org.apache.hadoop.fs.FsTracer Maven / Gradle / Ivy
/**
* 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.fs;
import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.tracing.TraceUtils;
import org.apache.htrace.core.Tracer;
/**
* Holds the HTrace Tracer used for FileSystem operations.
*
* Ideally, this would be owned by the DFSClient, rather than global. However,
* the FileContext API may create a new DFSClient for each operation in some
* cases. Because of this, we cannot store this Tracer inside DFSClient. See
* HADOOP-6356 for details.
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public final class FsTracer {
private static Tracer instance;
public static synchronized Tracer get(Configuration conf) {
if (instance == null) {
instance = new Tracer.Builder("FSClient").
conf(TraceUtils.wrapHadoopConf(CommonConfigurationKeys.
FS_CLIENT_HTRACE_PREFIX, conf)).
build();
}
return instance;
}
@VisibleForTesting
public static synchronized void clear() {
if (instance == null) {
return;
}
try {
instance.close();
} finally {
instance = null;
}
}
private FsTracer() {
}
}