/*
* 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.karaf.shell.log;
import java.io.IOException;
import java.io.PrintStream;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;
import org.apache.felix.gogo.commands.Command;
import org.apache.karaf.shell.log.layout.PatternConverter;
import org.apache.karaf.shell.log.layout.PatternParser;
import org.ops4j.pax.logging.spi.PaxAppender;
import org.ops4j.pax.logging.spi.PaxLoggingEvent;
@Command(scope = "log", name = "tail", description = "Continuously display log entries. Use ctrl-c to quit this command")
public class LogTail extends DisplayLog {
private ExecutorService executorService = Executors.newSingleThreadExecutor();
protected Object doExecute() throws Exception {
PrintEventThread printThread = new PrintEventThread();
executorService.execute(printThread);
new Thread(new ReadKeyBoardThread(this, Thread.currentThread())).start();
while (!Thread.currentThread().isInterrupted());
printThread.abort();
executorService.shutdownNow();
return null;
}
class ReadKeyBoardThread implements Runnable {
private LogTail logTail;
private Thread sessionThread;
public ReadKeyBoardThread(LogTail logtail, Thread thread) {
this.logTail = logtail;
this.sessionThread = thread;
}
public void run() {
for (;;) {
try {
int c = this.logTail.session.getKeyboard().read();
if (c < 0) {
this.sessionThread.interrupt();
break;
}
} catch (IOException e) {
break;
}
}
}
}
class PrintEventThread implements Runnable {
boolean doDisplay = true;
public void run() {
final PatternConverter cnv = new PatternParser(overridenPattern != null ? overridenPattern : pattern).parse();
final PrintStream out = System.out;
Iterable<PaxLoggingEvent> le = events.getElements(entries == 0 ? Integer.MAX_VALUE : entries);
for (PaxLoggingEvent event : le) {
display(cnv, event, out);
}
// Tail
final BlockingQueue<PaxLoggingEvent> queue = new LinkedBlockingQueue<PaxLoggingEvent>();
PaxAppender appender = new PaxAppender() {
public void doAppend(PaxLoggingEvent event) {
queue.add(event);
}
};
try {
events.addAppender(appender);
while (doDisplay) {
PaxLoggingEvent logEvent = queue.take();
if (logEvent != null) {
display(cnv, logEvent, out);
}
}
} catch (InterruptedException e) {
// Ignore
} finally {
events.removeAppender(appender);
}
out.println();
}
public void abort() {
doDisplay = false;
}
}
}