Ec2Server.java

/*
 * Copyright 2008-2012 Amazon Technologies, Inc.
 *
 * 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://aws.amazon.com/apache2.0
 *
 * This file 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 com.amazonaws.ec2.cluster;

import java.io.File;

import com.amazonaws.AmazonClientException;
import com.amazonaws.eclipse.ec2.InstanceUtils;
import com.amazonaws.services.ec2.AmazonEC2;
import com.amazonaws.services.ec2.model.Instance;

/**
 * Represents an individual server/host running in EC2.  This class
 * is not intended to be used directly and should be subclasses by
 * clients instead.
 */
public abstract class Ec2Server {

	/** The EC2 instance running this server */
	protected Instance instance;

	/** True if this server is (or should be) in debug mode */
	private boolean debugMode;

	/**
	 * Creates a new Ec2Server associated with the specified EC2 instance.
	 *
	 * @param instance
	 *            The EC2 instance associated with this Ec2Server.
	 */
	public Ec2Server(Instance instance) {
		this.instance = instance;
	}

	/**
	 * Optional method that application server subclasses can implement to
	 * perform additional server initialization. Subclasses who do chose to
	 * implement this should be aware that they are responsible for detecting if
	 * initializing is necessary or not inside their implementation. The
	 * framework will call this during each launch.
	 *
	 * @throws Exception
	 *             If there were any problems while initializing this
	 *             application server.
	 */
	public void initialize() throws Exception {}

	/**
	 * Subclasses of Ec2Server must implement this method with the specific code
	 * required to start their server application on the EC2 instance associated
	 * with this server object.
	 *
	 * @throws Exception
	 *             If any problems are encountered while starting the
	 *             application server on this EC2 instance.
	 */
	public abstract void stop() throws Exception;

	/**
	 * Subclasses of Ec2Server must implement this method with the specific code
	 * required to stop their server application on the EC2 instance associated
	 * with this server object.
	 *
	 * @throws Exception
	 *             If any problems are encountered while starting the
	 *             application server on this EC2 instance.
	 */
	public abstract void start() throws Exception;

	/**
	 * Publishes the archive file (containing the project resources that the EC2
	 * cluster management layer determined needed to be published) for the
	 * project associated with the specified module to this host.
	 *
	 * @param archiveFile
	 *            An archive file containing the project resources that need to
	 *            be published. This is not necessarily the entire project, but
	 *            just what the EC2 cluster management layer thinks needs to be
	 *            published to this host, based on its knowledge of prior
	 *            publish events.
	 * @param moduleName
	 *            The name of the module associated with the project being
	 *            published.
	 *
	 * @throws Exception
	 *             If any problems are encountered while publishing.
	 */
	public abstract void publish(File archiveFile, String moduleName) throws Exception;

	/**
	 * Publishes the server configuration files for this host.
	 *
	 * @param serverConfigurationDirectory
	 *            The directory containing the server configuration files that need
	 *            to be published to this server.
	 *
	 * @throws Exception
	 *             If any problems are encountered while publishing.
	 */
	public abstract void publishServerConfiguration(File serverConfigurationDirectory) throws Exception;

	/**
	 * Sets whether or not this server should be running in debug mode.
	 *
	 * @param debugMode
	 *            True if this server should be running in debug mode.
	 */
	public void setDebugMode(boolean debugMode) {
		this.debugMode = debugMode;
	}

	/**
	 * Returns whether or not this server is (or should be) running in debug
	 * mode.
	 *
	 * @return True if this server should be running in debug mode.
	 */
	public boolean isDebugMode() {
		return debugMode;
	}

	/**
	 * Reloads the data about the EC2 instance represented by this server.
	 *
	 * @param ec2Client
	 *            The EC2 client to use when refreshing the instance data.
	 * @throws AmazonClientException
	 *             If any problems are encountered refreshing the instance data.
	 */
	public void refreshInstance(AmazonEC2 ec2Client) throws AmazonClientException {
		InstanceUtils instanceUtils = new InstanceUtils(ec2Client);

		Instance tempInstance = instanceUtils.lookupInstanceById(getInstanceId());

		if (tempInstance == null) {
			throw new AmazonClientException(
				"Unable to find a running instance with id: " + getInstanceId());
		}

		instance = tempInstance;
	}

	/**
	 * Returns the IP address of this host.
	 *
	 * @return The IP address of this host.
	 */
	public String getIp() {
		return instance.getPublicDnsName();
	}

	/**
	 * Returns the ID of the Amazon EC2 instance this server represents.
	 *
	 * @return The ID of the Amazon EC2 instance this server represents.
	 */
	public String getInstanceId() {
		return instance.getInstanceId();
	}

	/**
	 * Returns the Amazon EC2 instance this server represents.
	 *
	 * @return The Amazon EC2 instance this server represents.
	 */
	public Instance getInstance() {
		return instance;
	}

}