org.eclipse.jetty.server.StateLifeCycleListener Maven / Gradle / Ivy
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//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
package org.eclipse.jetty.server;
import java.io.IOException;
import java.io.Writer;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import org.eclipse.jetty.util.component.LifeCycle;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static java.nio.charset.StandardCharsets.UTF_8;
import static java.nio.file.StandardOpenOption.APPEND;
import static java.nio.file.StandardOpenOption.CREATE_NEW;
import static java.nio.file.StandardOpenOption.WRITE;
/**
* A LifeCycle Listener that writes state changes to a file.
* This can be used with the jetty.sh script to wait for successful startup.
*/
public class StateLifeCycleListener implements LifeCycle.Listener
{
private static final Logger LOG = LoggerFactory.getLogger(StateLifeCycleListener.class);
private final Path stateFile;
public StateLifeCycleListener(String filename) throws IOException
{
stateFile = Paths.get(filename).toAbsolutePath();
if (LOG.isDebugEnabled())
LOG.debug("State File: {}", stateFile);
// We use raw Files APIs here to allow important IOExceptions
// to fail the startup of Jetty, as these kinds of errors
// point to filesystem permission issues that must be resolved
// by the user before the state file can be used.
// Start with fresh file (for permission reasons)
Files.deleteIfExists(stateFile);
// Create file
Files.writeString(stateFile, "INIT " + this + "\n", UTF_8, WRITE, CREATE_NEW);
}
private void appendStateChange(String action, Object obj)
{
try (Writer out = Files.newBufferedWriter(stateFile, UTF_8, WRITE, APPEND))
{
String entry = String.format("%s %s\n", action, obj);
if (LOG.isDebugEnabled())
LOG.debug("appendEntry to {}: {}", stateFile, entry);
out.append(entry);
}
catch (IOException e)
{
// this can happen if the uid of the Jetty process changes after it has been started
// such as can happen with some setuid configurations
LOG.warn("Unable to append to state file: " + stateFile, e);
}
}
@Override
public void lifeCycleStarting(LifeCycle event)
{
appendStateChange("STARTING", event);
}
@Override
public void lifeCycleStarted(LifeCycle event)
{
appendStateChange("STARTED", event);
}
@Override
public void lifeCycleFailure(LifeCycle event, Throwable cause)
{
appendStateChange("FAILED", event);
}
@Override
public void lifeCycleStopping(LifeCycle event)
{
appendStateChange("STOPPING", event);
}
@Override
public void lifeCycleStopped(LifeCycle event)
{
appendStateChange("STOPPED", event);
}
@Override
public String toString()
{
return String.format("%s@%h", this.getClass().getSimpleName(), this);
}
}