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Diffstat (limited to 'core/src/main/scala/org/apache/spark/deploy/rest/RestSubmissionServer.scala')
-rw-r--r-- | core/src/main/scala/org/apache/spark/deploy/rest/RestSubmissionServer.scala | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/core/src/main/scala/org/apache/spark/deploy/rest/RestSubmissionServer.scala b/core/src/main/scala/org/apache/spark/deploy/rest/RestSubmissionServer.scala new file mode 100644 index 0000000000..2e78d03e5c --- /dev/null +++ b/core/src/main/scala/org/apache/spark/deploy/rest/RestSubmissionServer.scala @@ -0,0 +1,318 @@ +/* + * 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.deploy.rest + +import java.net.InetSocketAddress +import javax.servlet.http.{HttpServlet, HttpServletRequest, HttpServletResponse} + +import scala.io.Source +import com.fasterxml.jackson.core.JsonProcessingException +import org.eclipse.jetty.server.Server +import org.eclipse.jetty.servlet.{ServletHolder, ServletContextHandler} +import org.eclipse.jetty.util.thread.QueuedThreadPool +import org.json4s._ +import org.json4s.jackson.JsonMethods._ + +import org.apache.spark.{Logging, SparkConf, SPARK_VERSION => sparkVersion} +import org.apache.spark.util.Utils + +/** + * A server that responds to requests submitted by the [[RestSubmissionClient]]. + * + * This server responds with different HTTP codes depending on the situation: + * 200 OK - Request was processed successfully + * 400 BAD REQUEST - Request was malformed, not successfully validated, or of unexpected type + * 468 UNKNOWN PROTOCOL VERSION - Request specified a protocol this server does not understand + * 500 INTERNAL SERVER ERROR - Server throws an exception internally while processing the request + * + * The server always includes a JSON representation of the relevant [[SubmitRestProtocolResponse]] + * in the HTTP body. If an error occurs, however, the server will include an [[ErrorResponse]] + * instead of the one expected by the client. If the construction of this error response itself + * fails, the response will consist of an empty body with a response code that indicates internal + * server error. + */ +private[spark] abstract class RestSubmissionServer( + val host: String, + val requestedPort: Int, + val masterConf: SparkConf) extends Logging { + protected val submitRequestServlet: SubmitRequestServlet + protected val killRequestServlet: KillRequestServlet + protected val statusRequestServlet: StatusRequestServlet + + private var _server: Option[Server] = None + + // A mapping from URL prefixes to servlets that serve them. Exposed for testing. + protected val baseContext = s"/${RestSubmissionServer.PROTOCOL_VERSION}/submissions" + protected lazy val contextToServlet = Map[String, RestServlet]( + s"$baseContext/create/*" -> submitRequestServlet, + s"$baseContext/kill/*" -> killRequestServlet, + s"$baseContext/status/*" -> statusRequestServlet, + "/*" -> new ErrorServlet // default handler + ) + + /** Start the server and return the bound port. */ + def start(): Int = { + val (server, boundPort) = Utils.startServiceOnPort[Server](requestedPort, doStart, masterConf) + _server = Some(server) + logInfo(s"Started REST server for submitting applications on port $boundPort") + boundPort + } + + /** + * Map the servlets to their corresponding contexts and attach them to a server. + * Return a 2-tuple of the started server and the bound port. + */ + private def doStart(startPort: Int): (Server, Int) = { + val server = new Server(new InetSocketAddress(host, startPort)) + val threadPool = new QueuedThreadPool + threadPool.setDaemon(true) + server.setThreadPool(threadPool) + val mainHandler = new ServletContextHandler + mainHandler.setContextPath("/") + contextToServlet.foreach { case (prefix, servlet) => + mainHandler.addServlet(new ServletHolder(servlet), prefix) + } + server.setHandler(mainHandler) + server.start() + val boundPort = server.getConnectors()(0).getLocalPort + (server, boundPort) + } + + def stop(): Unit = { + _server.foreach(_.stop()) + } +} + +private[rest] object RestSubmissionServer { + val PROTOCOL_VERSION = RestSubmissionClient.PROTOCOL_VERSION + val SC_UNKNOWN_PROTOCOL_VERSION = 468 +} + +/** + * An abstract servlet for handling requests passed to the [[RestSubmissionServer]]. + */ +private[rest] abstract class RestServlet extends HttpServlet with Logging { + + /** + * Serialize the given response message to JSON and send it through the response servlet. + * This validates the response before sending it to ensure it is properly constructed. + */ + protected def sendResponse( + responseMessage: SubmitRestProtocolResponse, + responseServlet: HttpServletResponse): Unit = { + val message = validateResponse(responseMessage, responseServlet) + responseServlet.setContentType("application/json") + responseServlet.setCharacterEncoding("utf-8") + responseServlet.getWriter.write(message.toJson) + } + + /** + * Return any fields in the client request message that the server does not know about. + * + * The mechanism for this is to reconstruct the JSON on the server side and compare the + * diff between this JSON and the one generated on the client side. Any fields that are + * only in the client JSON are treated as unexpected. + */ + protected def findUnknownFields( + requestJson: String, + requestMessage: SubmitRestProtocolMessage): Array[String] = { + val clientSideJson = parse(requestJson) + val serverSideJson = parse(requestMessage.toJson) + val Diff(_, _, unknown) = clientSideJson.diff(serverSideJson) + unknown match { + case j: JObject => j.obj.map { case (k, _) => k }.toArray + case _ => Array.empty[String] // No difference + } + } + + /** Return a human readable String representation of the exception. */ + protected def formatException(e: Throwable): String = { + val stackTraceString = e.getStackTrace.map { "\t" + _ }.mkString("\n") + s"$e\n$stackTraceString" + } + + /** Construct an error message to signal the fact that an exception has been thrown. */ + protected def handleError(message: String): ErrorResponse = { + val e = new ErrorResponse + e.serverSparkVersion = sparkVersion + e.message = message + e + } + + /** + * Parse a submission ID from the relative path, assuming it is the first part of the path. + * For instance, we expect the path to take the form /[submission ID]/maybe/something/else. + * The returned submission ID cannot be empty. If the path is unexpected, return None. + */ + protected def parseSubmissionId(path: String): Option[String] = { + if (path == null || path.isEmpty) { + None + } else { + path.stripPrefix("/").split("/").headOption.filter(_.nonEmpty) + } + } + + /** + * Validate the response to ensure that it is correctly constructed. + * + * If it is, simply return the message as is. Otherwise, return an error response instead + * to propagate the exception back to the client and set the appropriate error code. + */ + private def validateResponse( + responseMessage: SubmitRestProtocolResponse, + responseServlet: HttpServletResponse): SubmitRestProtocolResponse = { + try { + responseMessage.validate() + responseMessage + } catch { + case e: Exception => + responseServlet.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR) + handleError("Internal server error: " + formatException(e)) + } + } +} + +/** + * A servlet for handling kill requests passed to the [[RestSubmissionServer]]. + */ +private[rest] abstract class KillRequestServlet extends RestServlet { + + /** + * If a submission ID is specified in the URL, have the Master kill the corresponding + * driver and return an appropriate response to the client. Otherwise, return error. + */ + protected override def doPost( + request: HttpServletRequest, + response: HttpServletResponse): Unit = { + val submissionId = parseSubmissionId(request.getPathInfo) + val responseMessage = submissionId.map(handleKill).getOrElse { + response.setStatus(HttpServletResponse.SC_BAD_REQUEST) + handleError("Submission ID is missing in kill request.") + } + sendResponse(responseMessage, response) + } + + protected def handleKill(submissionId: String): KillSubmissionResponse +} + +/** + * A servlet for handling status requests passed to the [[RestSubmissionServer]]. + */ +private[rest] abstract class StatusRequestServlet extends RestServlet { + + /** + * If a submission ID is specified in the URL, request the status of the corresponding + * driver from the Master and include it in the response. Otherwise, return error. + */ + protected override def doGet( + request: HttpServletRequest, + response: HttpServletResponse): Unit = { + val submissionId = parseSubmissionId(request.getPathInfo) + val responseMessage = submissionId.map(handleStatus).getOrElse { + response.setStatus(HttpServletResponse.SC_BAD_REQUEST) + handleError("Submission ID is missing in status request.") + } + sendResponse(responseMessage, response) + } + + protected def handleStatus(submissionId: String): SubmissionStatusResponse +} + +/** + * A servlet for handling submit requests passed to the [[RestSubmissionServer]]. + */ +private[rest] abstract class SubmitRequestServlet extends RestServlet { + + /** + * Submit an application to the Master with parameters specified in the request. + * + * The request is assumed to be a [[SubmitRestProtocolRequest]] in the form of JSON. + * If the request is successfully processed, return an appropriate response to the + * client indicating so. Otherwise, return error instead. + */ + protected override def doPost( + requestServlet: HttpServletRequest, + responseServlet: HttpServletResponse): Unit = { + val responseMessage = + try { + val requestMessageJson = Source.fromInputStream(requestServlet.getInputStream).mkString + val requestMessage = SubmitRestProtocolMessage.fromJson(requestMessageJson) + // The response should have already been validated on the client. + // In case this is not true, validate it ourselves to avoid potential NPEs. + requestMessage.validate() + handleSubmit(requestMessageJson, requestMessage, responseServlet) + } catch { + // The client failed to provide a valid JSON, so this is not our fault + case e @ (_: JsonProcessingException | _: SubmitRestProtocolException) => + responseServlet.setStatus(HttpServletResponse.SC_BAD_REQUEST) + handleError("Malformed request: " + formatException(e)) + } + sendResponse(responseMessage, responseServlet) + } + + protected def handleSubmit( + requestMessageJson: String, + requestMessage: SubmitRestProtocolMessage, + responseServlet: HttpServletResponse): SubmitRestProtocolResponse +} + +/** + * A default servlet that handles error cases that are not captured by other servlets. + */ +private class ErrorServlet extends RestServlet { + private val serverVersion = RestSubmissionServer.PROTOCOL_VERSION + + /** Service a faulty request by returning an appropriate error message to the client. */ + protected override def service( + request: HttpServletRequest, + response: HttpServletResponse): Unit = { + val path = request.getPathInfo + val parts = path.stripPrefix("/").split("/").filter(_.nonEmpty).toList + var versionMismatch = false + var msg = + parts match { + case Nil => + // http://host:port/ + "Missing protocol version." + case `serverVersion` :: Nil => + // http://host:port/correct-version + "Missing the /submissions prefix." + case `serverVersion` :: "submissions" :: tail => + // http://host:port/correct-version/submissions/* + "Missing an action: please specify one of /create, /kill, or /status." + case unknownVersion :: tail => + // http://host:port/unknown-version/* + versionMismatch = true + s"Unknown protocol version '$unknownVersion'." + case _ => + // never reached + s"Malformed path $path." + } + msg += s" Please submit requests through http://[host]:[port]/$serverVersion/submissions/..." + val error = handleError(msg) + // If there is a version mismatch, include the highest protocol version that + // this server supports in case the client wants to retry with our version + if (versionMismatch) { + error.highestProtocolVersion = serverVersion + response.setStatus(RestSubmissionServer.SC_UNKNOWN_PROTOCOL_VERSION) + } else { + response.setStatus(HttpServletResponse.SC_BAD_REQUEST) + } + sendResponse(error, response) + } +} |