| /** |
| * 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.htrace; |
| |
| import java.io.IOException; |
| import java.util.Collection; |
| import java.util.HashSet; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.htrace.core.HTraceConfiguration; |
| import org.apache.htrace.core.SpanReceiver; |
| import org.apache.htrace.core.SpanReceiverBuilder; |
| import org.apache.htrace.core.Trace; |
| |
| /** |
| * This class provides functions for reading the names of SpanReceivers from |
| * hbase-site.xml, adding those SpanReceivers to the Tracer, and closing those |
| * SpanReceivers when appropriate. |
| */ |
| public class HBaseSpanReceiverHost { |
| public static final String SPAN_RECEIVERS_CONF_KEY = "hbase.trace.spanreceiver.classes"; |
| private static final Log LOG = LogFactory.getLog(HBaseSpanReceiverHost.class); |
| private Collection<SpanReceiver> receivers; |
| private Configuration conf; |
| private boolean closed = false; |
| |
| private static enum SingletonHolder { |
| INSTANCE; |
| Object lock = new Object(); |
| HBaseSpanReceiverHost host = null; |
| } |
| |
| public static HBaseSpanReceiverHost getInstance(Configuration conf) { |
| synchronized (SingletonHolder.INSTANCE.lock) { |
| if (SingletonHolder.INSTANCE.host != null) { |
| return SingletonHolder.INSTANCE.host; |
| } |
| |
| HBaseSpanReceiverHost host = new HBaseSpanReceiverHost(conf); |
| host.loadSpanReceivers(); |
| SingletonHolder.INSTANCE.host = host; |
| return SingletonHolder.INSTANCE.host; |
| } |
| |
| } |
| |
| HBaseSpanReceiverHost(Configuration conf) { |
| receivers = new HashSet<SpanReceiver>(); |
| this.conf = conf; |
| } |
| |
| /** |
| * Reads the names of classes specified in the |
| * "hbase.trace.spanreceiver.classes" property and instantiates and registers |
| * them with the Tracer as SpanReceiver's. |
| * |
| */ |
| public void loadSpanReceivers() { |
| String[] receiverNames = conf.getStrings(SPAN_RECEIVERS_CONF_KEY); |
| if (receiverNames == null || receiverNames.length == 0) { |
| return; |
| } |
| SpanReceiverBuilder builder = new SpanReceiverBuilder(new HBaseHTraceConfiguration(this.conf)); |
| for (String className : receiverNames) { |
| SpanReceiver receiver = builder.spanReceiverClass(className.trim()).build(); |
| if (receiver != null) { |
| receivers.add(receiver); |
| LOG.info("SpanReceiver " + className + " was loaded successfully."); |
| } |
| } |
| for (SpanReceiver rcvr : receivers) { |
| Trace.addReceiver(rcvr); |
| } |
| } |
| |
| /** |
| * Calls close() on all SpanReceivers created by this HBaseSpanReceiverHost. |
| */ |
| public synchronized void closeReceivers() { |
| if (closed) return; |
| closed = true; |
| for (SpanReceiver rcvr : receivers) { |
| try { |
| rcvr.close(); |
| } catch (IOException e) { |
| LOG.warn("Unable to close SpanReceiver correctly: " + e.getMessage(), e); |
| } |
| } |
| } |
| } |