Github user zsxwing commented on a diff in the pull request:
https://github.com/apache/spark/pull/4588#discussion_r27005722
--- Diff: core/src/main/scala/org/apache/spark/rpc/RpcEnv.scala ---
@@ -0,0 +1,412 @@
+/*
+ * 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
+
+import java.net.URI
+
+import scala.concurrent.{Await, Future}
+import scala.concurrent.duration._
+import scala.language.postfixOps
+import scala.reflect.ClassTag
+
+import org.apache.spark.{Logging, SparkException, SecurityManager,
SparkConf}
+import org.apache.spark.util.{AkkaUtils, Utils}
+
+/**
+ * An RPC environment. [[RpcEndpoint]]s need to register itself with a
name to [[RpcEnv]] to
+ * receives messages. Then [[RpcEnv]] will process messages sent from
[[RpcEndpointRef]] or remote
+ * nodes, and deliver them to corresponding [[RpcEndpoint]]s.
+ *
+ * [[RpcEnv]] also provides some methods to retrieve [[RpcEndpointRef]]s
given name or uri.
+ */
+private[spark] abstract class RpcEnv(conf: SparkConf) {
+
+ private[spark] val defaultLookupTimeout = AkkaUtils.lookupTimeout(conf)
+
+ /**
+ * Return RpcEndpointRef of the registered [[RpcEndpoint]]. Will be used
to implement
+ * [[RpcEndpoint.self]].
+ */
+ private[rpc] def endpointRef(endpoint: RpcEndpoint): RpcEndpointRef
+
+ /**
+ * Return the address that [[RpcEnv]] is listening to.
+ */
+ def address: RpcAddress
+
+ /**
+ * Register a [[RpcEndpoint]] with a name and return its
[[RpcEndpointRef]]. [[RpcEnv]] does not
+ * guarantee thread-safety.
+ */
+ def setupEndpoint(name: String, endpoint: RpcEndpoint): RpcEndpointRef
+
+ /**
+ * Register a [[RpcEndpoint]] with a name and return its
[[RpcEndpointRef]]. [[RpcEnv]] should
+ * make sure thread-safely sending messages to [[RpcEndpoint]].
+ *
+ * Thread-safety means processing of one message happens before
processing of the next message by
+ * the same [[RpcEndpoint]]. In the other words, changes to internal
fields of a [[RpcEndpoint]]
+ * are visible when processing the next message, and fields in the
[[RpcEndpoint]] need not be
+ * volatile or equivalent.
+ *
+ * However, there is no guarantee that the same thread will be executing
the same [[RpcEndpoint]]
+ * for different messages.
+ */
+ def setupThreadSafeEndpoint(name: String, endpoint: RpcEndpoint):
RpcEndpointRef
+
+ /**
+ * Retrieve the [[RpcEndpointRef]] represented by `url` asynchronously.
+ */
+ def asyncSetupEndpointRefByUrl(url: String): Future[RpcEndpointRef]
+
+ /**
+ * Retrieve the [[RpcEndpointRef]] represented by `url`. This is a
blocking action.
+ */
+ def setupEndpointRefByUrl(url: String): RpcEndpointRef = {
+ Await.result(asyncSetupEndpointRefByUrl(url), defaultLookupTimeout)
+ }
+
+ /**
+ * Retrieve the [[RpcEndpointRef]] represented by `systemName`,
`address` and `endpointName`
+ * asynchronously.
+ */
+ def asyncSetupEndpointRef(
+ systemName: String, address: RpcAddress, endpointName: String):
Future[RpcEndpointRef] = {
+ asyncSetupEndpointRefByUrl(uriOf(systemName, address, endpointName))
+ }
+
+ /**
+ * Retrieve the [[RpcEndpointRef]] represented by `systemName`,
`address` and `endpointName`.
+ * This is a blocking action.
+ */
+ def setupEndpointRef(
+ systemName: String, address: RpcAddress, endpointName: String):
RpcEndpointRef = {
+ setupEndpointRefByUrl(uriOf(systemName, address, endpointName))
+ }
+
+ /**
+ * Stop [[RpcEndpoint]] specified by `endpoint`.
+ */
+ def stop(endpoint: RpcEndpointRef): Unit
+
+ /**
+ * Shutdown this [[RpcEnv]] asynchronously. If need to make sure
[[RpcEnv]] exits successfully,
+ * call [[awaitTermination()]] straight after [[shutdown()]].
+ */
+ def shutdown(): Unit
+
+ /**
+ * Wait until [[RpcEnv]] exits.
+ *
+ * TODO do we need a timeout parameter?
+ */
+ def awaitTermination(): Unit
+
+ /**
+ * Create a URI used to create a [[RpcEndpointRef]]. Use this one to
create the URI instead of
+ * creating it manually because different [[RpcEnv]] may have different
formats.
+ */
+ def uriOf(systemName: String, address: RpcAddress, endpointName:
String): String
+}
+
+private[spark] case class RpcEnvConfig(
+ conf: SparkConf,
+ name: String,
+ host: String,
+ port: Int,
+ securityManager: SecurityManager)
+
+/**
+ * A RpcEnv implementation must have a [[RpcEnvFactory]] implementation
with an empty constructor
+ * so that it can be created via Reflection.
+ */
+private[spark] object RpcEnv {
+
+ private def getRpcEnvFactory(conf: SparkConf): RpcEnvFactory = {
+ // Add more RpcEnv implementations here
+ val rpcEnvNames = Map("akka" ->
"org.apache.spark.rpc.akka.AkkaRpcEnvFactory")
+ val rpcEnvName = conf.get("spark.rpc", "akka")
+ val rpcEnvFactoryClassName =
rpcEnvNames.getOrElse(rpcEnvName.toLowerCase, rpcEnvName)
+ Class.forName(rpcEnvFactoryClassName, true,
Utils.getContextOrSparkClassLoader).
+ newInstance().asInstanceOf[RpcEnvFactory]
+ }
+
+ def create(
+ name: String,
+ host: String,
+ port: Int,
+ conf: SparkConf,
+ securityManager: SecurityManager): RpcEnv = {
+ // Using Reflection to create the RpcEnv to avoid to depend on Akka
directly
+ val config = RpcEnvConfig(conf, name, host, port, securityManager)
+ getRpcEnvFactory(conf).create(config)
+ }
+
+}
+
+/**
+ * A factory class to create the [[RpcEnv]]. It must have an empty
constructor so that it can be
+ * created using Reflection.
+ */
+private[spark] trait RpcEnvFactory {
+
+ def create(config: RpcEnvConfig): RpcEnv
+}
+
+/**
+ * An end point for the RPC that defines what functions to trigger given a
message.
+ *
+ * It is guaranteed that `onStart`, `receive` and `onStop` will be called
in sequence.
+ *
+ * The lift-cycle will be:
+ *
+ * constructor onStart receive* onStop
+ *
+ * Note: `receive` can be called concurrently. If you want `receive` is
thread-safe, please use
+ * [[RpcEnv.setupThreadSafeEndpoint]]
+ *
+ * If any error is thrown from one of [[RpcEndpoint]] methods except
`onError`, `onError` will be
+ * invoked with the cause. If `onError` throws an error, [[RpcEnv]] will
ignore it.
+ */
+private[spark] trait RpcEndpoint {
+
+ /**
+ * The [[RpcEnv]] that this [[RpcEndpoint]] is registered to.
+ */
+ val rpcEnv: RpcEnv
+
+ /**
+ * The [[RpcEndpointRef]] of this [[RpcEndpoint]]. `self` will become
valid when `onStart` is
+ * called.
+ *
+ * Note: Because before `onStart`, [[RpcEndpoint]] has not yet been
registered and there is not
+ * valid [[RpcEndpointRef]] for it. So don't call `self` before
`onStart` is called.
+ */
+ final def self: RpcEndpointRef = {
+ require(rpcEnv != null, "rpcEnv has not been initialized")
+ rpcEnv.endpointRef(this)
+ }
+
+ /**
+ * Process messages from [[RpcEndpointRef.send]] or
[[RpcCallContext.reply)]]
+ */
+ def receive: PartialFunction[Any, Unit] = {
+ case _ => throw new SparkException(self + " does not implement
'receive'")
+ }
+
+ /**
+ * Process messages from [[RpcEndpointRef.sendWithReply]]
+ */
+ def receiveAndReply(context: RpcCallContext): PartialFunction[Any, Unit]
= {
+ case _ => context.sendFailure(new SparkException(self + " won't reply
anything"))
+ }
+
+ /**
+ * Call onError when any exception is thrown during handling messages.
+ *
+ * @param cause
+ */
+ def onError(cause: Throwable): Unit = {
+ // By default, throw e and let RpcEnv handle it
+ throw cause
+ }
+
+ /**
+ * Invoked before [[RpcEndpoint]] starts to handle any message.
+ */
+ def onStart(): Unit = {
+ // By default, do nothing.
+ }
+
+ /**
+ * Invoked when [[RpcEndpoint]] is stopping.
+ */
+ def onStop(): Unit = {
+ // By default, do nothing.
+ }
+
+ /**
+ * Invoked when `remoteAddress` is connected to the current node.
+ */
+ def onConnected(remoteAddress: RpcAddress): Unit = {
+ // By default, do nothing.
+ }
+
+ /**
+ * Invoked when `remoteAddress` is lost.
+ */
+ def onDisconnected(remoteAddress: RpcAddress): Unit = {
+ // By default, do nothing.
+ }
+
+ /**
+ * Invoked when some network error happens in the connection between the
current node and
+ * `remoteAddress`.
+ */
+ def onNetworkError(cause: Throwable, remoteAddress: RpcAddress): Unit = {
+ // By default, do nothing.
+ }
+
+ /**
+ * A convenient method to stop [[RpcEndpoint]].
+ */
+ final def stop(): Unit = {
+ val _self = self
+ if (_self != null) {
+ rpcEnv.stop(self)
+ }
+ }
+}
+
+/**
+ * A reference for a remote [[RpcEndpoint]]. [[RpcEndpointRef]] is
thread-safe.
+ */
+private[spark] abstract class RpcEndpointRef(@transient conf: SparkConf)
+ extends Serializable with Logging {
+
+ private[this] val maxRetries = conf.getInt("spark.akka.num.retries", 3)
+ private[this] val retryWaitMs = conf.getLong("spark.akka.retry.wait",
3000)
+ private[this] val defaultTimeout =
conf.getLong("spark.akka.lookupTimeout", 30) seconds
+
+ /**
+ * return the address for the [[RpcEndpointRef]]
+ */
+ def address: RpcAddress
+
+ def name: String
+
+ /**
+ * Send a message to the corresponding [[RpcEndpoint]] and get its
result within a default
+ * timeout, or throw a SparkException if this fails even after the
default number of retries.
+ *
+ * Note: this is a blocking action which may cost a lot of time, so
don't call it in an message
+ * loop of [[RpcEndpoint]].
+ *
+ * @param message the message to send
+ * @tparam T type of the reply message
+ * @return the reply message from the corresponding [[RpcEndpoint]]
+ */
+ def askWithReply[T: ClassTag](message: Any): T = askWithReply(message,
defaultTimeout)
+
+ /**
+ * Send a message to the corresponding [[RpcEndpoint.receive]] and get
its result within a
+ * specified timeout, throw a SparkException if this fails even after
the specified number of
+ * retries.
+ *
+ * Note: this is a blocking action which may cost a lot of time, so
don't call it in an message
+ * loop of [[RpcEndpoint]].
+ *
+ * @param message the message to send
+ * @param timeout the timeout duration
+ * @tparam T type of the reply message
+ * @return the reply message from the corresponding [[RpcEndpoint]]
+ */
+ def askWithReply[T: ClassTag](message: Any, timeout: FiniteDuration): T
= {
--- End diff --
Updated the docs.
---
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