[120] | 1 | /** |
---|
| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
---|
| 3 | * or more contributor license agreements. See the NOTICE file |
---|
| 4 | * distributed with this work for additional information |
---|
| 5 | * regarding copyright ownership. The ASF licenses this file |
---|
| 6 | * to you under the Apache License, Version 2.0 (the |
---|
| 7 | * "License"); you may not use this file except in compliance |
---|
| 8 | * with the License. You may obtain a copy of the License at |
---|
| 9 | * |
---|
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
---|
| 11 | * |
---|
| 12 | * Unless required by applicable law or agreed to in writing, software |
---|
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
---|
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
---|
| 15 | * See the License for the specific language governing permissions and |
---|
| 16 | * limitations under the License. |
---|
| 17 | */ |
---|
| 18 | package org.apache.hadoop.metrics; |
---|
| 19 | |
---|
| 20 | import java.net.InetAddress; |
---|
| 21 | import java.net.UnknownHostException; |
---|
| 22 | |
---|
| 23 | import org.apache.commons.logging.Log; |
---|
| 24 | import org.apache.commons.logging.LogFactory; |
---|
| 25 | |
---|
| 26 | /** |
---|
| 27 | * Utility class to simplify creation and reporting of hadoop metrics. |
---|
| 28 | * |
---|
| 29 | * For examples of usage, see NameNodeMetrics. |
---|
| 30 | * @see org.apache.hadoop.metrics.MetricsRecord |
---|
| 31 | * @see org.apache.hadoop.metrics.MetricsContext |
---|
| 32 | * @see org.apache.hadoop.metrics.ContextFactory |
---|
| 33 | */ |
---|
| 34 | public class MetricsUtil { |
---|
| 35 | |
---|
| 36 | public static final Log LOG = |
---|
| 37 | LogFactory.getLog(MetricsUtil.class); |
---|
| 38 | |
---|
| 39 | /** |
---|
| 40 | * Don't allow creation of a new instance of Metrics |
---|
| 41 | */ |
---|
| 42 | private MetricsUtil() {} |
---|
| 43 | |
---|
| 44 | public static MetricsContext getContext(String contextName) { |
---|
| 45 | return getContext(contextName, contextName); |
---|
| 46 | } |
---|
| 47 | |
---|
| 48 | /** |
---|
| 49 | * Utility method to return the named context. |
---|
| 50 | * If the desired context cannot be created for any reason, the exception |
---|
| 51 | * is logged, and a null context is returned. |
---|
| 52 | */ |
---|
| 53 | public static MetricsContext getContext(String refName, String contextName) { |
---|
| 54 | MetricsContext metricsContext; |
---|
| 55 | try { |
---|
| 56 | metricsContext = |
---|
| 57 | ContextFactory.getFactory().getContext(refName, contextName); |
---|
| 58 | if (!metricsContext.isMonitoring()) { |
---|
| 59 | metricsContext.startMonitoring(); |
---|
| 60 | } |
---|
| 61 | } catch (Exception ex) { |
---|
| 62 | LOG.error("Unable to create metrics context " + contextName, ex); |
---|
| 63 | metricsContext = ContextFactory.getNullContext(contextName); |
---|
| 64 | } |
---|
| 65 | return metricsContext; |
---|
| 66 | } |
---|
| 67 | |
---|
| 68 | /** |
---|
| 69 | * Utility method to create and return new metrics record instance within the |
---|
| 70 | * given context. This record is tagged with the host name. |
---|
| 71 | * |
---|
| 72 | * @param context the context |
---|
| 73 | * @param recordName name of the record |
---|
| 74 | * @return newly created metrics record |
---|
| 75 | */ |
---|
| 76 | public static MetricsRecord createRecord(MetricsContext context, |
---|
| 77 | String recordName) |
---|
| 78 | { |
---|
| 79 | MetricsRecord metricsRecord = context.createRecord(recordName); |
---|
| 80 | metricsRecord.setTag("hostName", getHostName()); |
---|
| 81 | return metricsRecord; |
---|
| 82 | } |
---|
| 83 | |
---|
| 84 | /** |
---|
| 85 | * Returns the host name. If the host name is unobtainable, logs the |
---|
| 86 | * exception and returns "unknown". |
---|
| 87 | */ |
---|
| 88 | private static String getHostName() { |
---|
| 89 | String hostName = null; |
---|
| 90 | try { |
---|
| 91 | hostName = InetAddress.getLocalHost().getHostName(); |
---|
| 92 | } |
---|
| 93 | catch (UnknownHostException ex) { |
---|
| 94 | LOG.info("Unable to obtain hostName", ex); |
---|
| 95 | hostName = "unknown"; |
---|
| 96 | } |
---|
| 97 | return hostName; |
---|
| 98 | } |
---|
| 99 | |
---|
| 100 | } |
---|