/*
* Copyright 1999,2004 The Apache Software Foundation.
*
* Licensed 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.chainsaw.vfs;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import org.apache.commons.vfs.FileObject;
import org.apache.commons.vfs.FileSystemException;
import org.apache.commons.vfs.FileSystemManager;
import org.apache.commons.vfs.VFS;
import org.apache.log4j.varia.LogFilePatternReceiver;
/**
* A VFS-enabled version of org.apache.log4j.varia.LogFilePatternReceiver.
*
* VFSLogFilePatternReceiver can parse and tail log files, converting entries into
* LoggingEvents. If the file doesn't exist when the receiver is initialized, the
* receiver will look for the file once every 10 seconds.
* <p>
* This receiver relies on ORO Perl5 features to perform the parsing of text in the
* log file, however the only regular expression field explicitly supported is
* a glob-style wildcard used to ignore fields in the log file if needed. All other
* fields are parsed by using the supplied keywords.
* <p>
* <b>Features:</b><br>
* - specify the URL of the log file to be processed<br>
* - specify the timestamp format in the file (if one exists)<br>
* - specify the pattern (logFormat) used in the log file using keywords, a wildcard character (*) and fixed text<br>
* - 'tail' the file (allows the contents of the file to be continually read and new events processed)<br>
* - supports the parsing of multi-line messages and exceptions
*<p>
* <b>Keywords:</b><br>
* TIMESTAMP<br>
* LOGGER<br>
* LEVEL<br>
* THREAD<br>
* CLASS<br>
* FILE<br>
* LINE<br>
* METHOD<br>
* RELATIVETIME<br>
* MESSAGE<br>
* NDC<br>
* PROP(key)<br>
* <p>
* Use a * to ignore portions of the log format that should be ignored
* <p>
* Example:<br>
* If your file's patternlayout is this:<br>
* <b>%d %-5p [%t] %C{2} (%F:%L) - %m%n</b>
*<p>
* specify this as the log format:<br>
* <b>TIMESTAMP LEVEL [THREAD] CLASS (FILE:LINE) - MESSAGE</b>
*<p>
* To define a PROPERTY field, use PROP(key)
* <p>
* Example:<br>
* If you used the RELATIVETIME pattern layout character in the file,
* you can use PROP(RELATIVETIME) in the logFormat definition to assign
* the RELATIVETIME field as a property on the event.
* <p>
* If your file's patternlayout is this:<br>
* <b>%r [%t] %-5p %c %x - %m%n</b>
*<p>
* specify this as the log format:<br>
* <b>PROP(RELATIVETIME) [THREAD] LEVEL LOGGER * - MESSAGE</b>
* <p>
* Note the * - it can be used to ignore a single word or sequence of words in the log file
* (in order for the wildcard to ignore a sequence of words, the text being ignored must be
* followed by some delimiter, like '-' or '[') - ndc is being ignored in this example.
* <p>
* Assign a filterExpression in order to only process events which match a filter.
* If a filterExpression is not assigned, all events are processed.
*<p>
* <b>Limitations:</b><br>
* - no support for the single-line version of throwable supported by patternlayout<br>
* (this version of throwable will be included as the last line of the message)<br>
* - the relativetime patternLayout character must be set as a property: PROP(RELATIVETIME)<br>
* - messages should appear as the last field of the logFormat because the variability in message content<br>
* - exceptions are converted if the exception stack trace (other than the first line of the exception)<br>
* is stored in the log file with a tab followed by the word 'at' as the first characters in the line<br>
* - tailing may fail if the file rolls over.
*<p>
* <b>Example receiver configuration settings</b> (add these as params, specifying a LogFilePatternReceiver 'plugin'):<br>
* param: "timestampFormat" value="yyyy-MM-d HH:mm:ss,SSS"<br>
* param: "logFormat" value="RELATIVETIME [THREAD] LEVEL LOGGER * - MESSAGE"<br>
* param: "fileURL" value="file:///c:/events.log"<br>
* param: "tailing" value="true"
*<p>
* This configuration will be able to process these sample events:<br>
* 710 [ Thread-0] DEBUG first.logger first - <test> <test2>something here</test2> <test3 blah=something/> <test4> <test5>something else</test5> </test4></test><br>
* 880 [ Thread-2] DEBUG first.logger third - <test> <test2>something here</test2> <test3 blah=something/> <test4> <test5>something else</test5> </test4></test><br>
* 880 [ Thread-0] INFO first.logger first - infomsg-0<br>
* java.lang.Exception: someexception-first<br>
* at Generator2.run(Generator2.java:102)<br>
*
*@author Scott Deboy
*/
public class VFSLogFilePatternReceiver extends LogFilePatternReceiver {
private Reader reader;
public VFSLogFilePatternReceiver() {
super();
}
public void shutdown() {
if (reader != null) {
try {
reader.close();
reader = null;
} catch (IOException ioe) {
getLogger().warn("Unable to close reader", ioe);
}
}
}
/**
* Read and process the log file.
*/
public void activateOptions() {
new Thread(new Runnable() {
public void run() {
initialize();
while (reader == null) {
getLogger().info("attempting to load file: " + getFileURL());
try {
FileSystemManager fileSystemManager = VFS.getManager();
FileObject fileObject = fileSystemManager.resolveFile(getFileURL());
reader = new InputStreamReader(fileObject.getContent().getInputStream());
} catch (FileSystemException fse) {
getLogger().info("file not available - will try again in 10 seconds");
synchronized(this) {
try {
wait(10000);
} catch (InterruptedException ie){}
}
}
}
try {
process(reader);
} catch (IOException ioe) {
getLogger().info("stream closed");
}
}}).start();
}
}