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 * <p/> * http://www.apache.org/licenses/LICENSE-2.0 * <p/> * 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.hadoop.hdfs.server.datanode; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_METRICS_LOGGER_PERIOD_SECONDS_KEY; import static org.junit.Assert.assertNotNull; import static org.junit.Assert.assertNull; import static org.junit.Assert.assertTrue; import java.io.File; import java.io.IOException; import java.net.InetSocketAddress; import java.util.Collections; import java.util.List; import java.util.Random; import java.util.concurrent.TimeoutException; import java.util.regex.Pattern; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.commons.logging.impl.Log4JLogger; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.CommonConfigurationKeys; import org.apache.hadoop.fs.FileUtil; import org.apache.hadoop.hdfs.DFSConfigKeys; import org.apache.hadoop.hdfs.HdfsConfiguration; import org.apache.hadoop.hdfs.MiniDFSCluster; import org.apache.hadoop.metrics2.util.MBeans; import org.apache.hadoop.test.GenericTestUtils; import org.apache.log4j.Appender; import org.apache.log4j.AppenderSkeleton; import org.apache.log4j.AsyncAppender; import org.apache.log4j.spi.LoggingEvent; import org.junit.After; import org.junit.Assert; import org.junit.Rule; import org.junit.Test; import org.junit.rules.Timeout; import com.google.common.base.Supplier; /** * Test periodic logging of DataNode metrics. */ public class TestDataNodeMetricsLogger { static final Log LOG = LogFactory.getLog(TestDataNodeMetricsLogger.class); private static final String DATA_DIR = MiniDFSCluster.getBaseDirectory() + "data"; private final static InetSocketAddress NN_ADDR = new InetSocketAddress("localhost", 5020); private DataNode dn; static final Random random = new Random(System.currentTimeMillis()); @Rule public Timeout timeout = new Timeout(300000); /** * Starts an instance of DataNode * * @throws IOException */ public void startDNForTest(boolean enableMetricsLogging) throws IOException { Configuration conf = new HdfsConfiguration(); conf.set(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY, DATA_DIR); conf.set(DFSConfigKeys.DFS_DATANODE_ADDRESS_KEY, "0.0.0.0:0"); conf.set(DFSConfigKeys.DFS_DATANODE_HTTP_ADDRESS_KEY, "0.0.0.0:0"); conf.set(DFSConfigKeys.DFS_DATANODE_IPC_ADDRESS_KEY, "0.0.0.0:0"); conf.setInt(CommonConfigurationKeys.IPC_CLIENT_CONNECT_MAX_RETRIES_KEY, 0); conf.setInt(DFS_DATANODE_METRICS_LOGGER_PERIOD_SECONDS_KEY, enableMetricsLogging ? 1 : 0); // If enabled, log early and log often dn = InternalDataNodeTestUtils.startDNWithMockNN(conf, NN_ADDR, DATA_DIR); } /** * Cleans the resources and closes the instance of datanode * * @throws IOException * if an error occurred */ @After public void tearDown() throws IOException { if (dn != null) { try { dn.shutdown(); } catch (Exception e) { LOG.error("Cannot close: ", e); } finally { File dir = new File(DATA_DIR); if (dir.exists()) Assert.assertTrue("Cannot delete data-node dirs", FileUtil.fullyDelete(dir)); } } dn = null; } @Test public void testMetricsLoggerOnByDefault() throws IOException { startDNForTest(true); assertNotNull(dn); assertNotNull(dn.getMetricsLoggerTimer()); } @Test public void testDisableMetricsLogger() throws IOException { startDNForTest(false); assertNotNull(dn); assertNull(dn.getMetricsLoggerTimer()); } @Test public void testMetricsLoggerIsAsync() throws IOException { startDNForTest(true); assertNotNull(dn); org.apache.log4j.Logger logger = ((Log4JLogger) DataNode.METRICS_LOG).getLogger(); @SuppressWarnings("unchecked") List<Appender> appenders = Collections.list(logger.getAllAppenders()); assertTrue(appenders.get(0) instanceof AsyncAppender); } /** * Publish a fake metric under the "Hadoop:" domain and ensure it is logged by * the metrics logger. */ @Test public void testMetricsLogOutput() throws IOException, InterruptedException, TimeoutException { TestFakeMetric metricsProvider = new TestFakeMetric(); MBeans.register(this.getClass().getSimpleName(), "DummyMetrics", metricsProvider); startDNForTest(true); assertNotNull(dn); final PatternMatchingAppender appender = new PatternMatchingAppender("^.*FakeMetric.*$"); addAppender(DataNode.METRICS_LOG, appender); // Ensure that the supplied pattern was matched. GenericTestUtils.waitFor(new Supplier<Boolean>() { @Override public Boolean get() { return appender.isMatched(); } }, 1000, 60000); dn.shutdown(); } private void addAppender(Log log, Appender appender) { org.apache.log4j.Logger logger = ((Log4JLogger) log).getLogger(); @SuppressWarnings("unchecked") List<Appender> appenders = Collections.list(logger.getAllAppenders()); ((AsyncAppender) appenders.get(0)).addAppender(appender); } public interface TestFakeMetricMXBean { int getFakeMetric(); } /** * MBean for testing */ public static class TestFakeMetric implements TestFakeMetricMXBean { @Override public int getFakeMetric() { return 0; } } /** * An appender that matches logged messages against the given regular * expression. */ public static class PatternMatchingAppender extends AppenderSkeleton { private final Pattern pattern; private volatile boolean matched; public PatternMatchingAppender(String pattern) { this.pattern = Pattern.compile(pattern); this.matched = false; } public boolean isMatched() { return matched; } @Override protected void append(LoggingEvent event) { if (pattern.matcher(event.getMessage().toString()).matches()) { matched = true; } } @Override public void close() { } @Override public boolean requiresLayout() { return false; } } }