abstractdog commented on code in PR #98: URL: https://github.com/apache/tez/pull/98#discussion_r1003254516
########## tez-common/src/main/java/org/apache/tez/util/LoggingUtils.java: ########## @@ -0,0 +1,147 @@ +/** +* 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.tez.util; + +import java.lang.reflect.Constructor; +import java.lang.reflect.Field; +import java.lang.reflect.Modifier; +import java.util.Arrays; +import java.util.Hashtable; + +import org.apache.hadoop.conf.Configuration; +import org.apache.log4j.helpers.ThreadLocalMap; +import org.apache.tez.dag.api.TezConfiguration; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +public final class LoggingUtils { + private static final Logger LOG = LoggerFactory.getLogger(LoggingUtils.class); + + private LoggingUtils() {} + + @SuppressWarnings("unchecked") + public static void initLoggingContext(ThreadLocalMap threadLocalMap, Configuration conf, + String dagId, String taskAttemptId) { + Hashtable<String, String> data = (Hashtable<String, String>) threadLocalMap.get(); + if (data == null) { + data = new NonClonableHashtable<String, String>(); + threadLocalMap.set(data); + } + data.put("dagId", dagId == null ? "" : dagId); + data.put("taskAttemptId", taskAttemptId == null ? "" : taskAttemptId); + + String[] mdcKeys = conf.getStrings(TezConfiguration.TEZ_MDC_CUSTOM_KEYS, + TezConfiguration.TEZ_MDC_CUSTOM_KEYS_DEFAULT); + + if (mdcKeys.length == 0) { + return; + } + + String[] mdcKeysValuesFrom = conf.getStrings(TezConfiguration.TEZ_MDC_CUSTOM_KEYS_CONF_PROPS, + TezConfiguration.TEZ_MDC_CUSTOM_KEYS_CONF_PROPS_DEFAULT); + LOG.info("MDC_LOGGING: setting up MDC keys: keys: {} / conf: {}", Arrays.asList(mdcKeys), + Arrays.asList(mdcKeysValuesFrom)); + + int i = 0; + for (String mdcKey : mdcKeys) { + // don't want to fail on incorrect mdc key settings, but warn in app logs + if (mdcKey.isEmpty() || mdcKeysValuesFrom.length < i + 1) { + LOG.warn("cannot set mdc key: {}", mdcKey); + break; + } + + String mdcValue = mdcKeysValuesFrom[i] == null ? "" : conf.get(mdcKeysValuesFrom[i]); + // MDC is backed by a Hashtable, let's prevent NPE because of null values + if (mdcValue != null) { + data.put(mdcKey, mdcValue); + } else { + LOG.warn("MDC_LOGGING: mdc value is null for key: {}, config key: {}", mdcKey, + mdcKeysValuesFrom[i]); + } + + i++; + } + } + + public static String getPatternForAM(Configuration conf) { + return conf.get(TezConfiguration.TEZ_LOG_PATTERN_LAYOUT_AM, null); + } + + public static String getPatternForTask(Configuration conf) { + return conf.get(TezConfiguration.TEZ_LOG_PATTERN_LAYOUT_TASK, null); + } + + /** + * This method is for setting a NonClonableHashtable into log4j's mdc. Reflection hacks are + * needed, because MDC.mdc is well protected (final static MDC mdc = new MDC();). The logic below + * is supposed to be called once per JVM, so it's not a subject to performance bottlenecks. For + * further details of this solution, please check NonClonableHashtable class, which is set into + * the ThreadLocalMap. A wrong outcome of this method (any kind of runtime/reflection problems) + * should not affect the DAGAppMaster/TezChild. In case of an exception a ThreadLocalMap is + * returned, but it won't affect the content of the MDC. + */ + @SuppressWarnings("unchecked") + public static ThreadLocalMap setupLog4j() { + ThreadLocalMap mdcContext = new ThreadLocalMap(); + mdcContext.set(new NonClonableHashtable<String, String>()); + + try { + final Constructor<?>[] constructors = org.apache.log4j.MDC.class.getDeclaredConstructors(); Review Comment: log4j, intentionally, the whole hack implemented in this method is log4j specific -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
