org.apache.flink.runtime.util.StdOutErrRedirector 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.flink.runtime.util;
import org.apache.flink.annotation.VisibleForTesting;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.PrintStream;
/**
* Redirect std out and std err to logger.
*/
public class StdOutErrRedirector {
public static final String STDOUT_FILE_PROPERTY_KEY = "stdout.file";
public static final String STDERR_FILE_PROPERTY_KEY = "stderr.file";
private static final String STDOUT_LOGGER_NAME = "StdOutErrRedirector.Stdout";
private static final String STDERR_LOGGER_NAME = "StdOutErrRedirector.Stderr";
private static final Logger stdoutLogger = LoggerFactory.getLogger(STDOUT_LOGGER_NAME);
private static final Logger stderrLogger = LoggerFactory.getLogger(STDERR_LOGGER_NAME);
private static final ThreadLocal isRedirecting = ThreadLocal.withInitial(() -> false);
/**
* Try to redirect stdout and stderr.
*/
public static void redirectStdOutErr() {
if (System.getProperty(STDOUT_FILE_PROPERTY_KEY) != null) {
System.setOut(createLoggerProxy(stdoutLogger, System.out));
}
if (System.getProperty(STDERR_FILE_PROPERTY_KEY) != null) {
System.setErr(createLoggerProxy(stderrLogger, System.err));
}
}
/**
* Create logger proxy print stream.
* Do not check null, keep the same behavior with System.out/err.
*
* @param logger the logger
* @param originalPrintStream the original print stream
* @return the proxy print stream
*/
@VisibleForTesting
static PrintStream createLoggerProxy(final Logger logger, final PrintStream originalPrintStream) {
return new PrintStream(originalPrintStream) {
@Override
public void print(boolean b) {
print(b ? "true" : "false");
}
@Override
public void print(char c) {
print(String.valueOf(c));
}
@Override
public void print(int i) {
print(String.valueOf(i));
}
@Override
public void print(long l) {
print(String.valueOf(l));
}
@Override
public void print(float f) {
print(String.valueOf(f));
}
@Override
public void print(double d) {
print(String.valueOf(d));
}
@Override
public void print(char[] s) {
print(new String(s));
}
@Override
public void print(String s) {
// if it is already redirecting, use original print stream to prevent recursive call
if (!isRedirecting.get()) {
try {
isRedirecting.set(true);
logger.info(s);
} finally {
isRedirecting.set(false);
}
} else {
originalPrintStream.print(s);
}
}
@Override
public void print(Object obj) {
print(String.valueOf(obj));
}
void newLine() {
print(System.lineSeparator());
}
@Override
public void println() {
newLine();
}
@Override
public void println(boolean b) {
print(b);
newLine();
}
@Override
public void println(char c) {
print(c);
newLine();
}
@Override
public void println(int i) {
print(i);
newLine();
}
@Override
public void println(long l) {
print(l);
newLine();
}
@Override
public void println(float f) {
print(f);
newLine();
}
@Override
public void println(double d) {
print(d);
newLine();
}
@Override
public void println(char[] s) {
print(s);
newLine();
}
@Override
public void println(String s) {
print(s);
newLine();
}
@Override
public void println(Object obj) {
print(obj);
newLine();
}
@Override
public PrintStream append(CharSequence csq, int start, int end) {
CharSequence cs = (csq == null ? "null" : csq);
print(cs.subSequence(start, end).toString());
return this;
}
};
}
@VisibleForTesting
static boolean isRedirecting() {
return isRedirecting.get();
}
}