序

本文主要研究一下flink的log.file配置

log4j.properties

flink-release-1.6.2/flink-dist/src/main/flink-bin/conf/log4j.properties

# This affects logging for both user code and Flink
log4j.rootLogger=INFO, file

# Uncomment this if you want to _only_ change Flink's logging
#log4j.logger.org.apache.flink=INFO

# The following lines keep the log level of common libraries/connectors on
# log level INFO. The root logger does not override this. You have to manually
# change the log levels here.
log4j.logger.akka=INFO
log4j.logger.org.apache.kafka=INFO
log4j.logger.org.apache.hadoop=INFO
log4j.logger.org.apache.zookeeper=INFO

# Log all infos in the given file
log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.file=${log.file}
log4j.appender.file.append=false
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss,SSS} %-5p %-60c %x - %m%n

# Suppress the irrelevant (wrong) warnings from the Netty channel handler
log4j.logger.org.apache.flink.shaded.akka.org.jboss.netty.channel.DefaultChannelPipeline=ERROR, file

• 这里使用log.file这个系统属性配置log4j.appender.file.file

MiniCluster

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/minicluster/MiniCluster.java

	/**
	 * Starts the mini cluster, based on the configured properties.
	 *
	 * @throws Exception This method passes on any exception that occurs during the startup of
	 *                   the mini cluster.
	 */
	public void start() throws Exception {
		synchronized (lock) {
			checkState(!running, "FlinkMiniCluster is already running");

			LOG.info("Starting Flink Mini Cluster");
			LOG.debug("Using configuration {}", miniClusterConfiguration);

			final Configuration configuration = miniClusterConfiguration.getConfiguration();
			final Time rpcTimeout = miniClusterConfiguration.getRpcTimeout();
			final int numTaskManagers = miniClusterConfiguration.getNumTaskManagers();
			final boolean useSingleRpcService = miniClusterConfiguration.getRpcServiceSharing() == RpcServiceSharing.SHARED;

			try {
				initializeIOFormatClasses(configuration);

				LOG.info("Starting Metrics Registry");
				metricRegistry = createMetricRegistry(configuration);
				this.jobManagerMetricGroup = MetricUtils.instantiateJobManagerMetricGroup(
					metricRegistry,
					"localhost");

				final RpcService jobManagerRpcService;
				final RpcService resourceManagerRpcService;
				final RpcService[] taskManagerRpcServices = new RpcService[numTaskManagers];

				// bring up all the RPC services
				LOG.info("Starting RPC Service(s)");

				// we always need the 'commonRpcService' for auxiliary calls
				commonRpcService = createRpcService(configuration, rpcTimeout, false, null);

				// TODO: Temporary hack until the metric query service is ported to the RpcEndpoint
				final ActorSystem actorSystem = ((AkkaRpcService) commonRpcService).getActorSystem();
				metricRegistry.startQueryService(actorSystem, null);

				if (useSingleRpcService) {
					for (int i = 0; i < numTaskManagers; i++) {
						taskManagerRpcServices[i] = commonRpcService;
					}

					jobManagerRpcService = commonRpcService;
					resourceManagerRpcService = commonRpcService;

					this.resourceManagerRpcService = null;
					this.jobManagerRpcService = null;
					this.taskManagerRpcServices = null;
				}
				else {
					// start a new service per component, possibly with custom bind addresses
					final String jobManagerBindAddress = miniClusterConfiguration.getJobManagerBindAddress();
					final String taskManagerBindAddress = miniClusterConfiguration.getTaskManagerBindAddress();
					final String resourceManagerBindAddress = miniClusterConfiguration.getResourceManagerBindAddress();

					jobManagerRpcService = createRpcService(configuration, rpcTimeout, true, jobManagerBindAddress);
					resourceManagerRpcService = createRpcService(configuration, rpcTimeout, true, resourceManagerBindAddress);

					for (int i = 0; i < numTaskManagers; i++) {
						taskManagerRpcServices[i] = createRpcService(
								configuration, rpcTimeout, true, taskManagerBindAddress);
					}

					this.jobManagerRpcService = jobManagerRpcService;
					this.taskManagerRpcServices = taskManagerRpcServices;
					this.resourceManagerRpcService = resourceManagerRpcService;
				}

				// create the high-availability services
				LOG.info("Starting high-availability services");
				haServices = HighAvailabilityServicesUtils.createAvailableOrEmbeddedServices(
					configuration,
					commonRpcService.getExecutor());

				blobServer = new BlobServer(configuration, haServices.createBlobStore());
				blobServer.start();

				heartbeatServices = HeartbeatServices.fromConfiguration(configuration);

				// bring up the ResourceManager(s)
				LOG.info("Starting ResourceManger");
				resourceManagerRunner = startResourceManager(
					configuration,
					haServices,
					heartbeatServices,
					metricRegistry,
					resourceManagerRpcService,
					new ClusterInformation("localhost", blobServer.getPort()),
					jobManagerMetricGroup);

				blobCacheService = new BlobCacheService(
					configuration, haServices.createBlobStore(), new InetSocketAddress(InetAddress.getLocalHost(), blobServer.getPort())
				);

				// bring up the TaskManager(s) for the mini cluster
				LOG.info("Starting {} TaskManger(s)", numTaskManagers);
				taskManagers = startTaskManagers(
					configuration,
					haServices,
					heartbeatServices,
					metricRegistry,
					blobCacheService,
					numTaskManagers,
					taskManagerRpcServices);

				// starting the dispatcher rest endpoint
				LOG.info("Starting dispatcher rest endpoint.");

				dispatcherGatewayRetriever = new RpcGatewayRetriever<>(
					jobManagerRpcService,
					DispatcherGateway.class,
					DispatcherId::fromUuid,
					20,
					Time.milliseconds(20L));
				final RpcGatewayRetriever<ResourceManagerId, ResourceManagerGateway> resourceManagerGatewayRetriever = new RpcGatewayRetriever<>(
					jobManagerRpcService,
					ResourceManagerGateway.class,
					ResourceManagerId::fromUuid,
					20,
					Time.milliseconds(20L));

				this.dispatcherRestEndpoint = new DispatcherRestEndpoint(
					RestServerEndpointConfiguration.fromConfiguration(configuration),
					dispatcherGatewayRetriever,
					configuration,
					RestHandlerConfiguration.fromConfiguration(configuration),
					resourceManagerGatewayRetriever,
					blobServer.getTransientBlobService(),
					WebMonitorEndpoint.createExecutorService(
						configuration.getInteger(RestOptions.SERVER_NUM_THREADS, 1),
						configuration.getInteger(RestOptions.SERVER_THREAD_PRIORITY),
						"DispatcherRestEndpoint"),
					new AkkaQueryServiceRetriever(
						actorSystem,
						Time.milliseconds(configuration.getLong(WebOptions.TIMEOUT))),
					haServices.getWebMonitorLeaderElectionService(),
					new ShutDownFatalErrorHandler());

				dispatcherRestEndpoint.start();

				restAddressURI = new URI(dispatcherRestEndpoint.getRestBaseUrl());

				// bring up the dispatcher that launches JobManagers when jobs submitted
				LOG.info("Starting job dispatcher(s) for JobManger");

				this.jobManagerMetricGroup = MetricUtils.instantiateJobManagerMetricGroup(metricRegistry, "localhost");

				final HistoryServerArchivist historyServerArchivist = HistoryServerArchivist.createHistoryServerArchivist(configuration, dispatcherRestEndpoint);

				dispatcher = new StandaloneDispatcher(
					jobManagerRpcService,
					Dispatcher.DISPATCHER_NAME + UUID.randomUUID(),
					configuration,
					haServices,
					resourceManagerRunner.getResourceManageGateway(),
					blobServer,
					heartbeatServices,
					jobManagerMetricGroup,
					metricRegistry.getMetricQueryServicePath(),
					new MemoryArchivedExecutionGraphStore(),
					Dispatcher.DefaultJobManagerRunnerFactory.INSTANCE,
					new ShutDownFatalErrorHandler(),
					dispatcherRestEndpoint.getRestBaseUrl(),
					historyServerArchivist);

				dispatcher.start();

				resourceManagerLeaderRetriever = haServices.getResourceManagerLeaderRetriever();
				dispatcherLeaderRetriever = haServices.getDispatcherLeaderRetriever();

				resourceManagerLeaderRetriever.start(resourceManagerGatewayRetriever);
				dispatcherLeaderRetriever.start(dispatcherGatewayRetriever);
			}
			catch (Exception e) {
				// cleanup everything
				try {
					close();
				} catch (Exception ee) {
					e.addSuppressed(ee);
				}
				throw e;
			}

			// create a new termination future
			terminationFuture = new CompletableFuture<>();

			// now officially mark this as running
			running = true;

			LOG.info("Flink Mini Cluster started successfully");
		}
	}

• 这里先创建了metricRegistry、commonRpcService、jobManagerRpcService、resourceManagerRpcService、haServices、blobServer、heartbeatServices、resourceManagerRunner、blobCacheService、taskManagers、dispatcherGatewayRetriever、dispatcherRestEndpoint、dispatcher、dispatcherLeaderRetriever

RestServerEndpoint

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/rest/RestServerEndpoint.java

	/**
	 * Starts this REST server endpoint.
	 *
	 * @throws Exception if we cannot start the RestServerEndpoint
	 */
	public final void start() throws Exception {
		synchronized (lock) {
			Preconditions.checkState(state == State.CREATED, "The RestServerEndpoint cannot be restarted.");

			log.info("Starting rest endpoint.");

			final Router router = new Router();
			final CompletableFuture<String> restAddressFuture = new CompletableFuture<>();

			List<Tuple2<RestHandlerSpecification, ChannelInboundHandler>> handlers = initializeHandlers(restAddressFuture);

			/* sort the handlers such that they are ordered the following:
			 * /jobs
			 * /jobs/overview
			 * /jobs/:jobid
			 * /jobs/:jobid/config
			 * /:*
			 */
			Collections.sort(
				handlers,
				RestHandlerUrlComparator.INSTANCE);

			handlers.forEach(handler -> {
				log.debug("Register handler {} under {}@{}.", handler.f1, handler.f0.getHttpMethod(), handler.f0.getTargetRestEndpointURL());
				registerHandler(router, handler);
			});

			ChannelInitializer<SocketChannel> initializer = new ChannelInitializer<SocketChannel>() {

				@Override
				protected void initChannel(SocketChannel ch) {
					RouterHandler handler = new RouterHandler(router, responseHeaders);

					// SSL should be the first handler in the pipeline
					if (sslEngineFactory != null) {
						ch.pipeline().addLast("ssl",
							new RedirectingSslHandler(restAddress, restAddressFuture, sslEngineFactory));
					}

					ch.pipeline()
						.addLast(new HttpServerCodec())
						.addLast(new FileUploadHandler(uploadDir))
						.addLast(new FlinkHttpObjectAggregator(maxContentLength, responseHeaders))
						.addLast(new ChunkedWriteHandler())
						.addLast(handler.getName(), handler)
						.addLast(new PipelineErrorHandler(log, responseHeaders));
				}
			};

			NioEventLoopGroup bossGroup = new NioEventLoopGroup(1, new DefaultThreadFactory("flink-rest-server-netty-boss"));
			NioEventLoopGroup workerGroup = new NioEventLoopGroup(0, new DefaultThreadFactory("flink-rest-server-netty-worker"));

			bootstrap = new ServerBootstrap();
			bootstrap
				.group(bossGroup, workerGroup)
				.channel(NioServerSocketChannel.class)
				.childHandler(initializer);

			log.debug("Binding rest endpoint to {}:{}.", restBindAddress, restBindPort);
			final ChannelFuture channel;
			if (restBindAddress == null) {
				channel = bootstrap.bind(restBindPort);
			} else {
				channel = bootstrap.bind(restBindAddress, restBindPort);
			}
			serverChannel = channel.syncUninterruptibly().channel();

			final InetSocketAddress bindAddress = (InetSocketAddress) serverChannel.localAddress();
			final String advertisedAddress;
			if (bindAddress.getAddress().isAnyLocalAddress()) {
				advertisedAddress = this.restAddress;
			} else {
				advertisedAddress = bindAddress.getAddress().getHostAddress();
			}
			final int port = bindAddress.getPort();

			log.info("Rest endpoint listening at {}:{}", advertisedAddress, port);

			final String protocol;

			if (sslEngineFactory != null) {
				protocol = "https://";
			} else {
				protocol = "http://";
			}

			restBaseUrl = protocol + advertisedAddress + ':' + port;

			restAddressFuture.complete(restBaseUrl);

			state = State.RUNNING;

			startInternal();
		}
	}

• 这里调用了initializeHandlers来获取ChannelInboundHandler，initializeHandlers在子类DispatcherRestEndpoint中有实现

DispatcherRestEndpoint

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/dispatcher/DispatcherRestEndpoint.java

	@Override
	protected List<Tuple2<RestHandlerSpecification, ChannelInboundHandler>> initializeHandlers(CompletableFuture<String> restAddressFuture) {
		List<Tuple2<RestHandlerSpecification, ChannelInboundHandler>> handlers = super.initializeHandlers(restAddressFuture);

		// Add the Dispatcher specific handlers

		final Time timeout = restConfiguration.getTimeout();

		JobSubmitHandler jobSubmitHandler = new JobSubmitHandler(
			restAddressFuture,
			leaderRetriever,
			timeout,
			responseHeaders,
			executor,
			clusterConfiguration);

		if (clusterConfiguration.getBoolean(WebOptions.SUBMIT_ENABLE)) {
			try {
				webSubmissionExtension = WebMonitorUtils.loadWebSubmissionExtension(
					leaderRetriever,
					restAddressFuture,
					timeout,
					responseHeaders,
					uploadDir,
					executor,
					clusterConfiguration);

				// register extension handlers
				handlers.addAll(webSubmissionExtension.getHandlers());
			} catch (FlinkException e) {
				if (log.isDebugEnabled()) {
					log.debug("Failed to load web based job submission extension.", e);
				} else {
					log.info("Failed to load web based job submission extension. " +
						"Probable reason: flink-runtime-web is not in the classpath.");
				}
			}
		} else {
			log.info("Web-based job submission is not enabled.");
		}

		handlers.add(Tuple2.of(jobSubmitHandler.getMessageHeaders(), jobSubmitHandler));

		return handlers;
	}

• 这里首先调用了父类的initializeHandlers，这里的父类为WebMonitorEndpoint(它是RestServerEndpoint的直接子类，而DispatcherRestEndpoint又继承了WebMonitorEndpoint)

WebMonitorEndpoint

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/webmonitor/WebMonitorEndpoint.java

	@Override
	protected List<Tuple2<RestHandlerSpecification, ChannelInboundHandler>> initializeHandlers(CompletableFuture<String> restAddressFuture) {
		ArrayList<Tuple2<RestHandlerSpecification, ChannelInboundHandler>> handlers = new ArrayList<>(30);

		final Time timeout = restConfiguration.getTimeout();

		//......

		// TODO: Remove once the Yarn proxy can forward all REST verbs
		handlers.add(Tuple2.of(YarnCancelJobTerminationHeaders.getInstance(), jobCancelTerminationHandler));
		handlers.add(Tuple2.of(YarnStopJobTerminationHeaders.getInstance(), jobStopTerminationHandler));

		handlers.add(Tuple2.of(shutdownHandler.getMessageHeaders(), shutdownHandler));

		//......

		// load the log and stdout file handler for the main cluster component
		final WebMonitorUtils.LogFileLocation logFileLocation = WebMonitorUtils.LogFileLocation.find(clusterConfiguration);

		final ChannelInboundHandler logFileHandler = createStaticFileHandler(
			restAddressFuture,
			timeout,
			logFileLocation.logFile);

		final ChannelInboundHandler stdoutFileHandler = createStaticFileHandler(
			restAddressFuture,
			timeout,
			logFileLocation.stdOutFile);

		handlers.add(Tuple2.of(LogFileHandlerSpecification.getInstance(), logFileHandler));
		handlers.add(Tuple2.of(StdoutFileHandlerSpecification.getInstance(), stdoutFileHandler));

		// TaskManager log and stdout file handler

		final Time cacheEntryDuration = Time.milliseconds(restConfiguration.getRefreshInterval());

		final TaskManagerLogFileHandler taskManagerLogFileHandler = new TaskManagerLogFileHandler(
			restAddressFuture,
			leaderRetriever,
			timeout,
			responseHeaders,
			TaskManagerLogFileHeaders.getInstance(),
			resourceManagerRetriever,
			transientBlobService,
			cacheEntryDuration);

		final TaskManagerStdoutFileHandler taskManagerStdoutFileHandler = new TaskManagerStdoutFileHandler(
			restAddressFuture,
			leaderRetriever,
			timeout,
			responseHeaders,
			TaskManagerStdoutFileHeaders.getInstance(),
			resourceManagerRetriever,
			transientBlobService,
			cacheEntryDuration);

		handlers.add(Tuple2.of(TaskManagerLogFileHeaders.getInstance(), taskManagerLogFileHandler));
		handlers.add(Tuple2.of(TaskManagerStdoutFileHeaders.getInstance(), taskManagerStdoutFileHandler));

		//......

	}

	@Nonnull
	private ChannelInboundHandler createStaticFileHandler(
			CompletableFuture<String> restAddressFuture,
			Time timeout,
			File fileToServe) {

		if (fileToServe == null) {
			return new ConstantTextHandler("(file unavailable)");
		} else {
			try {
				return new StaticFileServerHandler<>(
					leaderRetriever,
					restAddressFuture,
					timeout,
					fileToServe);
			} catch (IOException e) {
				log.info("Cannot load log file handler.", e);
				return new ConstantTextHandler("(log file unavailable)");
			}
		}
	}

• 它初始化了一系列的ChannelInboundHandler，然后注册到handlers中
• 对于JobManager的FileHandler，它先调用了WebMonitorUtils.LogFileLocation.find(clusterConfiguration)，构建了logFileLocation，之后使用logFileLocation.logFile及logFileLocation.stdOutFile分别构造了logFileHandler、stdoutFileHandler，分别用于处理log及stdout文件的下载
• 对于TaskManager的FileHandler，分别构造了TaskManagerLogFileHandler以及TaskManagerStdoutFileHandler来处理log及stdout文件的下载

JobManager FileHandler

WebMonitorUtils.LogFileLocation.find

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/webmonitor/WebMonitorUtils.java

	/**
	 * Singleton to hold the log and stdout file.
	 */
	public static class LogFileLocation {

		public final File logFile;
		public final File stdOutFile;

		private LogFileLocation(File logFile, File stdOutFile) {
			this.logFile = logFile;
			this.stdOutFile = stdOutFile;
		}

		/**
		 * Finds the Flink log directory using log.file Java property that is set during startup.
		 */
		public static LogFileLocation find(Configuration config) {
			final String logEnv = "log.file";
			String logFilePath = System.getProperty(logEnv);

			if (logFilePath == null) {
				LOG.warn("Log file environment variable '{}' is not set.", logEnv);
				logFilePath = config.getString(WebOptions.LOG_PATH);
			}

			// not configured, cannot serve log files
			if (logFilePath == null || logFilePath.length() < 4) {
				LOG.warn("JobManager log files are unavailable in the web dashboard. " +
					"Log file location not found in environment variable '{}' or configuration key '{}'.",
					logEnv, WebOptions.LOG_PATH);
				return new LogFileLocation(null, null);
			}

			String outFilePath = logFilePath.substring(0, logFilePath.length() - 3).concat("out");

			LOG.info("Determined location of main cluster component log file: {}", logFilePath);
			LOG.info("Determined location of main cluster component stdout file: {}", outFilePath);

			return new LogFileLocation(resolveFileLocation(logFilePath), resolveFileLocation(outFilePath));
		}

		/**
		 * Verify log file location.
		 *
		 * @param logFilePath Path to log file
		 * @return File or null if not a valid log file
		 */
		private static File resolveFileLocation(String logFilePath) {
			File logFile = new File(logFilePath);
			return (logFile.exists() && logFile.canRead()) ? logFile : null;
		}
	}

• 这里先从系统属性读取log.file属性，没有找到，则打印warning(Log file environment variable 'log.file' is not set.)
• log.file没有配置的话，则从flink的Configuration读取WebOptions.LOG_PATH(web.log.path)配置，如果没有或者logFilePath.length()小于4，则打印warning(JobManager log files are unavailable in the web dashboard. Log file location not found in environment variable 'log.file' or configuration key 'Key: 'web.log.path' , default: null (deprecated keys: [jobmanager.web.log.path])'.)
• 这里之所以要logFilePath.length()大于等于4，主要是后面要使用logFilePath.substring(0, logFilePath.length() - 3).concat("out")来构建outFilePath；然后通过resolveFileLocation方法校验logFilePath及outFilePath，构建LogFileLocation返回

StaticFileServerHandler

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/rest/handler/legacy/files/StaticFileServerHandler.java

/**
 * Simple file server handler that serves requests to web frontend's static files, such as
 * HTML, CSS, or JS files.
 *
 * <p>This code is based on the "HttpStaticFileServerHandler" from the Netty project's HTTP server
 * example.</p>
 */
@ChannelHandler.Sharable
public class StaticFileServerHandler<T extends RestfulGateway> extends RedirectHandler<T> {

	/** Timezone in which this server answers its "if-modified" requests. */
	private static final TimeZone GMT_TIMEZONE = TimeZone.getTimeZone("GMT");

	/** Date format for HTTP. */
	public static final String HTTP_DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss zzz";

	/** Be default, we allow files to be cached for 5 minutes. */
	private static final int HTTP_CACHE_SECONDS = 300;

	// ------------------------------------------------------------------------

	/** The path in which the static documents are. */
	private final File rootPath;

	public StaticFileServerHandler(
			GatewayRetriever<? extends T> retriever,
			CompletableFuture<String> localJobManagerAddressFuture,
			Time timeout,
			File rootPath) throws IOException {

		super(localJobManagerAddressFuture, retriever, timeout, Collections.emptyMap());

		this.rootPath = checkNotNull(rootPath).getCanonicalFile();
	}

	// ------------------------------------------------------------------------
	//  Responses to requests
	// ------------------------------------------------------------------------

	@Override
	protected void respondAsLeader(ChannelHandlerContext channelHandlerContext, RoutedRequest routedRequest, T gateway) throws Exception {
		final HttpRequest request = routedRequest.getRequest();
		final String requestPath;

		// make sure we request the "index.html" in case there is a directory request
		if (routedRequest.getPath().endsWith("/")) {
			requestPath = routedRequest.getPath() + "index.html";
		}
		// in case the files being accessed are logs or stdout files, find appropriate paths.
		else if (routedRequest.getPath().equals("/jobmanager/log") || routedRequest.getPath().equals("/jobmanager/stdout")) {
			requestPath = "";
		} else {
			requestPath = routedRequest.getPath();
		}

		respondToRequest(channelHandlerContext, request, requestPath);
	}

	//......

	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
		if (ctx.channel().isActive()) {
			logger.error("Caught exception", cause);
			sendError(ctx, INTERNAL_SERVER_ERROR);
		}
	}
}

• 对于/jobmanager/log以及/jobmanager/stdout它会重置一下requestPath，之后调用respondToRequest处理，它根据rootPath来传输文件

TaskManager FileHandler

TaskManagerLogFileHandler

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/rest/handler/taskmanager/TaskManagerLogFileHandler.java

/**
 * Rest handler which serves the log files from {@link TaskExecutor}.
 */
public class TaskManagerLogFileHandler extends AbstractTaskManagerFileHandler<TaskManagerMessageParameters> {

	public TaskManagerLogFileHandler(
			@Nonnull CompletableFuture<String> localAddressFuture,
			@Nonnull GatewayRetriever<? extends RestfulGateway> leaderRetriever,
			@Nonnull Time timeout,
			@Nonnull Map<String, String> responseHeaders,
			@Nonnull UntypedResponseMessageHeaders<EmptyRequestBody, TaskManagerMessageParameters> untypedResponseMessageHeaders,
			@Nonnull GatewayRetriever<ResourceManagerGateway> resourceManagerGatewayRetriever,
			@Nonnull TransientBlobService transientBlobService,
			@Nonnull Time cacheEntryDuration) {
		super(localAddressFuture, leaderRetriever, timeout, responseHeaders, untypedResponseMessageHeaders, resourceManagerGatewayRetriever, transientBlobService, cacheEntryDuration);
	}

	@Override
	protected CompletableFuture<TransientBlobKey> requestFileUpload(ResourceManagerGateway resourceManagerGateway, ResourceID taskManagerResourceId) {
		return resourceManagerGateway.requestTaskManagerFileUpload(taskManagerResourceId, FileType.LOG, timeout);
	}
}

• 它的requestFileUpload是调用了ResourceManager.requestTaskManagerFileUpload，传递的FileType是FileType.LOG类型

TaskManagerStdoutFileHandler.requestFileUpload

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/rest/handler/taskmanager/TaskManagerStdoutFileHandler.java

/**
 * Rest handler which serves the stdout file of the {@link TaskExecutor}.
 */
public class TaskManagerStdoutFileHandler extends AbstractTaskManagerFileHandler<TaskManagerMessageParameters> {

	public TaskManagerStdoutFileHandler(
			@Nonnull CompletableFuture<String> localAddressFuture,
			@Nonnull GatewayRetriever<? extends RestfulGateway> leaderRetriever,
			@Nonnull Time timeout,
			@Nonnull Map<String, String> responseHeaders,
			@Nonnull UntypedResponseMessageHeaders<EmptyRequestBody, TaskManagerMessageParameters> untypedResponseMessageHeaders,
			@Nonnull GatewayRetriever<ResourceManagerGateway> resourceManagerGatewayRetriever,
			@Nonnull TransientBlobService transientBlobService,
			@Nonnull Time cacheEntryDuration) {
		super(localAddressFuture, leaderRetriever, timeout, responseHeaders, untypedResponseMessageHeaders, resourceManagerGatewayRetriever, transientBlobService, cacheEntryDuration);
	}

	@Override
	protected CompletableFuture<TransientBlobKey> requestFileUpload(ResourceManagerGateway resourceManagerGateway, ResourceID taskManagerResourceId) {
		return resourceManagerGateway.requestTaskManagerFileUpload(taskManagerResourceId, FileType.STDOUT, timeout);
	}
}

• 它的requestFileUpload是调用了ResourceManager.requestTaskManagerFileUpload，传递的FileType是FileType.STDOUT类型

ResourceManager.requestTaskManagerFileUpload

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/resourcemanager/ResourceManager.java

	@Override
	public CompletableFuture<TransientBlobKey> requestTaskManagerFileUpload(ResourceID taskManagerId, FileType fileType, Time timeout) {
		log.debug("Request file {} upload from TaskExecutor {}.", fileType, taskManagerId);

		final WorkerRegistration<WorkerType> taskExecutor = taskExecutors.get(taskManagerId);

		if (taskExecutor == null) {
			log.debug("Requested file {} upload from unregistered TaskExecutor {}.", fileType, taskManagerId);
			return FutureUtils.completedExceptionally(new UnknownTaskExecutorException(taskManagerId));
		} else {
			return taskExecutor.getTaskExecutorGateway().requestFileUpload(fileType, timeout);
		}
	}

• ResourceManager的requestTaskManagerFileUpload是通过TaskExecutor.requestFileUpload来实现的

TaskExecutor.requestFileUpload

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/taskexecutor/TaskExecutor.java

	@Override
	public CompletableFuture<TransientBlobKey> requestFileUpload(FileType fileType, Time timeout) {
		log.debug("Request file {} upload.", fileType);

		final String filePath;

		switch (fileType) {
			case LOG:
				filePath = taskManagerConfiguration.getTaskManagerLogPath();
				break;
			case STDOUT:
				filePath = taskManagerConfiguration.getTaskManagerStdoutPath();
				break;
			default:
				filePath = null;
		}

		if (filePath != null && !filePath.isEmpty()) {
			final File file = new File(filePath);

			if (file.exists()) {
				final TransientBlobCache transientBlobService = blobCacheService.getTransientBlobService();
				final TransientBlobKey transientBlobKey;
				try (FileInputStream fileInputStream = new FileInputStream(file)) {
					transientBlobKey = transientBlobService.putTransient(fileInputStream);
				} catch (IOException e) {
					log.debug("Could not upload file {}.", fileType, e);
					return FutureUtils.completedExceptionally(new FlinkException("Could not upload file " + fileType + '.', e));
				}

				return CompletableFuture.completedFuture(transientBlobKey);
			} else {
				log.debug("The file {} does not exist on the TaskExecutor {}.", fileType, getResourceID());
				return FutureUtils.completedExceptionally(new FlinkException("The file " + fileType + " does not exist on the TaskExecutor."));
			}
		} else {
			log.debug("The file {} is unavailable on the TaskExecutor {}.", fileType, getResourceID());
			return FutureUtils.completedExceptionally(new FlinkException("The file " + fileType + " is not available on the TaskExecutor."));
		}
	}

• TaskExecutor的requestFileUpload会根据fileType来获取filePath，如果是LOG类型取的是taskManagerConfiguration.getTaskManagerLogPath()；如果是STDOUT类型，取的是taskManagerConfiguration.getTaskManagerStdoutPath()，之后将文件传输过去

TaskManagerRunner.startTaskManager

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/taskexecutor/TaskManagerRunner.java

	public static TaskExecutor startTaskManager(
			Configuration configuration,
			ResourceID resourceID,
			RpcService rpcService,
			HighAvailabilityServices highAvailabilityServices,
			HeartbeatServices heartbeatServices,
			MetricRegistry metricRegistry,
			BlobCacheService blobCacheService,
			boolean localCommunicationOnly,
			FatalErrorHandler fatalErrorHandler) throws Exception {

		checkNotNull(configuration);
		checkNotNull(resourceID);
		checkNotNull(rpcService);
		checkNotNull(highAvailabilityServices);

		LOG.info("Starting TaskManager with ResourceID: {}", resourceID);

		InetAddress remoteAddress = InetAddress.getByName(rpcService.getAddress());

		TaskManagerServicesConfiguration taskManagerServicesConfiguration =
			TaskManagerServicesConfiguration.fromConfiguration(
				configuration,
				remoteAddress,
				localCommunicationOnly);

		TaskManagerServices taskManagerServices = TaskManagerServices.fromConfiguration(
			taskManagerServicesConfiguration,
			resourceID,
			rpcService.getExecutor(), // TODO replace this later with some dedicated executor for io.
			EnvironmentInformation.getSizeOfFreeHeapMemoryWithDefrag(),
			EnvironmentInformation.getMaxJvmHeapMemory());

		TaskManagerMetricGroup taskManagerMetricGroup = MetricUtils.instantiateTaskManagerMetricGroup(
			metricRegistry,
			taskManagerServices.getTaskManagerLocation(),
			taskManagerServices.getNetworkEnvironment());

		TaskManagerConfiguration taskManagerConfiguration = TaskManagerConfiguration.fromConfiguration(configuration);

		return new TaskExecutor(
			rpcService,
			taskManagerConfiguration,
			highAvailabilityServices,
			taskManagerServices,
			heartbeatServices,
			taskManagerMetricGroup,
			blobCacheService,
			fatalErrorHandler);
	}

• TaskManagerRunner.startTaskManager通过TaskManagerConfiguration.fromConfiguration(configuration)构造了taskManagerConfiguration

TaskManagerConfiguration.fromConfiguration

flink-runtime_2.11-1.6.2-sources.jar!/org/apache/flink/runtime/taskexecutor/TaskManagerConfiguration.java

	public static TaskManagerConfiguration fromConfiguration(Configuration configuration) {
		int numberSlots = configuration.getInteger(TaskManagerOptions.NUM_TASK_SLOTS, 1);

		if (numberSlots == -1) {
			numberSlots = 1;
		}

		//......

		final String taskManagerLogPath = configuration.getString(ConfigConstants.TASK_MANAGER_LOG_PATH_KEY, System.getProperty("log.file"));
		final String taskManagerStdoutPath;

		if (taskManagerLogPath != null) {
			final int extension = taskManagerLogPath.lastIndexOf('.');

			if (extension > 0) {
				taskManagerStdoutPath = taskManagerLogPath.substring(0, extension) + ".out";
			} else {
				taskManagerStdoutPath = null;
			}
		} else {
			taskManagerStdoutPath = null;
		}

		return new TaskManagerConfiguration(
			numberSlots,
			tmpDirPaths,
			timeout,
			finiteRegistrationDuration,
			initialRegistrationPause,
			maxRegistrationPause,
			refusedRegistrationPause,
			configuration,
			exitOnOom,
			FlinkUserCodeClassLoaders.ResolveOrder.fromString(classLoaderResolveOrder),
			alwaysParentFirstLoaderPatterns,
			taskManagerLogPath,
			taskManagerStdoutPath);
	}

• TaskManagerConfiguration.fromConfiguration里头首先根据ConfigConstants.TASK_MANAGER_LOG_PATH_KEY(taskmanager.log.path)从flink的Configuration读取taskManagerLogPath，如果读取不到，则取系统属性log.file；如果读取到taskManagerLogPath不为null，则换个后缀构建taskManagerStdoutPath

小结

• flink的log4j.properties里头配置了file appender，使用了系统属性log.file
• flink的MiniCluster在start的时候会创建DispatcherRestEndpoint，它的start方法会使用initializeHandlers来初始化一系列的handlers，对于JobManager的fileHandler，使用WebMonitorUtils.LogFileLocation.find(clusterConfiguration)获取logFileLocation，它先从系统属性读取log.file属性，没有找到的话再从flink的Configuration读取WebOptions.LOG_PATH(web.log.path)配置；之后分别使用logFileLocation.logFile及logFileLocation.stdOutFile创建了两个StaticFileServerHandler
• 对于TaskManager的fileHandler，则分别创建了TaskManagerLogFileHandler及TaskManagerStdoutFileHandler来处理log及stdout文件的下载，它们内部都是调用了ResourceManager.requestTaskManagerFileUpload方法，只是fileType不同，一个是LOG，一个是STDOUT；而ResourceManager.requestTaskManagerFileUpload方法最后是通过TaskExecutor.requestFileUpload来完成文件传输；TaskManagerRunner.startTaskManager在创建TaskExecutor的时候，构造了TaskManagerConfiguration，它里头先从flink的Configuration获取ConfigConstants.TASK_MANAGER_LOG_PATH_KEY(taskmanager.log.path)，如果没有则取系统属性log.file

doc

• How to use logging