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Posted to log4j-cvs@jakarta.apache.org by ce...@apache.org on 2002/03/25 23:05:36 UTC
cvs commit: jakarta-log4j/src/java/org/apache/log4j/net SocketHubAppender.java
ceki 02/03/25 14:05:36
Modified: src/java/org/apache/log4j/jdbc JDBCAppender.java
Added: src/java/org/apache/log4j/net SocketHubAppender.java
Log:
Added SocketHubAppender as supplied by Mark Womack.
Renamed the package of JDBCAppender
Revision Changes Path
1.2 +1 -1 jakarta-log4j/src/java/org/apache/log4j/jdbc/JDBCAppender.java
Index: JDBCAppender.java
===================================================================
RCS file: /home/cvs/jakarta-log4j/src/java/org/apache/log4j/jdbc/JDBCAppender.java,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -r1.1 -r1.2
--- JDBCAppender.java 25 Mar 2002 21:57:57 -0000 1.1
+++ JDBCAppender.java 25 Mar 2002 22:05:36 -0000 1.2
@@ -1,4 +1,4 @@
-package org.apache.log4j;
+package org.apache.log4j.jdbc;
import org.apache.log4j.*;
import org.apache.log4j.spi.*;
1.1 jakarta-log4j/src/java/org/apache/log4j/net/SocketHubAppender.java
Index: SocketHubAppender.java
===================================================================
/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software License
* version 1.1, a copy of which has been included with this distribution in
* the LICENSE file.
*/
package org.apache.log4j.net;
import java.util.Vector;
import java.net.Socket;
import java.net.ServerSocket;
import java.net.SocketException;
import java.io.ObjectOutputStream;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.InetAddress;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.AppenderSkeleton;
/**
Sends {@link LoggingEvent} objects to a set remote a log servers,
usually a {@link SocketNode}.
Acts just like {@link SocketAppender} except that instead of
connecting to a given remote log server, SocketHubAppender
accepts connections from the remote log servers as clients. It
can accept more than one connection, and when a log event is
handled, the event is sent to the set of currently connected
remote log servers. Implemented this way it does not require any
update to the configuration file to send data to another remote
log server. The remote log server simple connects to the host and
port the SocketHubAppender is running on.
However, given the nature of accepting connections on-the-fly, it
cannot be guaranteed that all events will be received while the
tcp connection is in process. But once connected, it should behave
the same as {@link SocketAppender}.
This implementation borrows heavily from the {@link SocketAppender}
implementation as an example.
<p>The SocketHubAppender has the following properties:
<ul>
<p><li>If sent to a {@link SocketNode}, remote logging is
non-intrusive as far as the log event is concerned. In other
words, the event will be logged with the same time stamp, {@link
org.apache.log4j.NDC}, location info as if it were logged locally by
the client.
<p><li>SocketHubAppenders do not use a layout. They ship a
serialized {@link LoggingEvent} object to the server side.
<p><li>Remote logging uses the TCP protocol. Consequently, if
the server is reachable, then log events will eventually arrive
at the server.
<p><li>If no remote servers are attached, the logging requests are
simply dropped.
<p><li>Logging events are automatically <em>buffered</em> by the
native TCP implementation. This means that if the link to server
is slow but still faster than the rate of (log) event production
by the client, the client will not be affected by the slow
network connection. However, if the network connection is slower
then the rate of event production, then the client can only
progress at the network rate. In particular, if the network link
to the the server is down, the client will be blocked.
<p>On the other hand, if the network link is up, but the server
is down, the client will not be blocked when making log requests
but the log events will be lost due to server unavailability.
<p><li>If the JVM hosting the <code>SocketHubAppender</code> exits
before the <code>SocketHubAppender</code> is closed either
explicitly or subsequent to garbage collection, then there might
be untransmitted data in the pipe which might be lost. This is a
common problem on Windows based systems.
<p>To avoid lost data, it is usually sufficient to {@link #close}
the <code>SocketHubAppender</code> either explicitly or by calling
the {@link Category#shutdown} method before exiting the
application.
</ul>
@author Mark Womack
*/
public class SocketHubAppender extends AppenderSkeleton {
/**
The default port number of the ServerSocket will be created on. */
static final int DEFAULT_PORT = 4560;
private int port = DEFAULT_PORT;
private Vector oosList = new Vector();
private ServerMonitor serverMonitor = null;
private boolean locationInfo = false;
public SocketHubAppender() { }
/**
Connects to remote server at <code>address</code> and <code>port</code>. */
public
SocketHubAppender(int _port) {
port = _port;
startServer();
}
/**
Set up the socket server on the specified port. */
public
void activateOptions() {
startServer();
}
/**
Close this appender.
<p>This will mark the appender as closed and
call then {@link #cleanUp} method. */
synchronized
public
void close() {
if(closed)
return;
LogLog.debug("closing SocketHubAppender " + getName());
this.closed = true;
cleanUp();
LogLog.debug("SocketHubAppender " + getName() + " closed");
}
/**
Release the underlying ServerMonitor thread, and drop the connections
to all connected remote servers. */
public
void cleanUp() {
// stop the monitor thread
LogLog.debug("stopping ServerSocket");
serverMonitor.stopMonitor();
serverMonitor = null;
// close all of the connections
LogLog.debug("closing client connections");
while (oosList.size() != 0) {
ObjectOutputStream oos = (ObjectOutputStream)oosList.get(0);
if(oos != null) {
try {
oos.close();
}
catch(IOException e) {
LogLog.error("could not close oos.", e);
}
oosList.remove(0);
}
}
}
/**
Append an event to all of current connections. */
public
void append(LoggingEvent event) {
// if no event or no open connections, exit now
if(event == null || oosList.size() == 0)
return;
// set up location info if requested
if (locationInfo) {
event.getLocationInformation();
}
// loop through the current set of open connections, appending the event to each
for (int streamCount = 0; streamCount < oosList.size(); streamCount++) {
ObjectOutputStream oos = null;
try {
oos = (ObjectOutputStream)oosList.get(streamCount);
}
catch (ArrayIndexOutOfBoundsException e) {
// catch this, but just don't assign a value
// this should not really occur as this method is
// the only one that can remove oos's (besides cleanUp).
}
// list size changed unexpectedly? Just exit the append.
if (oos == null)
break;
try {
oos.writeObject(event);
oos.flush();
// Failing to reset the object output stream every now and
// then creates a serious memory leak.
// right now we always reset. TODO - set up frequency counter per oos?
oos.reset();
}
catch(IOException e) {
// there was an io exception so just drop the connection
oosList.remove(streamCount);
LogLog.debug("dropped connection");
// decrement to keep the counter in place (for loop always increments)
streamCount--;
}
}
}
/**
The SocketHubAppender does not use a layout. Hence, this method returns
<code>false</code>. */
public
boolean requiresLayout() {
return false;
}
/**
The <b>Port</b> option takes a positive integer representing
the port where the server is waiting for connections. */
public
void setPort(int _port) {
port = _port;
}
/**
Returns value of the <b>Port</b> option. */
public
int getPort() {
return port;
}
/**
The <b>LocationInfo</b> option takes a boolean value. If true,
the information sent to the remote host will include location
information. By default no location information is sent to the server. */
public
void setLocationInfo(boolean _locationInfo) {
locationInfo = _locationInfo;
}
/**
Returns value of the <b>LocationInfo</b> option. */
public
boolean getLocationInfo() {
return locationInfo;
}
/**
Start the ServerMonitor thread. */
private
void startServer() {
serverMonitor = new ServerMonitor(port, oosList);
}
/**
This class is used internally to monitor a ServerSocket
and register new connections in a vector passed in the
constructor. */
private
class ServerMonitor implements Runnable {
private int port;
private Vector oosList;
private boolean keepRunning;
private Thread monitorThread;
/**
Create a thread and start the monitor. */
public
ServerMonitor(int _port, Vector _oosList) {
port = _port;
oosList = _oosList;
keepRunning = true;
monitorThread = new Thread(this);
monitorThread.setDaemon(true);
monitorThread.start();
}
/**
Stops the monitor. This method will not return until
the thread has finished executing. */
public
synchronized
void stopMonitor() {
if (keepRunning) {
LogLog.debug("server monitor thread shutting down");
keepRunning = false;
try {
monitorThread.join();
}
catch (InterruptedException e) {
// do nothing?
}
// release the thread
monitorThread = null;
LogLog.debug("server monitor thread shut down");
}
}
/**
Method that runs, monitoring the ServerSocket and adding connections as
they connect to the socket. */
public
void run() {
ServerSocket serverSocket = null;
try {
serverSocket = new ServerSocket(port);
serverSocket.setSoTimeout(1000);
}
catch (Exception e) {
LogLog.error("exception setting timeout, shutting down server socket.", e);
keepRunning = false;
return;
}
try {
try {
serverSocket.setSoTimeout(1000);
}
catch (SocketException e) {
LogLog.error("exception setting timeout, shutting down server socket.", e);
return;
}
while (keepRunning) {
Socket socket = null;
try {
socket = serverSocket.accept();
}
catch (InterruptedIOException e) {
// timeout occurred, so just loop
}
catch (SocketException e) {
LogLog.error("exception accepting socket, shutting down server socket.", e);
keepRunning = false;
}
catch (IOException e) {
LogLog.error("exception accepting socket.", e);
}
// if there was a socket accepted
if (socket != null) {
try {
InetAddress remoteAddress = socket.getInetAddress();
LogLog.debug("accepting connection from " + remoteAddress.getHostName() + " (" + remoteAddress.getHostAddress() + ")");
// create an ObjectOutputStream
ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());
// add it to the oosList. OK since Vector is synchronized.
oosList.add(oos);
}
catch (IOException e) {
LogLog.error("exception creating output stream on socket.", e);
}
}
}
}
finally {
// close the socket
try {
serverSocket.close();
}
catch (IOException e) {
// do nothing with it?
}
}
}
}
}
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