/**
* 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.hadoop.tracing;
import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.tracing.SpanReceiverInfo.ConfigurationPair;
import org.apache.hadoop.util.ShutdownHookManager;
import org.apache.htrace.SpanReceiver;
import org.apache.htrace.SpanReceiverBuilder;
import org.apache.htrace.Trace;
import org.apache.htrace.impl.LocalFileSpanReceiver;
/**
* This class provides functions for reading the names of SpanReceivers from
* the Hadoop configuration, adding those SpanReceivers to the Tracer,
* and closing those SpanReceivers when appropriate.
* This class does nothing If no SpanReceiver is configured.
*/
@InterfaceAudience.Private
public class SpanReceiverHost implements TraceAdminProtocol {
public static final String SPAN_RECEIVERS_CONF_SUFFIX =
"spanreceiver.classes";
private static final Log LOG = LogFactory.getLog(SpanReceiverHost.class);
private static final HashMap<String, SpanReceiverHost> hosts =
new HashMap<String, SpanReceiverHost>(1);
private final TreeMap<Long, SpanReceiver> receivers =
new TreeMap<Long, SpanReceiver>();
private final String confPrefix;
private Configuration config;
private boolean closed = false;
private long highestId = 1;
private final static String LOCAL_FILE_SPAN_RECEIVER_PATH_SUFFIX =
"local-file-span-receiver.path";
public static SpanReceiverHost get(Configuration conf, String confPrefix) {
synchronized (SpanReceiverHost.class) {
SpanReceiverHost host = hosts.get(confPrefix);
if (host != null) {
return host;
}
final SpanReceiverHost newHost = new SpanReceiverHost(confPrefix);
newHost.loadSpanReceivers(conf);
ShutdownHookManager.get().addShutdownHook(new Runnable() {
public void run() {
newHost.closeReceivers();
}
}, 0);
hosts.put(confPrefix, newHost);
return newHost;
}
}
private static List<ConfigurationPair> EMPTY = Collections.emptyList();
private SpanReceiverHost(String confPrefix) {
this.confPrefix = confPrefix;
}
/**
* Reads the names of classes specified in the
* "hadoop.htrace.spanreceiver.classes" property and instantiates and registers
* them with the Tracer as SpanReceiver's.
*
* The nullary constructor is called during construction, but if the classes
* specified implement the Configurable interface, setConfiguration() will be
* called on them. This allows SpanReceivers to use values from the Hadoop
* configuration.
*/
public synchronized void loadSpanReceivers(Configuration conf) {
config = new Configuration(conf);
String receiverKey = confPrefix + SPAN_RECEIVERS_CONF_SUFFIX;
String[] receiverNames = config.getTrimmedStrings(receiverKey);
if (receiverNames == null || receiverNames.length == 0) {
if (LOG.isTraceEnabled()) {
LOG.trace("No span receiver names found in " + receiverKey + ".");
}
return;
}
// It's convenient to have each daemon log to a random trace file when
// testing.
String pathKey = confPrefix + LOCAL_FILE_SPAN_RECEIVER_PATH_SUFFIX;
if (config.get(pathKey) == null) {
String uniqueFile = LocalFileSpanReceiver.getUniqueLocalTraceFileName();
config.set(pathKey, uniqueFile);
if (LOG.isTraceEnabled()) {
LOG.trace("Set " + pathKey + " to " + uniqueFile);
}
}
for (String className : receiverNames) {
try {
SpanReceiver rcvr = loadInstance(className, EMPTY);
Trace.addReceiver(rcvr);
receivers.put(highestId++, rcvr);
LOG.info("Loaded SpanReceiver " + className + " successfully.");
} catch (IOException e) {
LOG.error("Failed to load SpanReceiver", e);
}
}
}
private synchronized SpanReceiver loadInstance(String className,
List<ConfigurationPair> extraConfig) throws IOException {
SpanReceiverBuilder builder =
new SpanReceiverBuilder(TraceUtils.
wrapHadoopConf(confPrefix, config, extraConfig));
SpanReceiver rcvr = builder.spanReceiverClass(className.trim()).build();
if (rcvr == null) {
throw new IOException("Failed to load SpanReceiver " + className);
}
return rcvr;
}
/**
* Calls close() on all SpanReceivers created by this SpanReceiverHost.
*/
public synchronized void closeReceivers() {
if (closed) return;
closed = true;
for (SpanReceiver rcvr : receivers.values()) {
try {
rcvr.close();
} catch (IOException e) {
LOG.warn("Unable to close SpanReceiver correctly: " + e.getMessage(), e);
}
}
receivers.clear();
}
public synchronized SpanReceiverInfo[] listSpanReceivers()
throws IOException {
SpanReceiverInfo[] info = new SpanReceiverInfo[receivers.size()];
int i = 0;
for(Map.Entry<Long, SpanReceiver> entry : receivers.entrySet()) {
info[i] = new SpanReceiverInfo(entry.getKey(),
entry.getValue().getClass().getName());
i++;
}
return info;
}
public synchronized long addSpanReceiver(SpanReceiverInfo info)
throws IOException {
StringBuilder configStringBuilder = new StringBuilder();
String prefix = "";
for (ConfigurationPair pair : info.configPairs) {
configStringBuilder.append(prefix).append(pair.getKey()).
append(" = ").append(pair.getValue());
prefix = ", ";
}
SpanReceiver rcvr = null;
try {
rcvr = loadInstance(info.getClassName(), info.configPairs);
} catch (IOException e) {
LOG.info("Failed to add SpanReceiver " + info.getClassName() +
" with configuration " + configStringBuilder.toString(), e);
throw e;
} catch (RuntimeException e) {
LOG.info("Failed to add SpanReceiver " + info.getClassName() +
" with configuration " + configStringBuilder.toString(), e);
throw e;
}
Trace.addReceiver(rcvr);
long newId = highestId++;
receivers.put(newId, rcvr);
LOG.info("Successfully added SpanReceiver " + info.getClassName() +
" with configuration " + configStringBuilder.toString());
return newId;
}
public synchronized void removeSpanReceiver(long spanReceiverId)
throws IOException {
SpanReceiver rcvr = receivers.remove(spanReceiverId);
if (rcvr == null) {
throw new IOException("There is no span receiver with id " + spanReceiverId);
}
Trace.removeReceiver(rcvr);
rcvr.close();
LOG.info("Successfully removed SpanReceiver " + spanReceiverId +
" with class " + rcvr.getClass().getName());
}
}