hbase-common/src/main/java/org/apache/hadoop/hbase/trace/TraceUtil.java

   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.hbase.trace;
  19
  20 import org.apache.hadoop.conf.Configuration;
  21 import org.apache.htrace.core.HTraceConfiguration;
  22 import org.apache.htrace.core.Sampler;
  23 import org.apache.htrace.core.Span;
  24 import org.apache.htrace.core.SpanReceiver;
  25 import org.apache.htrace.core.TraceScope;
  26 import org.apache.htrace.core.Tracer;
  27 import org.apache.yetus.audience.InterfaceAudience;
  28
  29 /**
  30  * This wrapper class provides functions for accessing htrace 4+ functionality in a simplified way.
  31  */
  32 @InterfaceAudience.Private
  33 public final class TraceUtil {
  34   private static HTraceConfiguration conf;
  35   private static Tracer tracer;
  36
  37   private TraceUtil() {
  38   }
  39
  40   public static void initTracer(Configuration c) {
  41     if (c != null) {
  42       conf = new HBaseHTraceConfiguration(c);
  43     }
  44
  45     if (tracer == null && conf != null) {
  46       tracer = new Tracer.Builder("Tracer").conf(conf).build();
  47     }
  48   }
  49
  50   /**
  51    * Wrapper method to create new TraceScope with the given description
  52    * @return TraceScope or null when not tracing
  53    */
  54   public static TraceScope createTrace(String description) {
  55     return (tracer == null) ? null : tracer.newScope(description);
  56   }
  57
  58   /**
  59    * Wrapper method to create new child TraceScope with the given description
  60    * and parent scope's spanId
  61    * @param span parent span
  62    * @return TraceScope or null when not tracing
  63    */
  64   public static TraceScope createTrace(String description, Span span) {
  65     if (span == null) {
  66       return createTrace(description);
  67     }
  68
  69     return (tracer == null) ? null : tracer.newScope(description, span.getSpanId());
  70   }
  71
  72   /**
  73    * Wrapper method to add new sampler to the default tracer
  74    * @return true if added, false if it was already added
  75    */
  76   public static boolean addSampler(Sampler sampler) {
  77     if (sampler == null) {
  78       return false;
  79     }
  80
  81     return (tracer == null) ? false : tracer.addSampler(sampler);
  82   }
  83
  84   /**
  85    * Wrapper method to add key-value pair to TraceInfo of actual span
  86    */
  87   public static void addKVAnnotation(String key, String value){
  88     Span span = Tracer.getCurrentSpan();
  89     if (span != null) {
  90       span.addKVAnnotation(key, value);
  91     }
  92   }
  93
  94   /**
  95    * Wrapper method to add receiver to actual tracerpool
  96    * @return true if successfull, false if it was already added
  97    */
  98   public static boolean addReceiver(SpanReceiver rcvr) {
  99     return (tracer == null) ? false : tracer.getTracerPool().addReceiver(rcvr);
 100   }
 101
 102   /**
 103    * Wrapper method to remove receiver from actual tracerpool
 104    * @return true if removed, false if doesn't exist
 105    */
 106   public static boolean removeReceiver(SpanReceiver rcvr) {
 107     return (tracer == null) ? false : tracer.getTracerPool().removeReceiver(rcvr);
 108   }
 109
 110   /**
 111    * Wrapper method to add timeline annotiation to current span with given message
 112    */
 113   public static void addTimelineAnnotation(String msg) {
 114     Span span = Tracer.getCurrentSpan();
 115     if (span != null) {
 116       span.addTimelineAnnotation(msg);
 117     }
 118   }
 119
 120   /**
 121    * Wrap runnable with current tracer and description
 122    * @param runnable to wrap
 123    * @return wrapped runnable or original runnable when not tracing
 124    */
 125   public static Runnable wrap(Runnable runnable, String description) {
 126     return (tracer == null) ? runnable : tracer.wrap(runnable, description);
 127   }
 128 }