Java tutorial
/* * 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 com.mvad.flink.demo.streaming.lib.sink.bucketing; import org.apache.commons.lang3.time.StopWatch; import org.apache.flink.api.common.ExecutionConfig; 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.streaming.api.checkpoint.Checkpointed; 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.operators.Triggerable; import org.apache.hadoop.fs.*; 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.*; /** * Sink that emits its input elements to {@link 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. * These contain the actual written data. * * <p> * The sink uses a {@link Bucketer} to determine the bucket directories that elements 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 bucketer is a {@link DateTimeBucketer} * with date format string {@code ""yyyy-MM-dd--HH"}. You can specify a custom {@code Bucketer} * using {@link #setBucketer(Bucketer)}. For example, use * {@link BasePathBucketer} if you don't want to have buckets but still 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 {@code "part-1-17"}. 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 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 buckets being written to change over time. In these cases, the sink needs to * determine when a bucket has become inactive, in order to flush and close the part file. A bucket is * regarded inactive if it hasn't been written to recently. To support this there are two configurable * settings: the frequency to check for inactivity, configured by * {@link #setInactiveBucketCheckInterval(long)} and the minimum amount of time a bucket must not be * written to before it should be regarded inactive, configured by * {@link #setInactiveBucketThreshold(long)}. Both of these parameters default to {@code 60,000 ms}. * * <p> * Part files can be in one of three states: in-progress, pending or 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 in-progress. Once * a part file is closed for writing it becomes pending. When a checkpoint is successful the * currently pending files will be moved to finished. If a failure occurs the pending files * will be deleted to reset state to the last checkpoint. The data in in-progress files will * also have to be rolled back. If the {@code FileSystem} supports the {@code truncate} call * this will be used to reset the file back to a previous state. If not, a special file * with the same name as the part file and the suffix {@code ".valid-length"} will be written * 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, for example with * {@link #setPendingSuffix(String)}. * * <p> * Note: 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. * * <p> * The part files are written using an instance of {@link Writer}. By default * {@link StringWriter} is used, which writes the result * of {@code toString()} for every element. Separated by newlines. You can configure the writer * using {@link #setWriter(Writer)}. For example, * {@link SequenceFileWriter} can be used to write * Hadoop {@code SequenceFiles}. * * <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, Checkpointed<BucketingSink.State<T>>, CheckpointListener, Triggerable { 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. * * 6 times the default block size */ private final long DEFAULT_BATCH_SIZE = 1024L * 1024L * 384L; /** * The default time between checks for inactive buckets. */ private final long DEFAULT_INACTIVE_BUCKET_CHECK_INTERVAL_MS = 60 * 1000L; /** * 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. */ private final long DEFAULT_INACTIVE_BUCKET_THRESHOLD_MS = 60 * 1000L; /** * This is used for part files that we are writing to but which where not yet confirmed * by a checkpoint. */ private final String DEFAULT_IN_PROGRESS_SUFFIX = ".in-progress"; /** * See above, but for prefix */ private final String DEFAULT_IN_PROGRESS_PREFIX = "_"; /** * This is used for part files that we are not writing to but which are not yet confirmed by * checkpoint. */ private final String DEFAULT_PENDING_SUFFIX = ".pending"; /** * See above, but for prefix. */ private final String DEFAULT_PENDING_PREFIX = "_"; /** * When truncate() is not supported on the used FileSystem we instead write a * file along the part file with this ending that contains the length up to which * the part file is valid. */ private final String DEFAULT_VALID_SUFFIX = ".valid-length"; /** * See above, but for prefix. */ private final String DEFAULT_VALID_PREFIX = "_"; /** * The default prefix for part files. */ private final String DEFAULT_PART_REFIX = "part"; /** * The default suffix for part files. */ private final String DEFAULT_PART_SUFFIX = ""; /** * The default timeout for asynchronous operations such as recoverLease and truncate. In * milliseconds. */ 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; /** * If this is true we remove any leftover in-progress/pending files when the sink is opened. * * <p> * This should only be set to false if using the sink without checkpoints, to not remove * the files already in the directory. */ private boolean cleanupOnOpen = true; 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; private String partSuffix = DEFAULT_PART_SUFFIX; /** * The timeout for asynchronous operations such as recoverLease and truncate. In * milliseconds. */ private long asyncTimeout = DEFAULT_ASYNC_TIMEOUT_MS; // -------------------------------------------------------------------------------------------- // Internal fields (not configurable by user) // -------------------------------------------------------------------------------------------- /** * Our subtask index, retrieved from the {@code RuntimeContext} in {@link #open}. */ private transient int subtaskIndex; /** * 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. In there we store state for * every open bucket: the current part file path, the valid length of the in-progress files and * pending part files. */ private transient State<T> state; private transient org.apache.hadoop.conf.Configuration hadoopConf; private transient Clock clock; /** * Creates a new {@code BucketingSink} that writes files to the given base directory. * * <p> * This uses a{@link DateTimeBucketer} as 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<T>(); this.writerTemplate = new StringWriter<>(); } @Override @SuppressWarnings("unchecked") public void setInputType(TypeInformation<?> type, ExecutionConfig executionConfig) { if (this.writerTemplate instanceof InputTypeConfigurable) { ((InputTypeConfigurable) writerTemplate).setInputType(type, executionConfig); } } @Override public void open(Configuration parameters) throws Exception { super.open(parameters); subtaskIndex = getRuntimeContext().getIndexOfThisSubtask(); state = new State<T>(); Path baseDirectory = new Path(basePath); hadoopConf = HadoopFileSystem.getHadoopConfiguration(); FileSystem fs = baseDirectory.getFileSystem(hadoopConf); refTruncate = reflectTruncate(fs); long currentProcessingTime = ((StreamingRuntimeContext) getRuntimeContext()).getCurrentProcessingTime(); checkForInactiveBuckets(currentProcessingTime); ((StreamingRuntimeContext) getRuntimeContext()) .registerTimer(currentProcessingTime + inactiveBucketCheckInterval, this); this.clock = new Clock() { @Override public long currentTimeMillis() { return ((StreamingRuntimeContext) getRuntimeContext()).getCurrentProcessingTime(); } }; // delete pending/in-progress files that might be left if we fail while // no checkpoint has yet been done try { if (fs.exists(baseDirectory) && cleanupOnOpen) { RemoteIterator<LocatedFileStatus> bucketFiles = fs.listFiles(baseDirectory, true); while (bucketFiles.hasNext()) { LocatedFileStatus file = bucketFiles.next(); if (file.getPath().toString().endsWith(pendingSuffix)) { // only delete files that contain our subtask index if (file.getPath().toString().contains(partPrefix + "-" + subtaskIndex + "-")) { LOG.debug("(OPEN) Deleting leftover pending file {}", file.getPath().toString()); fs.delete(file.getPath(), true); } } if (file.getPath().toString().endsWith(inProgressSuffix)) { // only delete files that contain our subtask index if (file.getPath().toString().contains(partPrefix + "-" + subtaskIndex + "-")) { LOG.debug("(OPEN) Deleting leftover in-progress file {}", file.getPath().toString()); fs.delete(file.getPath(), true); } } } } } catch (IOException e) { LOG.error("Error while deleting leftover pending/in-progress files: {}", e); throw new RuntimeException("Error while deleting leftover pending/in-progress files.", e); } } @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 = ((StreamingRuntimeContext) getRuntimeContext()).getCurrentProcessingTime(); if (!state.hasBucketState(bucketPath)) { state.addBucketState(bucketPath, new BucketState<T>(currentProcessingTime)); } BucketState<T> bucketState = state.getBucketState(bucketPath); if (shouldRoll(bucketState)) { openNewPartFile(bucketPath, bucketState); } bucketState.writer.write(value); bucketState.lastWrittenToTime = currentProcessingTime; } /** * Determines whether we should change the file we are writing to within a given bucket. * * <p> * This will roll if no file was created yet or if the file size is larger than the specified size. */ private boolean shouldRoll(BucketState<T> bucketState) throws IOException { boolean shouldRoll = false; 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 trigger(long timestamp) throws Exception { long currentProcessingTime = ((StreamingRuntimeContext) getRuntimeContext()).getCurrentProcessingTime(); checkForInactiveBuckets(currentProcessingTime); ((StreamingRuntimeContext) getRuntimeContext()) .registerTimer(currentProcessingTime + inactiveBucketCheckInterval, this); } /** * Checks for inactive buckets, and closes them. This enables in-progress files to be moved to * the pending state and 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.", subtaskIndex, inactiveBucketThreshold); closeCurrentPartFile(entry.getValue()); } } } } /** * Opens a new part file. * * <p> * This closes the old bucket file and retrieves a new bucket path from the {@code Bucketer}. */ private void openNewPartFile(Path bucketPath, BucketState<T> bucketState) throws Exception { closeCurrentPartFile(bucketState); FileSystem fs = new Path(basePath).getFileSystem(hadoopConf); 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); } } Path partPath = new Path(bucketPath, partPrefix + "-" + subtaskIndex + "-" + bucketState.partCounter + partSuffix); // This should work since there is only one parallel subtask that tries names with // our subtask id. Otherwise we would run into concurrency issues here. while (fs.exists(partPath) || fs .exists(new Path(partPath.getParent(), pendingPrefix + partPath.getName()).suffix(pendingSuffix))) { bucketState.partCounter++; partPath = new Path(bucketPath, partPrefix + "-" + subtaskIndex + "-" + bucketState.partCounter + partSuffix); } // 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 = new Path(partPath.getParent(), inProgressPrefix + partPath.getName()) .suffix(inProgressSuffix); // If we don't already have a writer for this bucket, create one if (bucketState.writer == null) { bucketState.writer = writerTemplate.duplicate(); } bucketState.writer.open(fs, inProgressPath); bucketState.isWriterOpen = true; } /** * Closes the current part file. * * <p> * This moves the current in-progress part file to a pending file and adds it to the list * of pending files in our bucket 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 = new Path(currentPartPath.getParent(), inProgressPrefix + currentPartPath.getName()).suffix(inProgressSuffix); Path pendingPath = new Path(currentPartPath.getParent(), pendingPrefix + currentPartPath.getName()) .suffix(pendingSuffix); FileSystem fs = inProgressPath.getFileSystem(hadoopConf); 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> * Note: 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; } @Override public void notifyCheckpointComplete(long checkpointId) throws Exception { synchronized (state.bucketStates) { Iterator<Map.Entry<String, BucketState<T>>> it = state.bucketStates.entrySet().iterator(); while (it.hasNext()) { BucketState<T> bucketState = it.next().getValue(); synchronized (bucketState.pendingFilesPerCheckpoint) { Set<Long> pastCheckpointIds = bucketState.pendingFilesPerCheckpoint.keySet(); Set<Long> checkpointsToRemove = new HashSet<>(); for (Long pastCheckpointId : pastCheckpointIds) { if (pastCheckpointId <= checkpointId) { LOG.debug("Moving pending files to final location for checkpoint {}", pastCheckpointId); // 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 = new Path(finalPath.getParent(), pendingPrefix + finalPath.getName()).suffix(pendingSuffix); FileSystem fs = pendingPath.getFileSystem(hadoopConf); fs.rename(pendingPath, finalPath); LOG.debug( "Moving pending file {} to final location having completed checkpoint {}.", pendingPath, pastCheckpointId); } checkpointsToRemove.add(pastCheckpointId); } } if (!bucketState.isWriterOpen && bucketState.pendingFiles.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. it.remove(); } else { for (Long toRemove : checkpointsToRemove) { bucketState.pendingFilesPerCheckpoint.remove(toRemove); } } } } } } @Override public State<T> snapshotState(long checkpointId, long checkpointTimestamp) throws Exception { synchronized (state.bucketStates) { for (BucketState<T> bucketState : state.bucketStates.values()) { if (bucketState.isWriterOpen) { long pos = bucketState.writer.flush(); bucketState.currentFileValidLength = pos; } synchronized (bucketState.pendingFilesPerCheckpoint) { bucketState.pendingFilesPerCheckpoint.put(checkpointId, bucketState.pendingFiles); } bucketState.pendingFiles = new ArrayList<>(); } } return state; } @Override public void restoreState(State<T> state) { this.state = state; FileSystem fs; try { fs = new Path(basePath).getFileSystem(HadoopFileSystem.getHadoopConfiguration()); } catch (IOException e) { LOG.error("Error while creating FileSystem in checkpoint restore.", e); throw new RuntimeException("Error while creating FileSystem in checkpoint restore.", e); } for (BucketState<T> bucketState : state.bucketStates.values()) { // we can clean all the pending files since they where renamed to final files // after this checkpoint was successful bucketState.pendingFiles.clear(); if (bucketState.currentFile != null) { // We were writing to a file when the last checkpoint occured. 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 = new Path(partPath.getParent(), pendingPrefix + partPath.getName()) .suffix(pendingSuffix); Path partInProgressPath = new Path(partPath.getParent(), inProgressPrefix + partPath.getName()) .suffix(inProgressSuffix); 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); } 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 = new Path(partPath.getParent(), validLengthPrefix + partPath.getName()).suffix(validLengthSuffix); 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; } 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("Cound not invoke truncate.", e); throw new RuntimeException("Could not invoke truncate.", e); } } LOG.debug("Clearing pending/in-progress files."); // 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 Set<Long> pastCheckpointIds = bucketState.pendingFilesPerCheckpoint.keySet(); LOG.debug("Moving pending files to final location on restore."); 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 = new Path(finalPath.getParent(), pendingPrefix + finalPath.getName()) .suffix(pendingSuffix); try { if (fs.exists(pendingPath)) { LOG.debug( "(RESTORE) Moving pending file {} to final location after complete checkpoint {}.", pendingPath, pastCheckpointId); fs.rename(pendingPath, finalPath); } } catch (IOException e) { LOG.error("(RESTORE) 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(); } } // we need to get this here since open() has not yet been called int subtaskIndex = getRuntimeContext().getIndexOfThisSubtask(); // delete pending files try { RemoteIterator<LocatedFileStatus> bucketFiles = fs.listFiles(new Path(basePath), true); while (bucketFiles.hasNext()) { LocatedFileStatus file = bucketFiles.next(); if (file.getPath().toString().endsWith(pendingSuffix)) { // only delete files that contain our subtask index if (file.getPath().toString().contains(partPrefix + "-" + subtaskIndex + "-")) { LOG.debug("(RESTORE) Deleting pending file {}", file.getPath().toString()); fs.delete(file.getPath(), true); } } if (file.getPath().toString().endsWith(inProgressSuffix)) { // only delete files that contain our subtask index if (file.getPath().toString().contains(partPrefix + "-" + subtaskIndex + "-")) { LOG.debug("(RESTORE) Deleting in-progress file {}", file.getPath().toString()); fs.delete(file.getPath(), true); } } } } catch (IOException e) { LOG.error("Error while deleting old pending files: {}", e); throw new RuntimeException("Error while deleting old pending files.", e); } } // -------------------------------------------------------------------------------------------- // 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; } /** * Sets the suffix of part files. The default is empty. */ public BucketingSink<T> setPartSuffix(String partSuffix) { this.partSuffix = partSuffix; 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. */ public BucketingSink<T> disableCleanupOnOpen() { this.cleanupOnOpen = false; 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<>(); boolean hasBucketState(Path bucketPath) { synchronized (bucketStates) { return bucketStates.containsKey(bucketPath.toString()); } } 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()); } } } /** * 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 = null; /** * 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 = false; /** * The actual writer that we user for writing the part files. */ private transient Writer<T> writer; public BucketState(long lastWrittenToTime) { this.lastWrittenToTime = lastWrittenToTime; } } }