHeaderDefinition("header.1", true), new RestHeaderDefinition("header.2", false))
         );
-        final RestController restController = new RestController(null, null, circuitBreakerService, usageService, tracer, false);
+        final RestController restController = new RestController(null, null, circuitBreakerService, usageService, tracer);
         Map<String, List<String>> restHeaders = new HashMap<>();
         restHeaders.put("header.1", Collections.singletonList("boo"));
         restHeaders.put("header.2", List.of("foo", "bar"));
@@ -160,7 +160,7 @@ public void testRequestWithDisallowedMultiValuedHeader() {
      */
     public void testDispatchStartsTrace() {
         final ThreadContext threadContext = client.threadPool().getThreadContext();
-        final RestController restController = new RestController(null, null, circuitBreakerService, usageService, tracer, false);
+        final RestController restController = new RestController(null, null, circuitBreakerService, usageService, tracer);
         RestRequest fakeRequest = new FakeRestRequest.Builder(xContentRegistry()).build();
         final RestController spyRestController = spy(restController);
         when(spyRestController.getAllHandlers(null, fakeRequest.rawPath())).thenReturn(new Iterator<>() {
@@ -189,7 +189,7 @@ public void testRequestWithDisallowedMultiValuedHeaderButSameValues() {
         Set<RestHeaderDefinition> headers = new HashSet<>(
             Arrays.asList(new RestHeaderDefinition("header.1", true), new RestHeaderDefinition("header.2", false))
         );
-        final RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer, false);
+        final RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer);
         Map<String, List<String>> restHeaders = new HashMap<>();
         restHeaders.put("header.1", Collections.singletonList("boo"));
         restHeaders.put("header.2", List.of("foo", "foo"));
@@ -260,7 +260,7 @@ public void testRegisterAsReplacedHandler() {
     }
 
     public void testRegisterSecondMethodWithDifferentNamedWildcard() {
-        final RestController restController = new RestController(null, null, circuitBreakerService, usageService, tracer, false);
+        final RestController restController = new RestController(null, null, circuitBreakerService, usageService, tracer);
 
         RestRequest.Method firstMethod = randomFrom(methodList);
         RestRequest.Method secondMethod = randomFrom(methodList.stream().filter(m -> m != firstMethod).toList());
@@ -287,7 +287,7 @@ public void testRestHandlerWrapper() throws Exception {
         final RestController restController = new RestController(h -> {
             assertSame(handler, h);
             return (RestRequest request, RestChannel channel, NodeClient client) -> wrapperCalled.set(true);
-        }, client, circuitBreakerService, usageService, tracer, false);
+        }, client, circuitBreakerService, usageService, tracer);
         restController.registerHandler(new Route(GET, "/wrapped"), handler);
         RestRequest request = testRestRequest("/wrapped", "{}", XContentType.JSON);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.BAD_REQUEST);
@@ -374,7 +374,7 @@ public void testDispatchRequiresContentTypeForRequestsWithContent() {
         String content = randomAlphaOfLength((int) Math.round(BREAKER_LIMIT.getBytes() / inFlightRequestsBreaker.getOverhead()));
         RestRequest request = testRestRequest("/", content, null);
         AssertingChannel channel = new AssertingChannel(request, true, RestStatus.NOT_ACCEPTABLE);
-        restController = new RestController(null, null, circuitBreakerService, usageService, tracer, false);
+        restController = new RestController(null, null, circuitBreakerService, usageService, tracer);
         restController.registerHandler(
             new Route(GET, "/"),
             (r, c, client) -> c.sendResponse(new RestResponse(RestStatus.OK, RestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY))
@@ -761,7 +761,7 @@ public Method method() {
 
     public void testDispatchCompatibleHandler() {
 
-        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer, false);
+        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer);
 
         final RestApiVersion version = RestApiVersion.minimumSupported();
 
@@ -785,7 +785,7 @@ public void testDispatchCompatibleHandler() {
 
     public void testDispatchCompatibleRequestToNewlyAddedHandler() {
 
-        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer, false);
+        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer);
 
         final RestApiVersion version = RestApiVersion.minimumSupported();
 
@@ -820,7 +820,7 @@ private FakeRestRequest requestWithContent(String mediaType) {
     }
 
     public void testCurrentVersionVNDMediaTypeIsNotUsingCompatibility() {
-        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer, false);
+        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer);
 
         final RestApiVersion version = RestApiVersion.current();
 
@@ -845,7 +845,7 @@ public void testCurrentVersionVNDMediaTypeIsNotUsingCompatibility() {
     }
 
     public void testCustomMediaTypeValidation() {
-        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer, false);
+        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer);
 
         final String mediaType = "application/x-protobuf";
         FakeRestRequest fakeRestRequest = requestWithContent(mediaType);
@@ -871,7 +871,7 @@ public void handleRequest(RestRequest request, RestChannel channel, NodeClient c
     }
 
     public void testBrowserSafelistedContentTypesAreRejected() {
-        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer, false);
+        RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer);
 
         final String mediaType = randomFrom(RestController.SAFELISTED_MEDIA_TYPES);
         FakeRestRequest fakeRestRequest = requestWithContent(mediaType);
@@ -892,7 +892,7 @@ public void handleRequest(RestRequest request, RestChannel channel, NodeClient c
     }
 
     public void testRegisterWithReservedPath() {
-        final RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer, false);
+        final RestController restController = new RestController(null, client, circuitBreakerService, usageService, tracer);
         for (String path : RestController.RESERVED_PATHS) {
             IllegalArgumentException iae = expectThrows(IllegalArgumentException.class, () -> {
                 restController.registerHandler(
@@ -910,7 +910,7 @@ public void testRegisterWithReservedPath() {
      * Test that when serverless is disabled, all endpoints are available regardless of ServerlessScope annotations.
      */
     public void testApiProtectionWithServerlessDisabled() {
-        final RestController restController = new RestController(null, client, circuitBreakerService, new UsageService(), tracer, false);
+        final RestController restController = new RestController(null, client, circuitBreakerService, new UsageService(), tracer);
         restController.registerHandler(new PublicRestHandler());
         restController.registerHandler(new InternalRestHandler());
         restController.registerHandler(new HiddenRestHandler());
@@ -926,7 +926,7 @@ public void testApiProtectionWithServerlessDisabled() {
      * Test that when serverless is enabled, a normal user can not access endpoints without a ServerlessScope annotation.
      */
     public void testApiProtectionWithServerlessEnabledAsEndUser() {
-        final RestController restController = new RestController(null, client, circuitBreakerService, new UsageService(), tracer, true);
+        final RestController restController = new RestController(null, client, circuitBreakerService, new UsageService(), tracer);
         restController.registerHandler(new PublicRestHandler());
         restController.registerHandler(new InternalRestHandler());
         restController.registerHandler(new HiddenRestHandler());

server/src/test/java/org/elasticsearch/rest/RestHttpResponseHeadersTests.java

@@ -78,7 +78,7 @@ public void testUnsupportedMethodResponseHttpHeader() throws Exception {
         );
 
         UsageService usageService = new UsageService();
-        RestController restController = new RestController(null, null, circuitBreakerService, usageService, Tracer.NOOP, false);
+        RestController restController = new RestController(null, null, circuitBreakerService, usageService, Tracer.NOOP);
 
         // A basic RestHandler handles requests to the endpoint
         RestHandler restHandler = (request, channel, client) -> channel.sendResponse(new RestResponse(RestStatus.OK, ""));

server/src/test/java/org/elasticsearch/rest/action/admin/indices/RestValidateQueryActionTests.java

@@ -54,7 +54,7 @@ public class RestValidateQueryActionTests extends AbstractSearchTestCase {
     private NodeClient client = new NodeClient(Settings.EMPTY, threadPool);
 
     private UsageService usageService = new UsageService();
-    private RestController controller = new RestController(null, client, new NoneCircuitBreakerService(), usageService, Tracer.NOOP, false);
+    private RestController controller = new RestController(null, client, new NoneCircuitBreakerService(), usageService, Tracer.NOOP);
     private RestValidateQueryAction action = new RestValidateQueryAction();
 
     /**

test/framework/src/main/java/org/elasticsearch/test/rest/RestActionTestCase.java

@@ -40,7 +40,7 @@ public abstract class RestActionTestCase extends ESTestCase {
     @Before
     public void setUpController() {
         verifyingClient = new VerifyingClient(this.getTestName());
-        controller = new RestController(null, verifyingClient, new NoneCircuitBreakerService(), new UsageService(), Tracer.NOOP, false);
+        controller = new RestController(null, verifyingClient, new NoneCircuitBreakerService(), new UsageService(), Tracer.NOOP);
     }
 
     @After

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/termsenum/action/RestTermsEnumActionTests.java

@@ -57,8 +57,7 @@ public class RestTermsEnumActionTests extends ESTestCase {
         client,
         new NoneCircuitBreakerService(),
         usageService,
-        Tracer.NOOP,
-        false
+        Tracer.NOOP
     );
     private static RestTermsEnumAction action = new RestTermsEnumAction();