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From fhue...@apache.org
Subject [40/51] [abbrv] [partial] flink git commit: [FLINK-4676] [connectors] Merge batch and streaming connectors into common Maven module.
Date Fri, 02 Dec 2016 13:35:30 GMT
http://git-wip-us.apache.org/repos/asf/flink/blob/de4fe3b7/flink-connectors/flink-connector-filesystem/src/main/java/org/apache/flink/streaming/connectors/fs/bucketing/BucketingSink.java
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diff --git a/flink-connectors/flink-connector-filesystem/src/main/java/org/apache/flink/streaming/connectors/fs/bucketing/BucketingSink.java b/flink-connectors/flink-connector-filesystem/src/main/java/org/apache/flink/streaming/connectors/fs/bucketing/BucketingSink.java
new file mode 100644
index 0000000..cf2c373
--- /dev/null
+++ b/flink-connectors/flink-connector-filesystem/src/main/java/org/apache/flink/streaming/connectors/fs/bucketing/BucketingSink.java
@@ -0,0 +1,1082 @@
+/*
+ * 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.streaming.connectors.fs.bucketing;
+
+import org.apache.commons.lang3.time.StopWatch;
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.state.ListState;
+import org.apache.flink.api.common.state.OperatorStateStore;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.java.typeutils.InputTypeConfigurable;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.runtime.fs.hdfs.HadoopFileSystem;
+import org.apache.flink.runtime.state.CheckpointListener;
+import org.apache.flink.runtime.state.FunctionInitializationContext;
+import org.apache.flink.runtime.state.FunctionSnapshotContext;
+import org.apache.flink.streaming.api.checkpoint.CheckpointedFunction;
+import org.apache.flink.streaming.api.functions.sink.RichSinkFunction;
+import org.apache.flink.streaming.api.operators.StreamingRuntimeContext;
+import org.apache.flink.streaming.connectors.fs.Clock;
+import org.apache.flink.streaming.connectors.fs.SequenceFileWriter;
+import org.apache.flink.streaming.connectors.fs.StringWriter;
+import org.apache.flink.streaming.connectors.fs.Writer;
+import org.apache.flink.streaming.runtime.tasks.ProcessingTimeCallback;
+import org.apache.flink.streaming.runtime.tasks.ProcessingTimeService;
+import org.apache.flink.util.Preconditions;
+import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.DistributedFileSystem;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import java.util.Iterator;
+
+/**
+ * Sink that emits its input elements to {@link org.apache.hadoop.fs.FileSystem} files within
+ * buckets. This is integrated with the checkpointing mechanism to provide exactly once semantics.
+ *
+ * <p>
+ * When creating the sink a {@code basePath} must be specified. The base directory contains
+ * one directory for every bucket. The bucket directories themselves contain several part files,
+ * one for each parallel subtask of the sink. These part files contain the actual output data.
+ *
+ * <p>
+ * The sink uses a {@link Bucketer} to determine in which bucket directory each element should
+ * be written to inside the base directory. The {@code Bucketer} can, for example, use time or
+ * a property of the element to determine the bucket directory. The default {@code Bucketer} is a
+ * {@link DateTimeBucketer} which will create one new bucket every hour. You can specify
+ * a custom {@code Bucketer} using {@link #setBucketer(Bucketer)}. For example, use the
+ * {@link BasePathBucketer} if you don't want to have buckets but still want to write part-files
+ * in a fault-tolerant way.
+ *
+ * <p>
+ * The filenames of the part files contain the part prefix, the parallel subtask index of the sink
+ * and a rolling counter. For example the file {@code "part-1-17"} contains the data from
+ * {@code subtask 1} of the sink and is the {@code 17th} bucket created by that subtask. Per default
+ * the part prefix is {@code "part"} but this can be configured using {@link #setPartPrefix(String)}.
+ * When a part file becomes bigger than the user-specified batch size the current part file is closed,
+ * the part counter is increased and a new part file is created. The batch size defaults to {@code 384MB},
+ * this can be configured using {@link #setBatchSize(long)}.
+ *
+ * <p>
+ * In some scenarios, the open buckets are required to change based on time. In these cases, the sink
+ * needs to determine when a bucket has become inactive, in order to flush and close the part file.
+ * To support this there are two configurable settings:
+ * <ol>
+ *     <li>the frequency to check for inactive buckets, configured by {@link #setInactiveBucketCheckInterval(long)},
+ *     and</li>
+ *     <li>the minimum amount of time a bucket has to not receive any data before it is considered inactive,
+ *     configured by {@link #setInactiveBucketThreshold(long)}</li>
+ * </ol>
+ * Both of these parameters default to {@code 60,000 ms}, or {@code 1 min}.
+ *
+ * <p>
+ * Part files can be in one of three states: {@code in-progress}, {@code pending} or {@code finished}.
+ * The reason for this is how the sink works together with the checkpointing mechanism to provide exactly-once
+ * semantics and fault-tolerance. The part file that is currently being written to is {@code in-progress}. Once
+ * a part file is closed for writing it becomes {@code pending}. When a checkpoint is successful the currently
+ * pending files will be moved to {@code finished}.
+ *
+ * <p>
+ * If case of a failure, and in order to guarantee exactly-once semantics, the sink should roll back to the state it
+ * had when that last successful checkpoint occurred. To this end, when restoring, the restored files in {@code pending}
+ * state are transferred into the {@code finished} state while any {@code in-progress} files are rolled back, so that
+ * they do not contain data that arrived after the checkpoint from which we restore. If the {@code FileSystem} supports
+ * the {@code truncate()} method this will be used to reset the file back to its previous state. If not, a special
+ * file with the same name as the part file and the suffix {@code ".valid-length"} will be created that contains the
+ * length up to which the file contains valid data. When reading the file, it must be ensured that it is only read up
+ * to that point. The prefixes and suffixes for the different file states and valid-length files can be configured
+ * using the adequate setter method, e.g. {@link #setPendingSuffix(String)}.
+ *
+ * <p>
+ * <b>NOTE:</b>
+ * <ol>
+ *     <li>
+ *         If checkpointing is not enabled the pending files will never be moved to the finished state. In that case,
+ *         the pending suffix/prefix can be set to {@code ""} to make the sink work in a non-fault-tolerant way but
+ *         still provide output without prefixes and suffixes.
+ *     </li>
+ *     <li>
+ *         The part files are written using an instance of {@link Writer}. By default, a
+ *         {@link org.apache.flink.streaming.connectors.fs.StringWriter} is used, which writes the result
+ *         of {@code toString()} for every element, separated by newlines. You can configure the writer using  the
+ *         {@link #setWriter(Writer)}. For example, {@link org.apache.flink.streaming.connectors.fs.SequenceFileWriter}
+ *         can be used to write Hadoop {@code SequenceFiles}.
+ *     </li>
+ * </ol>
+ *
+ * <p>
+ * Example:
+ * <pre>{@code
+ *     new BucketingSink<Tuple2<IntWritable, Text>>(outPath)
+ *         .setWriter(new SequenceFileWriter<IntWritable, Text>())
+ *         .setBucketer(new DateTimeBucketer("yyyy-MM-dd--HHmm")
+ * }</pre>
+ *
+ * This will create a sink that writes to {@code SequenceFiles} and rolls every minute.
+ *
+ * @see DateTimeBucketer
+ * @see StringWriter
+ * @see SequenceFileWriter
+ *
+ * @param <T> Type of the elements emitted by this sink
+ */
+public class BucketingSink<T>
+		extends RichSinkFunction<T>
+		implements InputTypeConfigurable, CheckpointedFunction, CheckpointListener, ProcessingTimeCallback {
+
+	private static final long serialVersionUID = 1L;
+
+	private static Logger LOG = LoggerFactory.getLogger(BucketingSink.class);
+
+	// --------------------------------------------------------------------------------------------
+	//  User configuration values
+	// --------------------------------------------------------------------------------------------
+	// These are initialized with some defaults but are meant to be changeable by the user
+
+	/**
+	 * The default maximum size of part files (currently {@code 384 MB}).
+	 */
+	private final long DEFAULT_BATCH_SIZE = 1024L * 1024L * 384L;
+
+	/**
+	 * The default time between checks for inactive buckets. By default, {60 sec}.
+	 */
+	private final long DEFAULT_INACTIVE_BUCKET_CHECK_INTERVAL_MS = 60 * 1000L;
+
+	/**
+	 * The default threshold (in {@code ms}) for marking a bucket as inactive and
+	 * closing its part files. By default, {60 sec}.
+	 */
+	private final long DEFAULT_INACTIVE_BUCKET_THRESHOLD_MS = 60 * 1000L;
+
+	/**
+	 * The suffix for {@code in-progress} part files. These are files we are
+	 * currently writing to, but which were not yet confirmed by a checkpoint.
+	 */
+	private final String DEFAULT_IN_PROGRESS_SUFFIX = ".in-progress";
+
+	/**
+	 * The prefix for {@code in-progress} part files. These are files we are
+	 * currently writing to, but which were not yet confirmed by a checkpoint.
+	 */
+	private final String DEFAULT_IN_PROGRESS_PREFIX = "_";
+
+	/**
+	 * The suffix for {@code pending} part files. These are closed files that we are
+	 * not currently writing to (inactive or reached {@link #batchSize}), but which
+	 * were not yet confirmed by a checkpoint.
+	 */
+	private final String DEFAULT_PENDING_SUFFIX = ".pending";
+
+	/**
+	 * The prefix for {@code pending} part files. These are closed files that we are
+	 * not currently writing to (inactive or reached {@link #batchSize}), but which
+	 * were not yet confirmed by a checkpoint.
+	 */
+	private final String DEFAULT_PENDING_PREFIX = "_";
+
+	/**
+	 * When {@code truncate()} is not supported by the used {@link FileSystem}, we create
+	 * a file along the part file with this suffix that contains the length up to which
+	 * the part file is valid.
+	 */
+	private final String DEFAULT_VALID_SUFFIX = ".valid-length";
+
+	/**
+	 * When {@code truncate()} is not supported by the used {@link FileSystem}, we create
+	 * a file along the part file with this preffix that contains the length up to which
+	 * the part file is valid.
+	 */
+	private final String DEFAULT_VALID_PREFIX = "_";
+
+	/**
+	 * The default prefix for part files.
+	 */
+	private final String DEFAULT_PART_REFIX = "part";
+
+	/**
+	 * The default timeout for asynchronous operations such as recoverLease and truncate (in {@code ms}).
+	 */
+	private final long DEFAULT_ASYNC_TIMEOUT_MS = 60 * 1000;
+
+
+	/**
+	 * The base {@code Path} that stores all bucket directories.
+	 */
+	private final String basePath;
+
+	/**
+	 * The {@code Bucketer} that is used to determine the path of bucket directories.
+	 */
+	private Bucketer<T> bucketer;
+
+	/**
+	 * We have a template and call duplicate() for each parallel writer in open() to get the actual
+	 * writer that is used for the part files.
+	 */
+	private Writer<T> writerTemplate;
+
+	private long batchSize = DEFAULT_BATCH_SIZE;
+	private long inactiveBucketCheckInterval = DEFAULT_INACTIVE_BUCKET_CHECK_INTERVAL_MS;
+	private long inactiveBucketThreshold = DEFAULT_INACTIVE_BUCKET_THRESHOLD_MS;
+
+	// These are the actually configured prefixes/suffixes
+	private String inProgressSuffix = DEFAULT_IN_PROGRESS_SUFFIX;
+	private String inProgressPrefix = DEFAULT_IN_PROGRESS_PREFIX;
+
+	private String pendingSuffix = DEFAULT_PENDING_SUFFIX;
+	private String pendingPrefix = DEFAULT_PENDING_PREFIX;
+
+	private String validLengthSuffix = DEFAULT_VALID_SUFFIX;
+	private String validLengthPrefix= DEFAULT_VALID_PREFIX;
+
+	private String partPrefix = DEFAULT_PART_REFIX;
+
+	/**
+	 * The timeout for asynchronous operations such as recoverLease and truncate (in {@code ms}).
+	 */
+	private long asyncTimeout = DEFAULT_ASYNC_TIMEOUT_MS;
+
+	// --------------------------------------------------------------------------------------------
+	//  Internal fields (not configurable by user)
+	// -------------------------------------------ยง-------------------------------------------------
+
+	/**
+	 * We use reflection to get the .truncate() method, this is only available starting with Hadoop 2.7
+	 */
+	private transient Method refTruncate;
+
+	/**
+	 * The state object that is handled by Flink from snapshot/restore. This contains state for
+	 * every open bucket: the current in-progress part file path, its valid length and the pending part files.
+	 */
+	private transient State<T> state;
+
+	private transient ListState<State<T>> restoredBucketStates;
+
+	/**
+	 * User-defined FileSystem parameters
+	 */
+	private Configuration fsConfig;
+
+	/**
+	 * The FileSystem reference.
+	 */
+	private transient FileSystem fs;
+
+	private transient Clock clock;
+
+	private transient ProcessingTimeService processingTimeService;
+
+	/**
+	 * Creates a new {@code BucketingSink} that writes files to the given base directory.
+	 *
+	 * <p>
+	 * This uses a{@link DateTimeBucketer} as {@link Bucketer} and a {@link StringWriter} has writer.
+	 * The maximum bucket size is set to 384 MB.
+	 *
+	 * @param basePath The directory to which to write the bucket files.
+	 */
+	public BucketingSink(String basePath) {
+		this.basePath = basePath;
+		this.bucketer = new DateTimeBucketer<>();
+		this.writerTemplate = new StringWriter<>();
+	}
+
+	/**
+	 * Specify a custom {@code Configuration} that will be used when creating
+	 * the {@link FileSystem} for writing.
+	 */
+	public BucketingSink<T> setFSConfig(Configuration config) {
+		this.fsConfig = new Configuration();
+		fsConfig.addAll(config);
+		return this;
+	}
+
+	/**
+	 * Specify a custom {@code Configuration} that will be used when creating
+	 * the {@link FileSystem} for writing.
+	 */
+	public BucketingSink<T> setFSConfig(org.apache.hadoop.conf.Configuration config) {
+		this.fsConfig = new Configuration();
+		for(Map.Entry<String, String> entry : config) {
+			fsConfig.setString(entry.getKey(), entry.getValue());
+		}
+		return this;
+	}
+
+	@Override
+	@SuppressWarnings("unchecked")
+	public void setInputType(TypeInformation<?> type, ExecutionConfig executionConfig) {
+		if (this.writerTemplate instanceof InputTypeConfigurable) {
+			((InputTypeConfigurable) writerTemplate).setInputType(type, executionConfig);
+		}
+	}
+
+	@Override
+	public void initializeState(FunctionInitializationContext context) throws Exception {
+		Preconditions.checkArgument(this.restoredBucketStates == null, "The operator has already been initialized.");
+
+		initFileSystem();
+
+		if (this.refTruncate == null) {
+			this.refTruncate = reflectTruncate(fs);
+		}
+
+		OperatorStateStore stateStore = context.getOperatorStateStore();
+		restoredBucketStates = stateStore.getSerializableListState("bucket-states");
+
+		int subtaskIndex = getRuntimeContext().getIndexOfThisSubtask();
+		if (context.isRestored()) {
+			LOG.info("Restoring state for the {} (taskIdx={}).", getClass().getSimpleName(), subtaskIndex);
+
+			for (State<T> recoveredState : restoredBucketStates.get()) {
+				handleRestoredBucketState(recoveredState);
+				if (LOG.isDebugEnabled()) {
+					LOG.debug("{} idx {} restored {}", getClass().getSimpleName(), subtaskIndex, recoveredState);
+				}
+			}
+		} else {
+			LOG.info("No state to restore for the {} (taskIdx={}).", getClass().getSimpleName(), subtaskIndex);
+		}
+	}
+
+	@Override
+	public void open(Configuration parameters) throws Exception {
+		super.open(parameters);
+
+		state = new State<>();
+
+		processingTimeService =
+				((StreamingRuntimeContext) getRuntimeContext()).getProcessingTimeService();
+
+		long currentProcessingTime = processingTimeService.getCurrentProcessingTime();
+
+		processingTimeService.registerTimer(currentProcessingTime + inactiveBucketCheckInterval, this);
+
+		this.clock = new Clock() {
+			@Override
+			public long currentTimeMillis() {
+				return processingTimeService.getCurrentProcessingTime();
+			}
+		};
+	}
+
+	/**
+	 * Create a file system with the user-defined {@code HDFS} configuration.
+	 * @throws IOException
+	 */
+	private void initFileSystem() throws IOException {
+		if (fs != null) {
+			return;
+		}
+		org.apache.hadoop.conf.Configuration hadoopConf = HadoopFileSystem.getHadoopConfiguration();
+		if (fsConfig != null) {
+			String disableCacheName = String.format("fs.%s.impl.disable.cache", new Path(basePath).toUri().getScheme());
+			hadoopConf.setBoolean(disableCacheName, true);
+			for (String key : fsConfig.keySet()) {
+				hadoopConf.set(key, fsConfig.getString(key, null));
+			}
+		}
+
+		fs = new Path(basePath).getFileSystem(hadoopConf);
+	}
+
+	@Override
+	public void close() throws Exception {
+		for (Map.Entry<String, BucketState<T>> entry : state.bucketStates.entrySet()) {
+			closeCurrentPartFile(entry.getValue());
+		}
+	}
+
+	@Override
+	public void invoke(T value) throws Exception {
+		Path bucketPath = bucketer.getBucketPath(clock, new Path(basePath), value);
+
+		long currentProcessingTime = processingTimeService.getCurrentProcessingTime();
+
+		BucketState<T> bucketState = state.getBucketState(bucketPath);
+		if (bucketState == null) {
+			bucketState = new BucketState<>(currentProcessingTime);
+			state.addBucketState(bucketPath, bucketState);
+		}
+
+		if (shouldRoll(bucketState)) {
+			openNewPartFile(bucketPath, bucketState);
+		}
+
+		bucketState.writer.write(value);
+		bucketState.lastWrittenToTime = currentProcessingTime;
+	}
+
+	/**
+	 * Returns {@code true} if the current {@code part-file} should be closed and a new should be created.
+	 * This happens if:
+	 * <ol>
+	 *     <li>no file is created yet for the task to write to, or</li>
+	 *     <li>the current file has reached the maximum bucket size.</li>
+	 * </ol>
+	 */
+	private boolean shouldRoll(BucketState<T> bucketState) throws IOException {
+		boolean shouldRoll = false;
+		int subtaskIndex = getRuntimeContext().getIndexOfThisSubtask();
+		if (!bucketState.isWriterOpen) {
+			shouldRoll = true;
+			LOG.debug("BucketingSink {} starting new bucket.", subtaskIndex);
+		} else {
+			long writePosition = bucketState.writer.getPos();
+			if (writePosition > batchSize) {
+				shouldRoll = true;
+				LOG.debug(
+					"BucketingSink {} starting new bucket because file position {} is above batch size {}.",
+					subtaskIndex,
+					writePosition,
+					batchSize);
+			}
+		}
+		return shouldRoll;
+	}
+
+	@Override
+	public void onProcessingTime(long timestamp) throws Exception {
+		long currentProcessingTime = processingTimeService.getCurrentProcessingTime();
+
+		checkForInactiveBuckets(currentProcessingTime);
+
+		processingTimeService.registerTimer(currentProcessingTime + inactiveBucketCheckInterval, this);
+	}
+
+	/**
+	 * Checks for inactive buckets, and closes them. Buckets are considered inactive if they have not been
+	 * written to for a period greater than {@code inactiveBucketThreshold} ms. This enables in-progress
+	 * files to be moved to the pending state and be finalised on the next checkpoint.
+	 */
+	private void checkForInactiveBuckets(long currentProcessingTime) throws Exception {
+
+		synchronized (state.bucketStates) {
+			for (Map.Entry<String, BucketState<T>> entry : state.bucketStates.entrySet()) {
+				if (entry.getValue().lastWrittenToTime < currentProcessingTime - inactiveBucketThreshold) {
+					LOG.debug("BucketingSink {} closing bucket due to inactivity of over {} ms.",
+						getRuntimeContext().getIndexOfThisSubtask(), inactiveBucketThreshold);
+					closeCurrentPartFile(entry.getValue());
+				}
+			}
+		}
+	}
+
+	/**
+	 * Closes the current part file and opens a new one with a new bucket path, as returned by the
+	 * {@link Bucketer}. If the bucket is not new, then this will create a new file with the same path
+	 * as its predecessor, but with an increased rolling counter (see {@link BucketingSink}.
+	 */
+	private void openNewPartFile(Path bucketPath, BucketState<T> bucketState) throws Exception {
+		closeCurrentPartFile(bucketState);
+
+		if (!fs.exists(bucketPath)) {
+			try {
+				if (fs.mkdirs(bucketPath)) {
+					LOG.debug("Created new bucket directory: {}", bucketPath);
+				}
+			} catch (IOException e) {
+				throw new RuntimeException("Could not create new bucket path.", e);
+			}
+		}
+
+		// The following loop tries different partCounter values in ascending order until it reaches the minimum
+		// that is not yet used. This works since there is only one parallel subtask that tries names with this
+		// subtask id. Otherwise we would run into concurrency issues here. This is aligned with the way we now
+		// clean the base directory in case of rescaling.
+
+		int subtaskIndex = getRuntimeContext().getIndexOfThisSubtask();
+		Path partPath = new Path(bucketPath, partPrefix + "-" + subtaskIndex + "-" + bucketState.partCounter);
+		while (fs.exists(partPath) ||
+				fs.exists(getPendingPathFor(partPath)) ||
+				fs.exists(getInProgressPathFor(partPath))) {
+			bucketState.partCounter++;
+			partPath = new Path(bucketPath, partPrefix + "-" + subtaskIndex + "-" + bucketState.partCounter);
+		}
+
+		// increase, so we don't have to check for this name next time
+		bucketState.partCounter++;
+
+		LOG.debug("Next part path is {}", partPath.toString());
+		bucketState.currentFile = partPath.toString();
+
+		Path inProgressPath = getInProgressPathFor(partPath);
+		if (bucketState.writer == null) {
+			bucketState.writer = writerTemplate.duplicate();
+		}
+
+		bucketState.writer.open(fs, inProgressPath);
+		bucketState.isWriterOpen = true;
+	}
+
+	/**
+	 * Closes the current part file and moves it from the in-progress state to the pending state.
+	 */
+	private void closeCurrentPartFile(BucketState<T> bucketState) throws Exception {
+		if (bucketState.isWriterOpen) {
+			bucketState.writer.close();
+			bucketState.isWriterOpen = false;
+		}
+
+		if (bucketState.currentFile != null) {
+			Path currentPartPath = new Path(bucketState.currentFile);
+			Path inProgressPath = getInProgressPathFor(currentPartPath);
+			Path pendingPath = getPendingPathFor(currentPartPath);
+
+			fs.rename(inProgressPath, pendingPath);
+			LOG.debug("Moving in-progress bucket {} to pending file {}",
+				inProgressPath,
+				pendingPath);
+			bucketState.pendingFiles.add(currentPartPath.toString());
+			bucketState.currentFile = null;
+		}
+	}
+
+	/**
+	 * Gets the truncate() call using reflection.
+	 * <p>
+	 * <b>NOTE:</b> This code comes from Flume.
+	 */
+	private Method reflectTruncate(FileSystem fs) {
+		Method m = null;
+		if(fs != null) {
+			Class<?> fsClass = fs.getClass();
+			try {
+				m = fsClass.getMethod("truncate", Path.class, long.class);
+			} catch (NoSuchMethodException ex) {
+				LOG.debug("Truncate not found. Will write a file with suffix '{}' " +
+					" and prefix '{}' to specify how many bytes in a bucket are valid.", validLengthSuffix, validLengthPrefix);
+				return null;
+			}
+
+			// verify that truncate actually works
+			FSDataOutputStream outputStream;
+			Path testPath = new Path(UUID.randomUUID().toString());
+			try {
+				outputStream = fs.create(testPath);
+				outputStream.writeUTF("hello");
+				outputStream.close();
+			} catch (IOException e) {
+				LOG.error("Could not create file for checking if truncate works.", e);
+				throw new RuntimeException("Could not create file for checking if truncate works.", e);
+			}
+
+			try {
+				m.invoke(fs, testPath, 2);
+			} catch (IllegalAccessException | InvocationTargetException e) {
+				LOG.debug("Truncate is not supported.", e);
+				m = null;
+			}
+
+			try {
+				fs.delete(testPath, false);
+			} catch (IOException e) {
+				LOG.error("Could not delete truncate test file.", e);
+				throw new RuntimeException("Could not delete truncate test file.", e);
+			}
+		}
+		return m;
+	}
+
+	private Path getPendingPathFor(Path path) {
+		return new Path(path.getParent(), pendingPrefix + path.getName()).suffix(pendingSuffix);
+	}
+
+	private Path getInProgressPathFor(Path path) {
+		return new Path(path.getParent(), inProgressPrefix + path.getName()).suffix(inProgressSuffix);
+	}
+
+	private Path getValidLengthPathFor(Path path) {
+		return new Path(path.getParent(), validLengthPrefix + path.getName()).suffix(validLengthSuffix);
+	}
+
+	@Override
+	public void notifyCheckpointComplete(long checkpointId) throws Exception {
+		synchronized (state.bucketStates) {
+
+			Iterator<Map.Entry<String, BucketState<T>>> bucketStatesIt = state.bucketStates.entrySet().iterator();
+			while (bucketStatesIt.hasNext()) {
+				BucketState<T> bucketState = bucketStatesIt.next().getValue();
+				synchronized (bucketState.pendingFilesPerCheckpoint) {
+
+					Iterator<Map.Entry<Long, List<String>>> pendingCheckpointsIt =
+						bucketState.pendingFilesPerCheckpoint.entrySet().iterator();
+
+					while (pendingCheckpointsIt.hasNext()) {
+
+						Map.Entry<Long, List<String>> entry = pendingCheckpointsIt.next();
+						Long pastCheckpointId = entry.getKey();
+						List<String> pendingPaths = entry.getValue();
+
+						if (pastCheckpointId <= checkpointId) {
+							LOG.debug("Moving pending files to final location for checkpoint {}", pastCheckpointId);
+
+							for (String filename : pendingPaths) {
+								Path finalPath = new Path(filename);
+								Path pendingPath = getPendingPathFor(finalPath);
+
+								fs.rename(pendingPath, finalPath);
+								LOG.debug(
+									"Moving pending file {} to final location having completed checkpoint {}.",
+									pendingPath,
+									pastCheckpointId);
+							}
+							pendingCheckpointsIt.remove();
+						}
+					}
+
+					if (!bucketState.isWriterOpen &&
+						bucketState.pendingFiles.isEmpty() &&
+						bucketState.pendingFilesPerCheckpoint.isEmpty()) {
+
+						// We've dealt with all the pending files and the writer for this bucket is not currently open.
+						// Therefore this bucket is currently inactive and we can remove it from our state.
+						bucketStatesIt.remove();
+					}
+				}
+			}
+		}
+	}
+
+	@Override
+	public void snapshotState(FunctionSnapshotContext context) throws Exception {
+		Preconditions.checkNotNull(restoredBucketStates, "The operator has not been properly initialized.");
+
+		restoredBucketStates.clear();
+
+		synchronized (state.bucketStates) {
+			int subtaskIdx = getRuntimeContext().getIndexOfThisSubtask();
+
+			for (Map.Entry<String, BucketState<T>> bucketStateEntry : state.bucketStates.entrySet()) {
+				BucketState<T> bucketState = bucketStateEntry.getValue();
+
+				if (bucketState.isWriterOpen) {
+					bucketState.currentFileValidLength = bucketState.writer.flush();
+				}
+
+				synchronized (bucketState.pendingFilesPerCheckpoint) {
+					bucketState.pendingFilesPerCheckpoint.put(context.getCheckpointId(), bucketState.pendingFiles);
+				}
+				bucketState.pendingFiles = new ArrayList<>();
+			}
+			restoredBucketStates.add(state);
+
+			if (LOG.isDebugEnabled()) {
+				LOG.debug("{} idx {} checkpointed {}.", getClass().getSimpleName(), subtaskIdx, state);
+			}
+		}
+	}
+
+	private void handleRestoredBucketState(State<T> restoredState) {
+		Preconditions.checkNotNull(restoredState);
+
+		for (BucketState<T> bucketState : restoredState.bucketStates.values()) {
+
+			// we can clean all the pending files since they were renamed to
+			// final files after this checkpoint was successful
+			// (we re-start from the last **successful** checkpoint)
+			bucketState.pendingFiles.clear();
+
+			if (bucketState.currentFile != null) {
+
+				// We were writing to a file when the last checkpoint occurred. This file can either
+				// be still in-progress or became a pending file at some point after the checkpoint.
+				// Either way, we have to truncate it back to a valid state (or write a .valid-length
+				// file that specifies up to which length it is valid) and rename it to the final name
+				// before starting a new bucket file.
+
+				Path partPath = new Path(bucketState.currentFile);
+				try {
+					Path partPendingPath = getPendingPathFor(partPath);
+					Path partInProgressPath = getInProgressPathFor(partPath);
+
+					if (fs.exists(partPendingPath)) {
+						LOG.debug("In-progress file {} has been moved to pending after checkpoint, moving to final location.", partPath);
+						// has been moved to pending in the mean time, rename to final location
+						fs.rename(partPendingPath, partPath);
+					} else if (fs.exists(partInProgressPath)) {
+						LOG.debug("In-progress file {} is still in-progress, moving to final location.", partPath);
+						// it was still in progress, rename to final path
+						fs.rename(partInProgressPath, partPath);
+					} else if (fs.exists(partPath)) {
+						LOG.debug("In-Progress file {} was already moved to final location {}.", bucketState.currentFile, partPath);
+					} else {
+						LOG.debug("In-Progress file {} was neither moved to pending nor is still in progress. Possibly, " +
+							"it was moved to final location by a previous snapshot restore", bucketState.currentFile);
+					}
+
+					// We use reflection to get the .truncate() method, this
+					// is only available starting with Hadoop 2.7
+					if (this.refTruncate == null) {
+						this.refTruncate = reflectTruncate(fs);
+					}
+
+					// truncate it or write a ".valid-length" file to specify up to which point it is valid
+					if (refTruncate != null) {
+						LOG.debug("Truncating {} to valid length {}", partPath, bucketState.currentFileValidLength);
+						// some-one else might still hold the lease from a previous try, we are
+						// recovering, after all ...
+						if (fs instanceof DistributedFileSystem) {
+							DistributedFileSystem dfs = (DistributedFileSystem) fs;
+							LOG.debug("Trying to recover file lease {}", partPath);
+							dfs.recoverLease(partPath);
+							boolean isclosed = dfs.isFileClosed(partPath);
+							StopWatch sw = new StopWatch();
+							sw.start();
+							while (!isclosed) {
+								if (sw.getTime() > asyncTimeout) {
+									break;
+								}
+								try {
+									Thread.sleep(500);
+								} catch (InterruptedException e1) {
+									// ignore it
+								}
+								isclosed = dfs.isFileClosed(partPath);
+							}
+						}
+						Boolean truncated = (Boolean) refTruncate.invoke(fs, partPath, bucketState.currentFileValidLength);
+						if (!truncated) {
+							LOG.debug("Truncate did not immediately complete for {}, waiting...", partPath);
+
+							// we must wait for the asynchronous truncate operation to complete
+							StopWatch sw = new StopWatch();
+							sw.start();
+							long newLen = fs.getFileStatus(partPath).getLen();
+							while (newLen != bucketState.currentFileValidLength) {
+								if (sw.getTime() > asyncTimeout) {
+									break;
+								}
+								try {
+									Thread.sleep(500);
+								} catch (InterruptedException e1) {
+									// ignore it
+								}
+								newLen = fs.getFileStatus(partPath).getLen();
+							}
+							if (newLen != bucketState.currentFileValidLength) {
+								throw new RuntimeException("Truncate did not truncate to right length. Should be " + bucketState.currentFileValidLength + " is " + newLen + ".");
+							}
+						}
+					} else {
+						LOG.debug("Writing valid-length file for {} to specify valid length {}", partPath, bucketState.currentFileValidLength);
+						Path validLengthFilePath = getValidLengthPathFor(partPath);
+						if (!fs.exists(validLengthFilePath)) {
+							FSDataOutputStream lengthFileOut = fs.create(validLengthFilePath);
+							lengthFileOut.writeUTF(Long.toString(bucketState.currentFileValidLength));
+							lengthFileOut.close();
+						}
+					}
+
+					// Now that we've restored the bucket to a valid state, reset the current file info
+					bucketState.currentFile = null;
+					bucketState.currentFileValidLength = -1;
+					bucketState.isWriterOpen = false;
+				} catch (IOException e) {
+					LOG.error("Error while restoring BucketingSink state.", e);
+					throw new RuntimeException("Error while restoring BucketingSink state.", e);
+				} catch (InvocationTargetException | IllegalAccessException e) {
+					LOG.error("Could not invoke truncate.", e);
+					throw new RuntimeException("Could not invoke truncate.", e);
+				}
+			}
+
+			// Move files that are confirmed by a checkpoint but did not get moved to final location
+			// because the checkpoint notification did not happen before a failure
+
+			LOG.debug("Moving pending files to final location on restore.");
+
+			Set<Long> pastCheckpointIds = bucketState.pendingFilesPerCheckpoint.keySet();
+			for (Long pastCheckpointId : pastCheckpointIds) {
+				// All the pending files are buckets that have been completed but are waiting to be renamed
+				// to their final name
+				for (String filename : bucketState.pendingFilesPerCheckpoint.get(pastCheckpointId)) {
+					Path finalPath = new Path(filename);
+					Path pendingPath = getPendingPathFor(finalPath);
+
+					try {
+						if (fs.exists(pendingPath)) {
+							LOG.debug("Restoring BucketingSink State: Moving pending file {} to final location after complete checkpoint {}.", pendingPath, pastCheckpointId);
+							fs.rename(pendingPath, finalPath);
+						}
+					} catch (IOException e) {
+						LOG.error("Restoring BucketingSink State: Error while renaming pending file {} to final path {}: {}", pendingPath, finalPath, e);
+						throw new RuntimeException("Error while renaming pending file " + pendingPath + " to final path " + finalPath, e);
+					}
+				}
+			}
+
+			synchronized (bucketState.pendingFilesPerCheckpoint) {
+				bucketState.pendingFilesPerCheckpoint.clear();
+			}
+		}
+	}
+
+	// --------------------------------------------------------------------------------------------
+	//  Setters for User configuration values
+	// --------------------------------------------------------------------------------------------
+
+	/**
+	 * Sets the maximum bucket size in bytes.
+	 *
+	 * <p>
+	 * When a bucket part file becomes larger than this size a new bucket part file is started and
+	 * the old one is closed. The name of the bucket files depends on the {@link Bucketer}.
+	 *
+	 * @param batchSize The bucket part file size in bytes.
+	 */
+	public BucketingSink<T> setBatchSize(long batchSize) {
+		this.batchSize = batchSize;
+		return this;
+	}
+
+	/**
+	 * Sets the default time between checks for inactive buckets.
+	 *
+	 * @param interval The timeout, in milliseconds.
+	 */
+	public BucketingSink<T> setInactiveBucketCheckInterval(long interval) {
+		this.inactiveBucketCheckInterval = interval;
+		return this;
+	}
+
+	/**
+	 * Sets the default threshold for marking a bucket as inactive and closing its part files.
+	 * Buckets which haven't been written to for at least this period of time become inactive.
+	 *
+	 * @param threshold The timeout, in milliseconds.
+	 */
+	public BucketingSink<T> setInactiveBucketThreshold(long threshold) {
+		this.inactiveBucketThreshold = threshold;
+		return this;
+	}
+
+	/**
+	 * Sets the {@link Bucketer} to use for determining the bucket files to write to.
+	 *
+	 * @param bucketer The bucketer to use.
+	 */
+	public BucketingSink<T> setBucketer(Bucketer<T> bucketer) {
+		this.bucketer = bucketer;
+		return this;
+	}
+
+	/**
+	 * Sets the {@link Writer} to be used for writing the incoming elements to bucket files.
+	 *
+	 * @param writer The {@code Writer} to use.
+	 */
+	public BucketingSink<T> setWriter(Writer<T> writer) {
+		this.writerTemplate = writer;
+		return this;
+	}
+
+	/**
+	 * Sets the suffix of in-progress part files. The default is {@code "in-progress"}.
+	 */
+	public BucketingSink<T> setInProgressSuffix(String inProgressSuffix) {
+		this.inProgressSuffix = inProgressSuffix;
+		return this;
+	}
+
+	/**
+	 * Sets the prefix of in-progress part files. The default is {@code "_"}.
+	 */
+	public BucketingSink<T> setInProgressPrefix(String inProgressPrefix) {
+		this.inProgressPrefix = inProgressPrefix;
+		return this;
+	}
+
+	/**
+	 * Sets the suffix of pending part files. The default is {@code ".pending"}.
+	 */
+	public BucketingSink<T> setPendingSuffix(String pendingSuffix) {
+		this.pendingSuffix = pendingSuffix;
+		return this;
+	}
+
+	/**
+	 * Sets the prefix of pending part files. The default is {@code "_"}.
+	 */
+	public BucketingSink<T> setPendingPrefix(String pendingPrefix) {
+		this.pendingPrefix = pendingPrefix;
+		return this;
+	}
+
+	/**
+	 * Sets the suffix of valid-length files. The default is {@code ".valid-length"}.
+	 */
+	public BucketingSink<T> setValidLengthSuffix(String validLengthSuffix) {
+		this.validLengthSuffix = validLengthSuffix;
+		return this;
+	}
+
+	/**
+	 * Sets the prefix of valid-length files. The default is {@code "_"}.
+	 */
+	public BucketingSink<T> setValidLengthPrefix(String validLengthPrefix) {
+		this.validLengthPrefix = validLengthPrefix;
+		return this;
+	}
+
+	/**
+	 * Sets the prefix of part files.  The default is {@code "part"}.
+	 */
+	public BucketingSink<T> setPartPrefix(String partPrefix) {
+		this.partPrefix = partPrefix;
+		return this;
+	}
+
+	/**
+	 * Disable cleanup of leftover in-progress/pending files when the sink is opened.
+	 *
+	 * <p>
+	 * This should only be disabled if using the sink without checkpoints, to not remove
+	 * the files already in the directory.
+	 *
+	 * @deprecated This option is deprecated and remains only for backwards compatibility.
+	 * We do not clean up lingering files anymore.
+	 */
+	@Deprecated
+	public BucketingSink<T> disableCleanupOnOpen() {
+		return this;
+	}
+
+	/**
+	 * Sets the default timeout for asynchronous operations such as recoverLease and truncate.
+	 *
+	 * @param timeout The timeout, in milliseconds.
+	 */
+	public BucketingSink<T> setAsyncTimeout(long timeout) {
+		this.asyncTimeout = timeout;
+		return this;
+	}
+
+	// --------------------------------------------------------------------------------------------
+	//  Internal Classes
+	// --------------------------------------------------------------------------------------------
+
+	/**
+	 * This is used during snapshot/restore to keep track of in-progress buckets.
+	 * For each bucket, we maintain a state.
+	 */
+	static final class State<T> implements Serializable {
+		private static final long serialVersionUID = 1L;
+
+		/**
+		 * For every bucket directory (key), we maintain a bucket state (value).
+		 */
+		final Map<String, BucketState<T>> bucketStates = new HashMap<>();
+
+		void addBucketState(Path bucketPath, BucketState<T> state) {
+			synchronized (bucketStates) {
+				bucketStates.put(bucketPath.toString(), state);
+			}
+		}
+
+		BucketState<T> getBucketState(Path bucketPath) {
+			synchronized (bucketStates) {
+				return bucketStates.get(bucketPath.toString());
+			}
+		}
+
+		@Override
+		public String toString() {
+			return bucketStates.toString();
+		}
+	}
+
+	/**
+	 * This is used for keeping track of the current in-progress buckets and files that we mark
+	 * for moving from pending to final location after we get a checkpoint-complete notification.
+	 */
+	static final class BucketState<T> implements Serializable {
+		private static final long serialVersionUID = 1L;
+
+		/**
+		 * The file that was in-progress when the last checkpoint occurred.
+		 */
+		String currentFile;
+
+		/**
+		 * The valid length of the in-progress file at the time of the last checkpoint.
+		 */
+		long currentFileValidLength = -1;
+
+		/**
+		 * The time this bucket was last written to.
+		 */
+		long lastWrittenToTime;
+
+		/**
+		 * Pending files that accumulated since the last checkpoint.
+		 */
+		List<String> pendingFiles = new ArrayList<>();
+
+		/**
+		 * When doing a checkpoint we move the pending files since the last checkpoint to this map
+		 * with the id of the checkpoint. When we get the checkpoint-complete notification we move
+		 * pending files of completed checkpoints to their final location.
+		 */
+		final Map<Long, List<String>> pendingFilesPerCheckpoint = new HashMap<>();
+
+		/**
+		 * For counting the part files inside a bucket directory. Part files follow the pattern
+		 * {@code "{part-prefix}-{subtask}-{count}"}. When creating new part files we increase the counter.
+		 */
+		private transient int partCounter;
+
+		/**
+		 * Tracks if the writer is currently opened or closed.
+		 */
+		private transient boolean isWriterOpen;
+
+		/**
+		 * The actual writer that we user for writing the part files.
+		 */
+		private transient Writer<T> writer;
+
+		@Override
+		public String toString() {
+			return
+				"In-progress=" + currentFile +
+					" validLength=" + currentFileValidLength +
+					" pendingForNextCheckpoint=" + pendingFiles +
+					" pendingForPrevCheckpoints=" + pendingFilesPerCheckpoint +
+					" lastModified@" + lastWrittenToTime;
+		}
+
+		BucketState(long lastWrittenToTime) {
+			this.lastWrittenToTime = lastWrittenToTime;
+		}
+	}
+}

http://git-wip-us.apache.org/repos/asf/flink/blob/de4fe3b7/flink-connectors/flink-connector-filesystem/src/main/java/org/apache/flink/streaming/connectors/fs/bucketing/DateTimeBucketer.java
----------------------------------------------------------------------
diff --git a/flink-connectors/flink-connector-filesystem/src/main/java/org/apache/flink/streaming/connectors/fs/bucketing/DateTimeBucketer.java b/flink-connectors/flink-connector-filesystem/src/main/java/org/apache/flink/streaming/connectors/fs/bucketing/DateTimeBucketer.java
new file mode 100644
index 0000000..b985e14
--- /dev/null
+++ b/flink-connectors/flink-connector-filesystem/src/main/java/org/apache/flink/streaming/connectors/fs/bucketing/DateTimeBucketer.java
@@ -0,0 +1,102 @@
+/*
+ * 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.streaming.connectors.fs.bucketing;
+
+import org.apache.flink.streaming.connectors.fs.Clock;
+import org.apache.hadoop.fs.Path;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+/**
+ * A {@link Bucketer} that assigns to buckets based on current system time.
+ *
+ * <p>
+ * The {@code DateTimeBucketer} will create directories of the following form:
+ * {@code /{basePath}/{dateTimePath}/}. The {@code basePath} is the path
+ * that was specified as a base path when creating the
+ * {@link BucketingSink}. The {@code dateTimePath}
+ * is determined based on the current system time and the user provided format string.
+ *
+ * <p>
+ * {@link SimpleDateFormat} is used to derive a date string from the current system time and
+ * the date format string. The default format string is {@code "yyyy-MM-dd--HH"} so the rolling
+ * files will have a granularity of hours.
+ *
+ *
+ * <p>
+ * Example:
+ *
+ * <pre>{@code
+ *     Bucketer buck = new DateTimeBucketer("yyyy-MM-dd--HH");
+ * }</pre>
+ *
+ * This will create for example the following bucket path:
+ * {@code /base/1976-12-31-14/}
+ *
+ */
+public class DateTimeBucketer<T> implements Bucketer<T> {
+
+	private static final long serialVersionUID = 1L;
+
+	private static final String DEFAULT_FORMAT_STRING = "yyyy-MM-dd--HH";
+
+	private final String formatString;
+
+	private transient SimpleDateFormat dateFormatter;
+
+	/**
+	 * Creates a new {@code DateTimeBucketer} with format string {@code "yyyy-MM-dd--HH"}.
+	 */
+	public DateTimeBucketer() {
+		this(DEFAULT_FORMAT_STRING);
+	}
+
+	/**
+	 * Creates a new {@code DateTimeBucketer} with the given date/time format string.
+	 *
+	 * @param formatString The format string that will be given to {@code SimpleDateFormat} to determine
+	 *                     the bucket path.
+	 */
+	public DateTimeBucketer(String formatString) {
+		this.formatString = formatString;
+
+		this.dateFormatter = new SimpleDateFormat(formatString);
+	}
+
+	private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
+		in.defaultReadObject();
+
+		this.dateFormatter = new SimpleDateFormat(formatString);
+	}
+
+	@Override
+	public Path getBucketPath(Clock clock, Path basePath, T element) {
+		String newDateTimeString = dateFormatter.format(new Date(clock.currentTimeMillis()));
+		return new Path(basePath + "/" + newDateTimeString);
+	}
+
+	@Override
+	public String toString() {
+		return "DateTimeBucketer{" +
+				"formatString='" + formatString + '\'' +
+				'}';
+	}
+}

http://git-wip-us.apache.org/repos/asf/flink/blob/de4fe3b7/flink-connectors/flink-connector-filesystem/src/main/resources/log4j.properties
----------------------------------------------------------------------
diff --git a/flink-connectors/flink-connector-filesystem/src/main/resources/log4j.properties b/flink-connectors/flink-connector-filesystem/src/main/resources/log4j.properties
new file mode 100644
index 0000000..fe60d94
--- /dev/null
+++ b/flink-connectors/flink-connector-filesystem/src/main/resources/log4j.properties
@@ -0,0 +1,27 @@
+################################################################################
+#  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.
+################################################################################
+
+log4j.rootLogger=OFF, testlogger
+
+log4j.appender.testlogger=org.apache.log4j.ConsoleAppender
+log4j.appender.testlogger.target = System.err
+log4j.appender.testlogger.layout=org.apache.log4j.PatternLayout
+log4j.appender.testlogger.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n
+
+# suppress the irrelevant (wrong) warnings from the netty channel handler
+log4j.logger.org.jboss.netty.channel.DefaultChannelPipeline=ERROR, testlogger

http://git-wip-us.apache.org/repos/asf/flink/blob/de4fe3b7/flink-connectors/flink-connector-filesystem/src/test/java/org/apache/flink/streaming/connectors/fs/RollingSinkFaultToleranceITCase.java
----------------------------------------------------------------------
diff --git a/flink-connectors/flink-connector-filesystem/src/test/java/org/apache/flink/streaming/connectors/fs/RollingSinkFaultToleranceITCase.java b/flink-connectors/flink-connector-filesystem/src/test/java/org/apache/flink/streaming/connectors/fs/RollingSinkFaultToleranceITCase.java
new file mode 100644
index 0000000..36c0d03
--- /dev/null
+++ b/flink-connectors/flink-connector-filesystem/src/test/java/org/apache/flink/streaming/connectors/fs/RollingSinkFaultToleranceITCase.java
@@ -0,0 +1,300 @@
+/*
+ * 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.streaming.connectors.fs;
+
+import com.google.common.collect.Sets;
+import org.apache.flink.api.common.functions.RichMapFunction;
+import org.apache.flink.streaming.api.checkpoint.CheckpointedAsynchronously;
+import org.apache.flink.streaming.api.datastream.DataStream;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.source.RichParallelSourceFunction;
+import org.apache.flink.test.checkpointing.StreamFaultToleranceTestBase;
+import org.apache.flink.util.NetUtils;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.LocatedFileStatus;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.RemoteIterator;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.ClassRule;
+import org.junit.rules.TemporaryFolder;
+
+import java.io.BufferedReader;
+import java.io.ByteArrayInputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Tests for {@link org.apache.flink.streaming.connectors.fs.RollingSink}.
+ *
+ * <p>
+ * This test only verifies the exactly once behaviour of the sink. Another test tests the
+ * rolling behaviour.
+ *
+ * @deprecated should be removed with the {@link RollingSink}.
+ */
+@Deprecated
+public class RollingSinkFaultToleranceITCase extends StreamFaultToleranceTestBase {
+
+	final long NUM_STRINGS = 16_000;
+
+	@ClassRule
+	public static TemporaryFolder tempFolder = new TemporaryFolder();
+
+	private static MiniDFSCluster hdfsCluster;
+	private static org.apache.hadoop.fs.FileSystem dfs;
+
+	private static String outPath;
+
+	private static final String PENDING_SUFFIX = ".pending";
+	private static final String IN_PROGRESS_SUFFIX = ".in-progress";
+
+	@BeforeClass
+	public static void createHDFS() throws IOException {
+		Configuration conf = new Configuration();
+
+		File dataDir = tempFolder.newFolder();
+
+		conf.set(MiniDFSCluster.HDFS_MINIDFS_BASEDIR, dataDir.getAbsolutePath());
+		MiniDFSCluster.Builder builder = new MiniDFSCluster.Builder(conf);
+		hdfsCluster = builder.build();
+
+		dfs = hdfsCluster.getFileSystem();
+
+		outPath = "hdfs://"
+				+ NetUtils.hostAndPortToUrlString(hdfsCluster.getURI().getHost(), hdfsCluster.getNameNodePort())
+				+ "/string-non-rolling-out";
+	}
+
+	@AfterClass
+	public static void destroyHDFS() {
+		if (hdfsCluster != null) {
+			hdfsCluster.shutdown();
+		}
+	}
+
+	@Override
+	public void testProgram(StreamExecutionEnvironment env) {
+		assertTrue("Broken test setup", NUM_STRINGS % 40 == 0);
+
+		int PARALLELISM = 12;
+
+		env.enableCheckpointing(20);
+		env.setParallelism(PARALLELISM);
+		env.disableOperatorChaining();
+
+		DataStream<String> stream = env.addSource(new StringGeneratingSourceFunction(NUM_STRINGS)).startNewChain();
+
+		DataStream<String> mapped = stream
+				.map(new OnceFailingIdentityMapper(NUM_STRINGS));
+
+		RollingSink<String> sink = new RollingSink<String>(outPath)
+				.setBucketer(new NonRollingBucketer())
+				.setBatchSize(10000)
+				.setValidLengthPrefix("")
+				.setPendingPrefix("")
+				.setPendingSuffix(PENDING_SUFFIX)
+				.setInProgressSuffix(IN_PROGRESS_SUFFIX);
+
+		mapped.addSink(sink);
+
+	}
+
+	@Override
+	public void postSubmit() throws Exception {
+		// We read the files and verify that we have read all the strings. If a valid-length
+		// file exists we only read the file to that point. (This test should work with
+		// FileSystems that support truncate() and with others as well.)
+
+		Pattern messageRegex = Pattern.compile("message (\\d*)");
+
+		// Keep a set of the message IDs that we read. The size must equal the read count and
+		// the NUM_STRINGS. If numRead is bigger than the size of the set we have seen some
+		// elements twice.
+		Set<Integer> readNumbers = Sets.newHashSet();
+
+		HashSet<String> uniqMessagesRead = new HashSet<>();
+		HashSet<String> messagesInCommittedFiles = new HashSet<>();
+
+		RemoteIterator<LocatedFileStatus> files = dfs.listFiles(new Path(
+				outPath), true);
+
+		while (files.hasNext()) {
+			LocatedFileStatus file = files.next();
+
+			if (!file.getPath().toString().endsWith(".valid-length")) {
+				int validLength = (int) file.getLen();
+				if (dfs.exists(file.getPath().suffix(".valid-length"))) {
+					FSDataInputStream inStream = dfs.open(file.getPath().suffix(".valid-length"));
+					String validLengthString = inStream.readUTF();
+					validLength = Integer.parseInt(validLengthString);
+					System.out.println("VALID LENGTH: " + validLength);
+				}
+				FSDataInputStream inStream = dfs.open(file.getPath());
+				byte[] buffer = new byte[validLength];
+				inStream.readFully(0, buffer, 0, validLength);
+				inStream.close();
+
+				ByteArrayInputStream bais = new ByteArrayInputStream(buffer);
+
+				InputStreamReader inStreamReader = new InputStreamReader(bais);
+				BufferedReader br = new BufferedReader(inStreamReader);
+
+				String line = br.readLine();
+				while (line != null) {
+					Matcher matcher = messageRegex.matcher(line);
+					if (matcher.matches()) {
+						uniqMessagesRead.add(line);
+
+						// check that in the committed files there are no duplicates
+						if (!file.getPath().toString().endsWith(IN_PROGRESS_SUFFIX) && !file.getPath().toString().endsWith(PENDING_SUFFIX)) {
+							if (!messagesInCommittedFiles.add(line)) {
+								Assert.fail("Duplicate entry in committed bucket.");
+							}
+						}
+
+						int messageId = Integer.parseInt(matcher.group(1));
+						readNumbers.add(messageId);
+					} else {
+						Assert.fail("Read line does not match expected pattern.");
+					}
+					line = br.readLine();
+				}
+				br.close();
+				inStreamReader.close();
+				bais.close();
+			}
+		}
+
+		// Verify that we read all strings (at-least-once)
+		Assert.assertEquals(NUM_STRINGS, readNumbers.size());
+
+		// Verify that we don't have duplicates (boom!, exactly-once)
+		Assert.assertEquals(NUM_STRINGS, uniqMessagesRead.size());
+	}
+
+	private static class OnceFailingIdentityMapper extends RichMapFunction<String, String> {
+		private static final long serialVersionUID = 1L;
+
+		private static volatile boolean hasFailed = false;
+
+		private final long numElements;
+
+		private long failurePos;
+		private long count;
+
+
+		OnceFailingIdentityMapper(long numElements) {
+			this.numElements = numElements;
+		}
+
+		@Override
+		public void open(org.apache.flink.configuration.Configuration parameters) throws IOException {
+			long failurePosMin = (long) (0.7 * numElements / getRuntimeContext().getNumberOfParallelSubtasks());
+			long failurePosMax = (long) (0.9 * numElements / getRuntimeContext().getNumberOfParallelSubtasks());
+
+			failurePos = (new Random().nextLong() % (failurePosMax - failurePosMin)) + failurePosMin;
+			count = 0;
+		}
+
+		@Override
+		public String map(String value) throws Exception {
+			count++;
+			if (!hasFailed && count >= failurePos) {
+				hasFailed = true;
+				throw new Exception("Test Failure");
+			}
+
+			return value;
+		}
+	}
+
+	private static class StringGeneratingSourceFunction extends RichParallelSourceFunction<String>
+			implements CheckpointedAsynchronously<Integer> {
+
+		private static final long serialVersionUID = 1L;
+
+		private final long numElements;
+
+		private int index;
+
+		private volatile boolean isRunning = true;
+
+
+		StringGeneratingSourceFunction(long numElements) {
+			this.numElements = numElements;
+		}
+
+		@Override
+		public void run(SourceContext<String> ctx) throws Exception {
+			final Object lockingObject = ctx.getCheckpointLock();
+
+			final int step = getRuntimeContext().getNumberOfParallelSubtasks();
+
+			if (index == 0) {
+				index = getRuntimeContext().getIndexOfThisSubtask();
+			}
+
+			while (isRunning && index < numElements) {
+
+				Thread.sleep(1);
+				synchronized (lockingObject) {
+					ctx.collect("message " + index);
+					index += step;
+				}
+			}
+		}
+
+		@Override
+		public void cancel() {
+			isRunning = false;
+		}
+
+		private static String randomString(StringBuilder bld, Random rnd) {
+			final int len = rnd.nextInt(10) + 5;
+
+			for (int i = 0; i < len; i++) {
+				char next = (char) (rnd.nextInt(20000) + 33);
+				bld.append(next);
+			}
+
+			return bld.toString();
+		}
+
+		@Override
+		public Integer snapshotState(long checkpointId, long checkpointTimestamp) {
+			return index;
+		}
+
+		@Override
+		public void restoreState(Integer state) {
+			index = state;
+		}
+	}
+}


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