api, core, services: make ProtoReflectionService interceptor compatible

core/src/main/java/io/grpc/internal/AbstractServerImplBuilder.java

@@ -29,7 +29,6 @@
 import io.grpc.DecompressorRegistry;
 import io.grpc.HandlerRegistry;
 import io.grpc.InternalChannelz;
-import io.grpc.InternalNotifyOnServerBuild;
 import io.grpc.Server;
 import io.grpc.ServerBuilder;
 import io.grpc.ServerInterceptor;
@@ -77,7 +76,6 @@ public static ServerBuilder<?> forPort(int port) {
       new InternalHandlerRegistry.Builder();
   final List<ServerTransportFilter> transportFilters = new ArrayList<>();
   final List<ServerInterceptor> interceptors = new ArrayList<>();
-  private final List<InternalNotifyOnServerBuild> notifyOnBuildList = new ArrayList<>();
   private final List<ServerStreamTracer.Factory> streamTracerFactories = new ArrayList<>();
   HandlerRegistry fallbackRegistry = DEFAULT_FALLBACK_REGISTRY;
   ObjectPool<? extends Executor> executorPool = DEFAULT_EXECUTOR_POOL;
@@ -114,9 +112,6 @@ public final T addService(ServerServiceDefinition service) {
 
   @Override
   public final T addService(BindableService bindableService) {
-    if (bindableService instanceof InternalNotifyOnServerBuild) {
-      notifyOnBuildList.add((InternalNotifyOnServerBuild) bindableService);
-    }
     return addService(checkNotNull(bindableService, "bindableService").bindService());
   }
 
@@ -222,14 +217,7 @@ protected void setDeadlineTicker(Deadline.Ticker ticker) {
 
   @Override
   public final Server build() {
-    ServerImpl server = new ServerImpl(
-        this,
-        buildTransportServers(getTracerFactories()),
-        Context.ROOT);
-    for (InternalNotifyOnServerBuild notifyTarget : notifyOnBuildList) {
-      notifyTarget.notifyOnBuild(server);
-    }
-    return server;
+    return new ServerImpl(this, buildTransportServers(getTracerFactories()), Context.ROOT);
   }
 
   @VisibleForTesting

core/src/main/java/io/grpc/internal/InternalServerAccessor.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2020 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.internal;
+
+import io.grpc.Context;
+import io.grpc.Internal;
+import io.grpc.Server;
+
+/**
+ * Internal accessor for getting the {@link Server} instance inside server RPC {@link Context}.
+ * This is intended for usage internal to the gRPC team, as it's unclear to us what users would
+ * need. If you *really* think you need to use this, please file an issue for us to discuss a
+ * public API.
+ */
+@Internal
+public class InternalServerAccessor {
+  public static final Context.Key<Server> SERVER_KEY = ServerImpl.SERVER_CONTEXT_KEY;
+
+  // Prevent instantiation.
+  private InternalServerAccessor() {
+  }
+}

core/src/main/java/io/grpc/internal/ServerImpl.java

@@ -45,6 +45,7 @@
 import io.grpc.InternalLogId;
 import io.grpc.InternalServerInterceptors;
 import io.grpc.Metadata;
+import io.grpc.Server;
 import io.grpc.ServerCall;
 import io.grpc.ServerCallHandler;
 import io.grpc.ServerInterceptor;
@@ -91,6 +92,7 @@ public final class ServerImpl extends io.grpc.Server implements InternalInstrume
   private static final Logger log = Logger.getLogger(ServerImpl.class.getName());
   private static final ServerStreamListener NOOP_LISTENER = new NoopListener();
 
+  static final Context.Key<Server> SERVER_CONTEXT_KEY = Context.key("io.grpc.ServerImpl");
   private final InternalLogId logId;
   private final ObjectPool<? extends Executor> executorPool;
   /** Executor for application processing. Safe to read after {@link #start()}. */
@@ -593,7 +595,10 @@ private Context.CancellableContext createContext(
         Metadata headers, StatsTraceContext statsTraceCtx) {
       Long timeoutNanos = headers.get(TIMEOUT_KEY);
 
-      Context baseContext = statsTraceCtx.serverFilterContext(rootContext);
+      Context baseContext =
+          statsTraceCtx
+              .serverFilterContext(rootContext)
+              .withValue(SERVER_CONTEXT_KEY, ServerImpl.this);
 
       if (timeoutNanos == null) {
         return baseContext.withCancellation();

core/src/test/java/io/grpc/internal/ServerImplTest.java

@@ -561,6 +561,7 @@ public ServerCall.Listener<String> startCall(
     Context callContext = callContextReference.get();
     assertNotNull(callContext);
     assertEquals("context added by tracer", SERVER_TRACER_ADDED_KEY.get(callContext));
+    assertEquals(server, ServerImpl.SERVER_CONTEXT_KEY.get(callContext));
 
     streamListener.messagesAvailable(new SingleMessageProducer(STRING_MARSHALLER.stream(request)));
     assertEquals(1, executor.runDueTasks());