org.eclipse.gyrex.cloud.internal.zk.ZooKeeperPinger.java Source code

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Here is the source code for org.eclipse.gyrex.cloud.internal.zk.ZooKeeperPinger.java

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/*******************************************************************************
 * Copyright (c) 2011, 2012 AGETO Service GmbH and others.
 * All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html.
 *
 * Contributors:
 *     Gunnar Wagenknecht - initial API and implementation
 *******************************************************************************/
package org.eclipse.gyrex.cloud.internal.zk;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import org.eclipse.gyrex.cloud.internal.CloudActivator;
import org.eclipse.gyrex.cloud.internal.CloudDebug;
import org.eclipse.gyrex.monitoring.diagnostics.IStatusConstants;

import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;

import org.osgi.framework.ServiceRegistration;

import org.apache.commons.lang.exception.ExceptionUtils;
import org.apache.commons.lang.time.DateFormatUtils;
import org.apache.zookeeper.CreateMode;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A simple runnable to ping ZooKeeper
 */
public final class ZooKeeperPinger implements Runnable {

    private static final Logger LOG = LoggerFactory.getLogger(ZooKeeperPinger.class);
    private static final String STATUS_PID = CloudActivator.SYMBOLIC_NAME + ".status.zookeeper.connection";
    private static final Callable<IStatus> checkConnection = new Callable<IStatus>() {

        @Override
        public IStatus call() throws Exception {
            final ZooKeeperGate zk = ZooKeeperGate.get();
            final IPath pingPath = zk.createPath(IZooKeeperLayout.PATH_GYREX_ROOT.append("ping"),
                    CreateMode.EPHEMERAL_SEQUENTIAL,
                    DateFormatUtils.ISO_DATETIME_TIME_ZONE_FORMAT.format(System.currentTimeMillis()));
            zk.deletePath(pingPath);
            return null;
        }
    };
    private ServiceRegistration serviceRegistration;

    @Override
    public void run() {
        final ExecutorService executor = Executors.newSingleThreadExecutor();
        try {
            if (CloudDebug.zooKeeperGateLifecycle) {
                LOG.debug("Checking ZooKeeper connection...");
            }

            // execute in separate thread with timeout
            executor.submit(checkConnection).get(30, TimeUnit.SECONDS);

            if (CloudDebug.zooKeeperGateLifecycle) {
                LOG.debug("ZooKeeper connection OK");
            }

            // ok
            setStatus(null);
        } catch (final Exception e) {
            LOG.error("The ZooKeeper connection is in trouble. {}", ExceptionUtils.getRootCauseMessage(e), e);
            setStatus(new Status(IStatus.ERROR, CloudActivator.SYMBOLIC_NAME,
                    String.format("Unable to ping ZooKeeper. %s", ExceptionUtils.getRootCauseMessage(e)), e));
        } finally {
            executor.shutdownNow();
        }
    }

    private synchronized void setStatus(final IStatus status) {
        try {
            if (null != serviceRegistration) {
                serviceRegistration.unregister();
                serviceRegistration = null;
            }
            if ((null != status) && !status.isOK()) {
                serviceRegistration = CloudActivator.getInstance().getServiceHelper().registerService(
                        IStatusConstants.SERVICE_NAME, status, "Eclipse Gyrex", "ZooKeeper Connection Status",
                        STATUS_PID, null);
            }
        } catch (final IllegalStateException e) {
            LOG.warn("Unable to update ZooKeeper connection status. {}", e.getMessage());
        }
    }
}