AzkabanServer.java

/*
 * Copyright 2012 LinkedIn Corp.
 * 
 * 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 azkaban.webapp;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Arrays;

import joptsimple.OptionParser;
import joptsimple.OptionSet;
import joptsimple.OptionSpec;

import org.apache.log4j.Logger;
import org.apache.velocity.app.VelocityEngine;

import azkaban.user.UserManager;
import azkaban.utils.Props;
import azkaban.webapp.session.SessionCache;


public abstract class AzkabanServer {
	private static final Logger logger = Logger.getLogger(AzkabanServer.class);
	public static final String AZKABAN_PROPERTIES_FILE = "azkaban.properties";
	public static final String AZKABAN_PRIVATE_PROPERTIES_FILE = "azkaban.private.properties";
	public static final String DEFAULT_CONF_PATH = "conf";
	
	public static Props loadProps(String[] args) {
		return loadProps(args, new OptionParser());
	}
	
	public static Props loadProps(String[] args, OptionParser parser) {;
		OptionSpec<String> configDirectory = parser
				.acceptsAll(Arrays.asList("c", "conf"), "The conf directory for Azkaban.")
				.withRequiredArg()
				.describedAs("conf").ofType(String.class);

		// Grabbing the azkaban settings from the conf directory.
		Props azkabanSettings = null;
		OptionSet options = parser.parse(args);
		
		if (options.has(configDirectory)) {
			String path = options.valueOf(configDirectory);
			logger.info("Loading azkaban settings file from " + path);
			File dir = new File(path);
			if (!dir.exists()) {
				logger.error("Conf directory " + path + " doesn't exist.");
			}
			else if (!dir.isDirectory()) {
				logger.error("Conf directory " + path + " isn't a directory.");
			}
			else {
				azkabanSettings = loadAzkabanConfigurationFromDirectory(dir);
			}
		} 
		else {
			logger.info("Conf parameter not set, attempting to get value from AZKABAN_HOME env.");
			azkabanSettings = loadConfigurationFromAzkabanHome();
		}
		
		return azkabanSettings;
	}

	private static Props loadAzkabanConfigurationFromDirectory(File dir) {
		File azkabanPrivatePropsFile = new File(dir, AZKABAN_PRIVATE_PROPERTIES_FILE);
		File azkabanPropsFile = new File(dir, AZKABAN_PROPERTIES_FILE);
		
		Props props = null;
		try {
			// This is purely optional
			if (azkabanPrivatePropsFile.exists() && azkabanPrivatePropsFile.isFile()) {
				logger.info("Loading azkaban private properties file" );
				props = new Props(null, azkabanPrivatePropsFile);
			}

			if (azkabanPropsFile.exists() && azkabanPropsFile.isFile()) {
				logger.info("Loading azkaban properties file" );
				props = new Props(props, azkabanPropsFile);
			}
		} catch (FileNotFoundException e) {
			logger.error("File not found. Could not load azkaban config file", e);
		} catch (IOException e) {
			logger.error("File found, but error reading. Could not load azkaban config file", e);
		}
		
		return props;
	}
	
	/**
	 * Loads the Azkaban property file from the AZKABAN_HOME conf directory
	 * 
	 * @return
	 */
	private static Props loadConfigurationFromAzkabanHome() {
		String azkabanHome = System.getenv("AZKABAN_HOME");

		if (azkabanHome == null) {
			logger.error("AZKABAN_HOME not set. Will try default.");
			return null;
		}

		if (!new File(azkabanHome).isDirectory() || !new File(azkabanHome).canRead()) {
			logger.error(azkabanHome + " is not a readable directory.");
			return null;
		}

		File confPath = new File(azkabanHome, DEFAULT_CONF_PATH);
		if (!confPath.exists() || !confPath.isDirectory()
				|| !confPath.canRead()) {
			logger.error(azkabanHome + " does not contain a readable conf directory.");
			return null;
		}

		return loadAzkabanConfigurationFromDirectory(confPath);
	}
	
	public abstract Props getServerProps();
	
	public abstract SessionCache getSessionCache();
	
	public abstract VelocityEngine getVelocityEngine();
	
	public abstract UserManager getUserManager();
	
}