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 org.apache.accumulo.hadoopImpl.mapreduce; import static org.apache.accumulo.fate.util.UtilWaitThread.sleepUninterruptibly; import java.io.IOException; import java.net.InetAddress; import java.security.SecureRandom; import java.util.ArrayList; import java.util.Collection; import java.util.HashMap; import java.util.Iterator; import java.util.LinkedList; import java.util.List; import java.util.Map; import java.util.Random; import java.util.concurrent.TimeUnit; import org.apache.accumulo.core.client.AccumuloClient; import org.apache.accumulo.core.client.AccumuloException; import org.apache.accumulo.core.client.AccumuloSecurityException; import org.apache.accumulo.core.client.BatchScanner; import org.apache.accumulo.core.client.ClientSideIteratorScanner; import org.apache.accumulo.core.client.IsolatedScanner; import org.apache.accumulo.core.client.IteratorSetting; import org.apache.accumulo.core.client.Scanner; import org.apache.accumulo.core.client.ScannerBase; import org.apache.accumulo.core.client.TableDeletedException; import org.apache.accumulo.core.client.TableNotFoundException; import org.apache.accumulo.core.client.TableOfflineException; import org.apache.accumulo.core.client.sample.SamplerConfiguration; import org.apache.accumulo.core.clientImpl.ClientContext; import org.apache.accumulo.core.clientImpl.OfflineScanner; import org.apache.accumulo.core.clientImpl.ScannerImpl; import org.apache.accumulo.core.clientImpl.Tables; import org.apache.accumulo.core.clientImpl.TabletLocator; import org.apache.accumulo.core.data.Key; import org.apache.accumulo.core.data.Range; import org.apache.accumulo.core.data.TableId; import org.apache.accumulo.core.data.Value; import org.apache.accumulo.core.dataImpl.KeyExtent; import org.apache.accumulo.core.master.state.tables.TableState; import org.apache.accumulo.core.security.Authorizations; import org.apache.accumulo.core.util.Pair; import org.apache.accumulo.hadoopImpl.mapreduce.lib.InputConfigurator; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.InputSplit; import org.apache.hadoop.mapreduce.JobContext; import org.apache.hadoop.mapreduce.RecordReader; import org.apache.hadoop.mapreduce.TaskAttemptContext; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * An implementation of {@link org.apache.hadoop.mapreduce.RecordReader} that converts Accumulo * {@link org.apache.accumulo.core.data.Key}/{@link org.apache.accumulo.core.data.Value} pairs to * the user's K/V types. */ public abstract class AccumuloRecordReader<K, V> extends RecordReader<K, V> { private static final Logger log = LoggerFactory.getLogger(AccumuloRecordReader.class); // class to serialize configuration under in the job private final Class<?> CLASS; protected long numKeysRead; protected AccumuloClient client; protected Iterator<Map.Entry<Key, Value>> scannerIterator; protected ScannerBase scannerBase; protected RangeInputSplit split; public AccumuloRecordReader(Class<?> callingClass) { this.CLASS = callingClass; } /** * The Key that should be returned to the client */ protected K currentK = null; /** * The Value that should be return to the client */ protected V currentV = null; /** * The Key that is used to determine progress in the current InputSplit. It is not returned to the * client and is only used internally */ protected Key currentKey = null; /** * Extracts Iterators settings from the context to be used by RecordReader. * * @param context * the Hadoop context for the configured job * @return List of iterator settings for given table */ private List<IteratorSetting> contextIterators(TaskAttemptContext context) { return InputConfigurator.getIterators(CLASS, context.getConfiguration()); } /** * Configures the iterators on a scanner for the given table name. Will attempt to use * configuration from the InputSplit, on failure will try to extract them from TaskAttemptContext. * * @param context * the Hadoop context for the configured job * @param scanner * the scanner for which to configure the iterators * @param split * InputSplit containing configurations */ private void setupIterators(TaskAttemptContext context, ScannerBase scanner, RangeInputSplit split) { List<IteratorSetting> iterators = null; if (split == null) { iterators = contextIterators(context); } else { iterators = split.getIterators(); if (iterators == null) { iterators = contextIterators(context); } } for (IteratorSetting iterator : iterators) scanner.addScanIterator(iterator); } @Override public void initialize(InputSplit inSplit, TaskAttemptContext attempt) throws IOException { split = (RangeInputSplit) inSplit; log.debug("Initializing input split: " + split); Configuration conf = attempt.getConfiguration(); client = createClient(attempt, this.CLASS); ClientContext context = (ClientContext) client; Authorizations authorizations = InputConfigurator.getScanAuthorizations(CLASS, conf); String classLoaderContext = InputConfigurator.getClassLoaderContext(CLASS, conf); String table = split.getTableName(); // in case the table name changed, we can still use the previous name for terms of // configuration, // but the scanner will use the table id resolved at job setup time InputTableConfig tableConfig = InputConfigurator.getInputTableConfig(CLASS, conf, split.getTableName()); log.debug("Creating client with user: " + client.whoami()); log.debug("Creating scanner for table: " + table); log.debug("Authorizations are: " + authorizations); if (split instanceof BatchInputSplit) { BatchInputSplit batchSplit = (BatchInputSplit) split; BatchScanner scanner; try { // Note: BatchScanner will use at most one thread per tablet, currently BatchInputSplit // will not span tablets int scanThreads = 1; scanner = context.createBatchScanner(split.getTableName(), authorizations, scanThreads); setupIterators(attempt, scanner, split); if (classLoaderContext != null) { scanner.setClassLoaderContext(classLoaderContext); } } catch (TableNotFoundException e) { e.printStackTrace(); throw new IOException(e); } scanner.setRanges(batchSplit.getRanges()); scannerBase = scanner; } else { Scanner scanner; Boolean isOffline = split.isOffline(); if (isOffline == null) { isOffline = tableConfig.isOfflineScan(); } Boolean isIsolated = split.isIsolatedScan(); if (isIsolated == null) { isIsolated = tableConfig.shouldUseIsolatedScanners(); } Boolean usesLocalIterators = split.usesLocalIterators(); if (usesLocalIterators == null) { usesLocalIterators = tableConfig.shouldUseLocalIterators(); } try { if (isOffline) { scanner = new OfflineScanner(context, TableId.of(split.getTableId()), authorizations); } else { // Not using public API to create scanner so that we can use table ID // Table ID is used in case of renames during M/R job scanner = new ScannerImpl(context, TableId.of(split.getTableId()), authorizations); } if (isIsolated) { log.info("Creating isolated scanner"); scanner = new IsolatedScanner(scanner); } if (usesLocalIterators) { log.info("Using local iterators"); scanner = new ClientSideIteratorScanner(scanner); } setupIterators(attempt, scanner, split); } catch (RuntimeException e) { throw new IOException(e); } scanner.setRange(split.getRange()); scannerBase = scanner; } Collection<IteratorSetting.Column> columns = split.getFetchedColumns(); if (columns == null) { columns = tableConfig.getFetchedColumns(); } // setup a scanner within the bounds of this split for (Pair<Text, Text> c : columns) { if (c.getSecond() != null) { log.debug("Fetching column " + c.getFirst() + ":" + c.getSecond()); scannerBase.fetchColumn(c.getFirst(), c.getSecond()); } else { log.debug("Fetching column family " + c.getFirst()); scannerBase.fetchColumnFamily(c.getFirst()); } } SamplerConfiguration samplerConfig = split.getSamplerConfiguration(); if (samplerConfig == null) { samplerConfig = tableConfig.getSamplerConfiguration(); } if (samplerConfig != null) { scannerBase.setSamplerConfiguration(samplerConfig); } Map<String, String> executionHints = split.getExecutionHints(); if (executionHints == null || executionHints.isEmpty()) { executionHints = tableConfig.getExecutionHints(); } if (executionHints != null) { scannerBase.setExecutionHints(executionHints); } scannerIterator = scannerBase.iterator(); numKeysRead = 0; } @Override public void close() { if (scannerBase != null) { scannerBase.close(); } if (client != null) { client.close(); } } @Override public float getProgress() { if (numKeysRead > 0 && currentKey == null) return 1.0f; return split.getProgress(currentKey); } @Override public K getCurrentKey() { return currentK; } @Override public V getCurrentValue() { return currentV; } /** * Check whether a configuration is fully configured to be used with an Accumulo * {@link org.apache.hadoop.mapreduce.InputFormat}. */ private static void validateOptions(JobContext context, Class<?> callingClass) throws IOException { InputConfigurator.checkJobStored(callingClass, context.getConfiguration()); try (AccumuloClient client = InputConfigurator.createClient(callingClass, context.getConfiguration())) { InputConfigurator.validatePermissions(callingClass, context.getConfiguration(), client); } } private static Map<String, Map<KeyExtent, List<Range>>> binOfflineTable(JobContext context, TableId tableId, List<Range> ranges, Class<?> callingClass) throws TableNotFoundException, AccumuloException { try (AccumuloClient client = createClient(context, callingClass)) { return InputConfigurator.binOffline(tableId, ranges, (ClientContext) client); } } public static List<InputSplit> getSplits(JobContext context, Class<?> callingClass) throws IOException { validateOptions(context, callingClass); Random random = new SecureRandom(); LinkedList<InputSplit> splits = new LinkedList<>(); try (AccumuloClient client = createClient(context, callingClass)) { Map<String, InputTableConfig> tableConfigs = InputConfigurator.getInputTableConfigs(callingClass, context.getConfiguration()); for (Map.Entry<String, InputTableConfig> tableConfigEntry : tableConfigs.entrySet()) { String tableName = tableConfigEntry.getKey(); InputTableConfig tableConfig = tableConfigEntry.getValue(); ClientContext clientContext = (ClientContext) client; TableId tableId; // resolve table name to id once, and use id from this point forward try { tableId = Tables.getTableId(clientContext, tableName); } catch (TableNotFoundException e) { throw new IOException(e); } boolean batchScan = InputConfigurator.isBatchScan(callingClass, context.getConfiguration()); boolean supportBatchScan = !(tableConfig.isOfflineScan() || tableConfig.shouldUseIsolatedScanners() || tableConfig.shouldUseLocalIterators()); if (batchScan && !supportBatchScan) throw new IllegalArgumentException("BatchScanner optimization not available for offline" + " scan, isolated, or local iterators"); boolean autoAdjust = tableConfig.shouldAutoAdjustRanges(); if (batchScan && !autoAdjust) throw new IllegalArgumentException( "AutoAdjustRanges must be enabled when using BatchScanner optimization"); List<Range> ranges = autoAdjust ? Range.mergeOverlapping(tableConfig.getRanges()) : tableConfig.getRanges(); if (ranges.isEmpty()) { ranges = new ArrayList<>(1); ranges.add(new Range()); } // get the metadata information for these ranges Map<String, Map<KeyExtent, List<Range>>> binnedRanges = new HashMap<>(); TabletLocator tl; try { if (tableConfig.isOfflineScan()) { binnedRanges = binOfflineTable(context, tableId, ranges, callingClass); while (binnedRanges == null) { // Some tablets were still online, try again // sleep randomly between 100 and 200 ms sleepUninterruptibly(100 + random.nextInt(100), TimeUnit.MILLISECONDS); binnedRanges = binOfflineTable(context, tableId, ranges, callingClass); } } else { tl = InputConfigurator.getTabletLocator(callingClass, context.getConfiguration(), tableId); // its possible that the cache could contain complete, but old information about a // tables tablets... so clear it tl.invalidateCache(); while (!tl.binRanges(clientContext, ranges, binnedRanges).isEmpty()) { String tableIdStr = tableId.canonical(); if (!Tables.exists(clientContext, tableId)) throw new TableDeletedException(tableIdStr); if (Tables.getTableState(clientContext, tableId) == TableState.OFFLINE) throw new TableOfflineException(Tables.getTableOfflineMsg(clientContext, tableId)); binnedRanges.clear(); log.warn("Unable to locate bins for specified ranges. Retrying."); // sleep randomly between 100 and 200 ms sleepUninterruptibly(100 + random.nextInt(100), TimeUnit.MILLISECONDS); tl.invalidateCache(); } } } catch (TableOfflineException | TableNotFoundException | AccumuloException | AccumuloSecurityException e) { throw new IOException(e); } // all of this code will add either range per each locations or split ranges and add // range-location split // Map from Range to Array of Locations, we only use this if we're don't split HashMap<Range, ArrayList<String>> splitsToAdd = null; if (!autoAdjust) splitsToAdd = new HashMap<>(); HashMap<String, String> hostNameCache = new HashMap<>(); for (Map.Entry<String, Map<KeyExtent, List<Range>>> tserverBin : binnedRanges.entrySet()) { String ip = tserverBin.getKey().split(":", 2)[0]; String location = hostNameCache.get(ip); if (location == null) { InetAddress inetAddress = InetAddress.getByName(ip); location = inetAddress.getCanonicalHostName(); hostNameCache.put(ip, location); } for (Map.Entry<KeyExtent, List<Range>> extentRanges : tserverBin.getValue().entrySet()) { Range ke = extentRanges.getKey().toDataRange(); if (batchScan) { // group ranges by tablet to be read by a BatchScanner ArrayList<Range> clippedRanges = new ArrayList<>(); for (Range r : extentRanges.getValue()) clippedRanges.add(ke.clip(r)); BatchInputSplit split = new BatchInputSplit(tableName, tableId, clippedRanges, new String[] { location }); SplitUtils.updateSplit(split, tableConfig); splits.add(split); } else { // not grouping by tablet for (Range r : extentRanges.getValue()) { if (autoAdjust) { // divide ranges into smaller ranges, based on the tablets RangeInputSplit split = new RangeInputSplit(tableName, tableId.canonical(), ke.clip(r), new String[] { location }); SplitUtils.updateSplit(split, tableConfig); split.setOffline(tableConfig.isOfflineScan()); split.setIsolatedScan(tableConfig.shouldUseIsolatedScanners()); split.setUsesLocalIterators(tableConfig.shouldUseLocalIterators()); splits.add(split); } else { // don't divide ranges ArrayList<String> locations = splitsToAdd.get(r); if (locations == null) locations = new ArrayList<>(1); locations.add(location); splitsToAdd.put(r, locations); } } } } } if (!autoAdjust) for (Map.Entry<Range, ArrayList<String>> entry : splitsToAdd.entrySet()) { RangeInputSplit split = new RangeInputSplit(tableName, tableId.canonical(), entry.getKey(), entry.getValue().toArray(new String[0])); SplitUtils.updateSplit(split, tableConfig); split.setOffline(tableConfig.isOfflineScan()); split.setIsolatedScan(tableConfig.shouldUseIsolatedScanners()); split.setUsesLocalIterators(tableConfig.shouldUseLocalIterators()); splits.add(split); } } } return splits; } /** * Creates {@link AccumuloClient} from the configuration */ private static AccumuloClient createClient(JobContext context, Class<?> callingClass) { return InputConfigurator.createClient(callingClass, context.getConfiguration()); } }