org.apache.log4j.varia.ExternallyRolledFileAppender 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.log4j.varia;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.ServerSocket;
import java.net.Socket;
import org.apache.log4j.RollingFileAppender;
import org.apache.log4j.helpers.LogLog;
/**
This appender listens on a socket on the port specified by the
Port property for a "RollOver" message. When such a message
is received, the underlying log file is rolled over and an
acknowledgment message is sent back to the process initiating the
roll over.
This method of triggering roll over has the advantage of being
operating system independent, fast and reliable.
A simple application {@link Roller} is provided to initiate the
roll over.
Note that the initiator is not authenticated. Anyone can trigger
a rollover. In production environments, it is recommended that you
add some form of protection to prevent undesired rollovers.
@author Ceki Gülcü
@since version 0.9.0 */
public class ExternallyRolledFileAppender extends RollingFileAppender {
/**
The string constant sent to initiate a roll over. Current value of
this string constant is RollOver.
*/
static final public String ROLL_OVER = "RollOver";
/**
The string constant sent to acknowledge a roll over. Current value of
this string constant is OK.
*/
static final public String OK = "OK";
int port = 0;
HUP hup;
/**
The default constructor does nothing but calls its super-class
constructor. */
public
ExternallyRolledFileAppender() {
}
/**
The Port [roperty is used for setting the port for
listening to external roll over messages.
*/
public
void setPort(int port) {
this.port = port;
}
/**
Returns value of the Port option.
*/
public
int getPort() {
return port;
}
/**
Start listening on the port specified by a preceding call to
{@link #setPort}. */
public
void activateOptions() {
super.activateOptions();
if(port != 0) {
if(hup != null) {
hup.interrupt();
}
hup = new HUP(this, port);
hup.setDaemon(true);
hup.start();
}
}
}
class HUP extends Thread {
int port;
ExternallyRolledFileAppender er;
HUP(ExternallyRolledFileAppender er, int port) {
this.er = er;
this.port = port;
}
public
void run() {
while(!isInterrupted()) {
try {
ServerSocket serverSocket = new ServerSocket(port);
while(true) {
Socket socket = serverSocket.accept();
LogLog.debug("Connected to client at " + socket.getInetAddress());
new Thread(new HUPNode(socket, er), "ExternallyRolledFileAppender-HUP").start();
}
} catch(InterruptedIOException e) {
Thread.currentThread().interrupt();
e.printStackTrace();
} catch(IOException e) {
e.printStackTrace();
} catch(RuntimeException e) {
e.printStackTrace();
}
}
}
}
class HUPNode implements Runnable {
Socket socket;
DataInputStream dis;
DataOutputStream dos;
ExternallyRolledFileAppender er;
public
HUPNode(Socket socket, ExternallyRolledFileAppender er) {
this.socket = socket;
this.er = er;
try {
dis = new DataInputStream(socket.getInputStream());
dos = new DataOutputStream(socket.getOutputStream());
} catch(InterruptedIOException e) {
Thread.currentThread().interrupt();
e.printStackTrace();
} catch(IOException e) {
e.printStackTrace();
} catch(RuntimeException e) {
e.printStackTrace();
}
}
public void run() {
try {
String line = dis.readUTF();
LogLog.debug("Got external roll over signal.");
if(ExternallyRolledFileAppender.ROLL_OVER.equals(line)) {
synchronized(er) {
er.rollOver();
}
dos.writeUTF(ExternallyRolledFileAppender.OK);
}
else {
dos.writeUTF("Expecting [RollOver] string.");
}
dos.close();
} catch(InterruptedIOException e) {
Thread.currentThread().interrupt();
LogLog.error("Unexpected exception. Exiting HUPNode.", e);
} catch(IOException e) {
LogLog.error("Unexpected exception. Exiting HUPNode.", e);
} catch(RuntimeException e) {
LogLog.error("Unexpected exception. Exiting HUPNode.", e);
}
}
}