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.pig.backend.hadoop.executionengine; import java.io.File; import java.io.IOException; import java.io.PrintStream; import java.net.URL; import java.util.Iterator; import java.util.Map; import java.util.Properties; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hdfs.DistributedFileSystem; import org.apache.hadoop.mapred.JobConf; import org.apache.pig.PigException; import org.apache.pig.backend.BackendException; import org.apache.pig.backend.datastorage.DataStorage; import org.apache.pig.backend.executionengine.ExecException; import org.apache.pig.backend.executionengine.ExecutionEngine; import org.apache.pig.backend.hadoop.datastorage.ConfigurationUtil; import org.apache.pig.backend.hadoop.datastorage.HDataStorage; import org.apache.pig.backend.hadoop.executionengine.fetch.FetchLauncher; import org.apache.pig.backend.hadoop.executionengine.fetch.FetchOptimizer; import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MRConfiguration; import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator; import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan; import org.apache.pig.backend.hadoop.executionengine.util.MapRedUtil; import org.apache.pig.backend.hadoop.streaming.HadoopExecutableManager; import org.apache.pig.impl.PigContext; import org.apache.pig.impl.logicalLayer.FrontendException; import org.apache.pig.impl.plan.OperatorKey; import org.apache.pig.impl.plan.PlanException; import org.apache.pig.impl.plan.VisitorException; import org.apache.pig.impl.streaming.ExecutableManager; import org.apache.pig.impl.util.Utils; import org.apache.pig.newplan.Operator; import org.apache.pig.newplan.logical.relational.LOForEach; import org.apache.pig.newplan.logical.relational.LogToPhyTranslationVisitor; import org.apache.pig.newplan.logical.relational.LogicalPlan; import org.apache.pig.newplan.logical.relational.LogicalRelationalOperator; import org.apache.pig.tools.pigstats.PigStats; import com.google.common.collect.Maps; public abstract class HExecutionEngine implements ExecutionEngine { private static final Log LOG = LogFactory.getLog(HExecutionEngine.class); public static final String HADOOP_SITE = "hadoop-site.xml"; public static final String CORE_SITE = "core-site.xml"; public static final String YARN_SITE = "yarn-site.xml"; public static final String CORE_DEFAULT_SITE = "core-default.xml"; public static final String MAPRED_DEFAULT_SITE = "mapred-default.xml"; public static final String YARN_DEFAULT_SITE = "yarn-default.xml"; public static final String FILE_SYSTEM_LOCATION = "fs.default.name"; public static final String ALTERNATIVE_FILE_SYSTEM_LOCATION = "fs.defaultFS"; public static final String LOCAL = "local"; protected PigContext pigContext; protected DataStorage ds; protected Launcher launcher; // key: the operator key from the logical plan that originated the physical plan // val: the operator key for the root of the phyisical plan protected Map<OperatorKey, OperatorKey> logicalToPhysicalKeys; protected Map<Operator, PhysicalOperator> newLogToPhyMap; public HExecutionEngine(PigContext pigContext) { this.pigContext = pigContext; this.ds = null; this.logicalToPhysicalKeys = Maps.newHashMap(); } @Deprecated public JobConf getJobConf() { JobConf jc = new JobConf(false); Utils.recomputeProperties(jc, pigContext.getProperties()); return jc; } @Override public DataStorage getDataStorage() { return this.ds; } @Override public void init() throws ExecException { init(this.pigContext.getProperties()); } public JobConf getLocalConf() { JobConf jc = new JobConf(false); jc.addResource(CORE_DEFAULT_SITE); jc.addResource(MAPRED_DEFAULT_SITE); jc.addResource(YARN_DEFAULT_SITE); return jc; } public JobConf getExecConf(Properties properties) throws ExecException { JobConf jc = null; // Check existence of user provided configs String isHadoopConfigsOverriden = properties.getProperty("pig.use.overriden.hadoop.configs"); if (isHadoopConfigsOverriden != null && isHadoopConfigsOverriden.equals("true")) { jc = new JobConf(ConfigurationUtil.toConfiguration(properties)); } else { // Check existence of hadoop-site.xml or core-site.xml in // classpath if user provided confs are not being used Configuration testConf = new Configuration(); ClassLoader cl = testConf.getClassLoader(); URL hadoop_site = cl.getResource(HADOOP_SITE); URL core_site = cl.getResource(CORE_SITE); if (hadoop_site == null && core_site == null) { throw new ExecException( "Cannot find hadoop configurations in classpath " + "(neither hadoop-site.xml nor core-site.xml was found in the classpath)." + " If you plan to use local mode, please put -x local option in command line", 4010); } jc = new JobConf(); } jc.addResource("pig-cluster-hadoop-site.xml"); jc.addResource(YARN_SITE); return jc; } private void init(Properties properties) throws ExecException { String cluster = null; String nameNode = null; // We need to build a configuration object first in the manner described // below and then get back a properties object to inspect the // JOB_TRACKER_LOCATION and FILE_SYSTEM_LOCATION. The reason to do this // is if we looked only at the existing properties object, we may not // get the right settings. So we want to read the configurations in the // order specified below and only then look for JOB_TRACKER_LOCATION and // FILE_SYSTEM_LOCATION. // Hadoop by default specifies two resources, loaded in-order from the // classpath: // 1. hadoop-default.xml : Read-only defaults for hadoop. // 2. hadoop-site.xml: Site-specific configuration for a given hadoop // installation. // Now add the settings from "properties" object to override any // existing properties All of the above is accomplished in the method // call below JobConf jc = null; if (!this.pigContext.getExecType().isLocal()) { jc = getExecConf(properties); // Trick to invoke static initializer of DistributedFileSystem to // add hdfs-default.xml into configuration new DistributedFileSystem(); } else { // If we are running in local mode we dont read the hadoop conf file if (properties.getProperty(MRConfiguration.FRAMEWORK_NAME) == null) { properties.setProperty(MRConfiguration.FRAMEWORK_NAME, LOCAL); } properties.setProperty(MRConfiguration.JOB_TRACKER, LOCAL); properties.setProperty(FILE_SYSTEM_LOCATION, "file:///"); properties.setProperty(ALTERNATIVE_FILE_SYSTEM_LOCATION, "file:///"); jc = getLocalConf(); } // the method below alters the properties object by overriding the // hadoop properties with the values from properties and recomputing // the properties Utils.recomputeProperties(jc, properties); cluster = jc.get(MRConfiguration.JOB_TRACKER); nameNode = jc.get(FILE_SYSTEM_LOCATION); if (nameNode == null) { nameNode = (String) pigContext.getProperties().get(ALTERNATIVE_FILE_SYSTEM_LOCATION); } if (cluster != null && cluster.length() > 0) { if (!cluster.contains(":") && !cluster.equalsIgnoreCase(LOCAL)) { cluster = cluster + ":50020"; } properties.setProperty(MRConfiguration.JOB_TRACKER, cluster); } if (nameNode != null && nameNode.length() > 0) { if (!nameNode.contains(":") && !nameNode.equalsIgnoreCase(LOCAL)) { nameNode = nameNode + ":8020"; } properties.setProperty(FILE_SYSTEM_LOCATION, nameNode); } LOG.info("Connecting to hadoop file system at: " + (nameNode == null ? LOCAL : nameNode)); // constructor sets DEFAULT_REPLICATION_FACTOR_KEY ds = new HDataStorage(properties); if (cluster != null && !cluster.equalsIgnoreCase(LOCAL)) { LOG.info("Connecting to map-reduce job tracker at: " + jc.get(MRConfiguration.JOB_TRACKER)); } } public PhysicalPlan compile(LogicalPlan plan, Properties properties) throws FrontendException { if (plan == null) { int errCode = 2041; String msg = "No Plan to compile"; throw new FrontendException(msg, errCode, PigException.BUG); } // translate new logical plan to physical plan LogToPhyTranslationVisitor translator = new LogToPhyTranslationVisitor(plan); translator.setPigContext(pigContext); translator.visit(); newLogToPhyMap = translator.getLogToPhyMap(); return translator.getPhysicalPlan(); } public Map<Operator, PhysicalOperator> getLogToPhyMap() { return newLogToPhyMap; } public Map<LOForEach, Map<LogicalRelationalOperator, PhysicalOperator>> getForEachInnerLogToPhyMap( LogicalPlan plan) { Map<LOForEach, Map<LogicalRelationalOperator, PhysicalOperator>> result = Maps.newHashMap(); Iterator<Operator> outerIter = plan.getOperators(); while (outerIter.hasNext()) { Operator oper = outerIter.next(); if (oper instanceof LOForEach) { LogicalPlan innerPlan = ((LOForEach) oper).getInnerPlan(); Map<LogicalRelationalOperator, PhysicalOperator> innerOpMap = Maps.newHashMap(); Iterator<Operator> innerIter = innerPlan.getOperators(); while (innerIter.hasNext()) { Operator innerOper = innerIter.next(); innerOpMap.put(((LogicalRelationalOperator) innerOper), newLogToPhyMap.get(innerOper)); } result.put((LOForEach) oper, innerOpMap); } } return result; } @Override public PigStats launchPig(LogicalPlan lp, String grpName, PigContext pc) throws FrontendException, ExecException { try { PhysicalPlan pp = compile(lp, pc.getProperties()); //if the compiled physical plan fulfills the requirements of the //fetch optimizer, then further transformations / MR jobs creations are //skipped; a SimpleFetchPigStats will be returned through which the result //can be directly fetched from the underlying storage if (FetchOptimizer.isPlanFetchable(pc, pp)) { return new FetchLauncher(pc).launchPig(pp); } return launcher.launchPig(pp, grpName, pigContext); } catch (ExecException e) { throw (ExecException) e; } catch (FrontendException e) { throw (FrontendException) e; } catch (Exception e) { throw new ExecException(e); } finally { launcher.reset(); } } @Override public void explain(LogicalPlan lp, PigContext pc, PrintStream ps, String format, boolean verbose, File file, String suffix) throws PlanException, VisitorException, IOException, FrontendException { PrintStream pps = ps; PrintStream eps = ps; try { if (file != null) { pps = new PrintStream(new File(file, "physical_plan-" + suffix)); eps = new PrintStream(new File(file, "exec_plan-" + suffix)); } PhysicalPlan pp = compile(lp, pc.getProperties()); pp.explain(pps, format, verbose); MapRedUtil.checkLeafIsStore(pp, pigContext); if (FetchOptimizer.isPlanFetchable(pc, pp)) { new FetchLauncher(pigContext).explain(pp, pc, eps, format); return; } launcher.explain(pp, pigContext, eps, format, verbose); } finally { launcher.reset(); //Only close the stream if we opened it. if (file != null) { pps.close(); eps.close(); } } } @Override public Properties getConfiguration() { Properties properties = new Properties(); properties.putAll(pigContext.getProperties()); return properties; } @Override public void setConfiguration(Properties newConfiguration) throws ExecException { init(newConfiguration); } @Override public void setProperty(String property, String value) { Properties properties = pigContext.getProperties(); properties.put(property, value); } @Override public ExecutableManager getExecutableManager() { return new HadoopExecutableManager(); } @Override public void killJob(String jobID) throws BackendException { if (launcher != null) { launcher.killJob(jobID, getJobConf()); } } }