org.apache.hadoop.ha.StreamPumper 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.ha;
import org.slf4j.Logger;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
/**
* Class responsible for pumping the streams of the subprocess
* out to log4j. stderr is pumped to WARN level and stdout is
* pumped to INFO level
*/
class StreamPumper {
enum StreamType {
STDOUT, STDERR;
}
private final Logger log;
final Thread thread;
final String logPrefix;
final StreamPumper.StreamType type;
private final InputStream stream;
private boolean started = false;
StreamPumper(final Logger log, final String logPrefix,
final InputStream stream, final StreamType type) {
this.log = log;
this.logPrefix = logPrefix;
this.stream = stream;
this.type = type;
thread = new Thread(new Runnable() {
@Override
public void run() {
try {
pump();
} catch (Throwable t) {
ShellCommandFencer.LOG.warn(logPrefix +
": Unable to pump output from " + type,
t);
}
}
}, logPrefix + ": StreamPumper for " + type);
thread.setDaemon(true);
}
void join() throws InterruptedException {
assert started;
thread.join();
}
void start() {
assert !started;
thread.start();
started = true;
}
protected void pump() throws IOException {
InputStreamReader inputStreamReader = new InputStreamReader(
stream, StandardCharsets.UTF_8);
BufferedReader br = new BufferedReader(inputStreamReader);
String line = null;
while ((line = br.readLine()) != null) {
if (type == StreamType.STDOUT) {
log.info(logPrefix + ": " + line);
} else {
log.warn(logPrefix + ": " + line);
}
}
}
}