Github user vanzin commented on a diff in the pull request:
https://github.com/apache/spark/pull/6457#discussion_r39704642
--- Diff: core/src/main/scala/org/apache/spark/rpc/netty/Dispatcher.scala
---
@@ -0,0 +1,226 @@
+/*
+ * 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.spark.rpc.netty
+
+import java.util.concurrent.{ConcurrentHashMap, LinkedBlockingQueue,
TimeUnit}
+import javax.annotation.concurrent.GuardedBy
+
+import scala.collection.JavaConverters._
+import scala.concurrent.Promise
+import scala.util.control.NonFatal
+
+import org.apache.spark.{SparkException, Logging}
+import org.apache.spark.network.client.RpcResponseCallback
+import org.apache.spark.rpc._
+import org.apache.spark.util.ThreadUtils
+
+private class RpcEndpointPair(val endpoint: RpcEndpoint, val endpointRef:
NettyRpcEndpointRef)
+
+private[netty] class Dispatcher(nettyEnv: NettyRpcEnv) extends Logging {
+
+ private val endpointToInbox = new ConcurrentHashMap[RpcEndpoint, Inbox]()
+
+ // need a name to RpcEndpoint mapping so that we can delivery the
messages
+ private val nameToEndpoint = new ConcurrentHashMap[String,
RpcEndpointPair]()
+
+ private val endpointToEndpointRef = new ConcurrentHashMap[RpcEndpoint,
RpcEndpointRef]()
+
+ // Track the receivers whose inboxes may contain messages.
+ private val receivers = new LinkedBlockingQueue[RpcEndpoint]()
+
+ @GuardedBy("this")
+ private var stopped = false
+
+ def registerRpcEndpoint(name: String, endpoint: RpcEndpoint):
NettyRpcEndpointRef = {
+ val addr = new NettyRpcAddress(nettyEnv.address.host,
nettyEnv.address.port, name)
+ val endpointRef = new NettyRpcEndpointRef(nettyEnv.conf, addr,
nettyEnv)
+ synchronized {
+ if (stopped) {
+ throw new IllegalStateException("RpcEnv has been stopped")
+ }
+ if (nameToEndpoint.putIfAbsent(name, new RpcEndpointPair(endpoint,
endpointRef)) != null) {
+ throw new IllegalArgumentException(s"There is already an
RpcEndpoint called $name")
+ }
+ endpointToEndpointRef.put(endpoint, endpointRef)
+ val inbox = new Inbox(endpointRef, endpoint)
+ endpointToInbox.put(endpoint, inbox)
+ receivers.put(inbox.endpoint)
+ }
+ endpointRef
+ }
+
+ def getRpcEndpointRef(endpoint: RpcEndpoint): RpcEndpointRef =
endpointToEndpointRef.get(endpoint)
+
+ def removeRpcEndpointRef(endpoint: RpcEndpoint): Unit =
endpointToEndpointRef.remove(endpoint)
+
+ def getRpcEndpointRef(name: String): RpcEndpointRef =
nameToEndpoint.get(name).endpointRef
+
+ // Should be idempotent
+ private def unregisterRpcEndpoint(name: String): Unit = {
+ val endpointPair = nameToEndpoint.remove(name)
+ if (endpointPair != null) {
+ val inbox = endpointToInbox.get(endpointPair.endpoint)
+ if (inbox != null) {
+ inbox.stop()
+ receivers.put(inbox.endpoint)
+ }
+ }
+ }
+
+ def stop(rpcEndpointRef: RpcEndpointRef): Unit = {
+ synchronized {
+ if (stopped) {
+ // This endpoint will be stopped by Distpatcher.stop() method.
+ return
+ }
+ unregisterRpcEndpoint(rpcEndpointRef.name)
+ }
+ }
+
+ /**
+ * Send a message to all registered [[RpcEndpoint]]s.
+ * @param message
+ */
+ def broadcastMessage(message: BroadcastMessage): Unit = {
+ val iter = endpointToInbox.values().iterator()
+ while (iter.hasNext) {
+ val inbox = iter.next()
+ postMessageToInbox(inbox, message)
+ }
+ }
+
+ def postMessage(message: RequestMessage, callback: RpcResponseCallback):
Unit = {
+ val receiver = nameToEndpoint.get(message.receiver.name)
+ if (receiver != null) {
+ val inbox = endpointToInbox.get(receiver.endpoint)
+ if (inbox != null) {
+ val rpcCallContext =
+ new RemoteNettyRpcCallContext(
+ nettyEnv, inbox.endpointRef, callback, message.senderAddress,
message.needReply)
+ postMessageToInbox(inbox,
+ ContentMessage(message.senderAddress, message.content,
message.needReply, rpcCallContext))
+ return
+ }
+ }
+ callback.onFailure(
+ new SparkException(s"Could not find ${message.receiver.name} or it
has been stopped"))
+ }
+
+ def postMessage(message: RequestMessage, p: Promise[Any]): Unit = {
+ val receiver = nameToEndpoint.get(message.receiver.name)
+ if (receiver != null) {
+ val inbox = endpointToInbox.get(receiver.endpoint)
+ if (inbox != null) {
+ val rpcCallContext =
+ new LocalNettyRpcCallContext(
+ inbox.endpointRef, message.senderAddress, message.needReply, p)
+ postMessageToInbox(inbox,
+ ContentMessage(message.senderAddress, message.content,
message.needReply, rpcCallContext))
+ return
+ }
+ }
+ p.tryFailure(
+ new SparkException(s"Could not find ${message.receiver.name} or it
has been stopped"))
+ }
+
+ private def postMessageToInbox(inbox: Inbox, message: InboxMessage):
Unit = synchronized {
+ if (stopped) {
+ logWarning(s"Drop ${message} because RpcEnv has been stopped")
+ return
+ }
+ inbox.post(message)
+ receivers.put(inbox.endpoint)
+ }
+
+ private[netty] class MessageLoop extends Runnable {
+ override def run(): Unit = {
+ try {
+ while (true) {
+ try {
+ val endpoint = receivers.take()
+ if (endpoint == DummyEndpoint) {
+ // Put DummyEndpoint back so that other MessageLoops can see
it.
+ receivers.put(DummyEndpoint)
+ return
+ }
+ val inbox = endpointToInbox.get(endpoint)
+ if (inbox != null) {
+ val inboxStopped = inbox.process(Dispatcher.this)
+ if (inboxStopped) {
+ endpointToInbox.remove(endpoint)
+ }
+ } else {
+ // The endpoint has been stopped
+ }
+ } catch {
+ case NonFatal(e) => logError(e.getMessage, e)
+ }
+ }
+ } catch {
+ case ie: InterruptedException => // exit
+ }
+ }
+ }
+
+ private val parallelism =
nettyEnv.conf.getInt("spark.rpc.netty.dispatcher.parallelism",
+ Runtime.getRuntime.availableProcessors())
+
+ private val executor = ThreadUtils.newDaemonFixedThreadPool(parallelism,
"dispatcher-event-loop")
+
+ (0 until parallelism) foreach { _ =>
+ executor.execute(new MessageLoop)
+ }
+
+ def stop(): Unit = {
+ synchronized {
+ if (stopped) {
+ return
+ }
+ stopped = true
+ }
+ // When we reach here, other threads won't update `nameToEndpoint`. So
we can guarantee all
+ // registered endpoints will be stopped correctly.
+ for (name <- nameToEndpoint.keySet().asScala) {
+ unregisterRpcEndpoint(name)
+ }
+ // When we reach here, the new items put into receivers will always be
DummyEndpoint, others
+ // will be rejected. So that we can make sure we will process all
messages that have already in
+ // the Inboxes.
+ receivers.put(DummyEndpoint)
+ executor.shutdown()
+ }
+
+ def awaitTermination(): Unit = {
+ executor.awaitTermination(Long.MaxValue, TimeUnit.MILLISECONDS)
+ }
+
+ /**
+ * Return if the endpoint exists
+ */
+ def verify(name: String): Boolean = {
+ nameToEndpoint.containsKey(name)
+ }
+
+}
+
+/**
+ * A dummy endpoint that indicates MessageLoop should exit its loop.
--- End diff --
This is generally called a "poison", not a "dummy". Also, can this be a
private class inside `Dispatcher` instead?
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