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https://issues.apache.org/jira/browse/FLINK-4362?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15417422#comment-15417422
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ASF GitHub Bot commented on FLINK-4362:
---------------------------------------
Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/2357#discussion_r74443700
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/rpc/akka/AkkaRpcActor.java
---
@@ -0,0 +1,176 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 org.apache.flink.runtime.rpc.akka;
+
+import akka.actor.Status;
+import akka.actor.UntypedActor;
+import akka.pattern.Patterns;
+import org.apache.flink.runtime.rpc.RpcEndpoint;
+import org.apache.flink.runtime.rpc.RpcGateway;
+import org.apache.flink.runtime.rpc.akka.messages.CallAsync;
+import org.apache.flink.runtime.rpc.akka.messages.RpcInvocation;
+import org.apache.flink.runtime.rpc.akka.messages.RunAsync;
+import org.apache.flink.util.Preconditions;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import scala.concurrent.Future;
+
+import java.lang.reflect.Method;
+import java.util.concurrent.Callable;
+
+/**
+ * Akka rpc actor which receives {@link RpcInvocation}, {@link RunAsync}
and {@link CallAsync}
+ * messages.
+ * <p>
+ * The {@link RpcInvocation} designates a rpc and is dispatched to the
given {@link RpcEndpoint}
+ * instance.
+ * <p>
+ * The {@link RunAsync} and {@link CallAsync} messages contain executable
code which is executed
+ * in the context of the actor thread.
+ *
+ * @param <C> Type of the {@link RpcGateway} associated with the {@link
RpcEndpoint}
+ * @param <T> Type of the {@link RpcEndpoint}
+ */
+class AkkaRpcActor<C extends RpcGateway, T extends RpcEndpoint<C>> extends
UntypedActor {
+ private static final Logger LOG =
LoggerFactory.getLogger(AkkaRpcActor.class);
+
+ private final T rpcEndpoint;
+
+ AkkaRpcActor(final T rpcEndpoint) {
+ this.rpcEndpoint = Preconditions.checkNotNull(rpcEndpoint, "rpc
endpoint");
+ }
+
+ @Override
+ public void onReceive(final Object message) {
+ if (message instanceof RunAsync) {
+ handleRunAsync((RunAsync) message);
+ } else if (message instanceof CallAsync) {
+ handleCallAsync((CallAsync) message);
+ } else if (message instanceof RpcInvocation) {
+ handleRpcInvocation((RpcInvocation) message);
+ } else {
+ throw new RuntimeException("Encountered unknown message
type " + message.getClass() +
+ " with value " + message + '.');
+ }
+ }
+
+ /**
+ * Handle rpc invocations by looking up the rpc method on the rpc
endpoint and calling this
+ * method with the provided method arguments. If the method has a
return value, it is returned
+ * to the sender of the call.
+ *
+ * @param rpcInvocation Rpc invocation message
+ */
+ private void handleRpcInvocation(RpcInvocation rpcInvocation) {
+ Method rpcMethod = null;
+
+ try {
+ rpcMethod =
lookupRpcMethod(rpcInvocation.getMethodName(),
rpcInvocation.getParameterTypes());
+ } catch (final NoSuchMethodException e) {
+ LOG.error("Could not find rpc method for rpc
invocation: {}.", rpcInvocation, e);
+ }
+
+ if (rpcMethod != null) {
+ if (rpcMethod.getReturnType().equals(Void.TYPE)) {
+ // No return value to send back
+ try {
+ rpcMethod.invoke(rpcEndpoint,
rpcInvocation.getArgs());
+ } catch (Throwable e) {
+ LOG.error("Error while executing remote
procedure call {}.", rpcMethod, e);
+ }
+ } else {
+ try {
+ Object result =
rpcMethod.invoke(rpcEndpoint, rpcInvocation.getArgs());
+
+ if (result instanceof Future) {
+ // pipe result to sender
+ Patterns.pipe((Future<?>)
result, getContext().dispatcher()).to(getSender());
+ } else {
+ // tell the sender the result
of the computation
+ getSender().tell(new
Status.Success(result), getSelf());
+ }
+ } catch (Throwable e) {
+ // tell the sender about the failure
+ getSender().tell(new Status.Failure(e),
getSelf());
+ }
+ }
+ }
+ }
+
+ /**
+ * Handle asynchronous {@link Callable}. This method simply executes
the given {@link Callable}
+ * in the context of the actor thread.
+ *
+ * @param callAsync Call async message
+ */
+ private void handleCallAsync(CallAsync callAsync) {
+ if (callAsync.getCallable() == null) {
+ final String result = "Received a " +
callAsync.getClass().getName() + " message with an empty " +
--- End diff --
Once we can detect whether a communication is local or remote, we can even
let the call async and run async messages fail on the invocation side if it's a
remote connection.
> Auto generate message sender classes via Java Proxies
> -----------------------------------------------------
>
> Key: FLINK-4362
> URL: https://issues.apache.org/jira/browse/FLINK-4362
> Project: Flink
> Issue Type: Sub-task
> Components: Distributed Coordination
> Reporter: Stephan Ewen
> Assignee: Till Rohrmann
>
> The first version of the RPC service needs to manually create the sender
> classes, which turn method calls into messages.
> This can be automated by using Java Proxies.
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