ConfigurationSettings.java

/*
 * Copyright 2014 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.amediamanager.config;

import java.io.IOException;
import java.util.Enumeration;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.context.annotation.Scope;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import com.amazonaws.auth.AWSCredentialsProvider;

/**
 * The ConfigurationSettings class is a singleton class that retrieves the
 * settings from the aMediaManager.properties file or from the EC2 Metadata URL
 * or Elastic Beanstalk Environment Metadata.
 */
@Component
@Scope(ConfigurableBeanFactory.SCOPE_SINGLETON)
public class ConfigurationSettings {

	private static final Logger LOG = LoggerFactory
			.getLogger(ConfigurationSettings.class);

	/** Available config properties **/
	public static enum ConfigProps {
		S3_UPLOAD_BUCKET,
		S3_UPLOAD_PREFIX,
		S3_PROFILE_PIC_PREFIX,
		DEFAULT_PROFILE_PIC_KEY,
		DEFAULT_VIDEO_POSTER_KEY,
		CACHE_ENDPOINT,
		CACHE_PORT,
		CACHE_ENABLED,
		RDS_DATABASE,
		RDS_USERNAME,
		RDS_PASSWORD,
		RDS_INSTANCEID,
		DDB_USERS_TABLE,
		AWS_REGION,
		TRANSCODE_TOPIC,
		TRANSCODE_QUEUE,
		TRANSCODE_ROLE,
		TRANSCODE_PIPELINE,
		TRANSCODE_PRESET
	}

	@Autowired
	private AWSCredentialsProvider credsProvider;
	private ConfigurationProviderChain configProviderChain;

	public ConfigurationSettings() throws IOException {
		try {
			LOG.debug("Initializing ConfigurationProviderChain");
			this.configProviderChain = new ConfigurationProviderChain(
					new S3EnvConfigurationProvider(),
					new S3FileConfigurationProvider(),
					new ClassResourceConfigurationProvider("/app.properties"));
			LOG.debug("ConfigurationProviderChain initialized");
			LOG.info("Config provider: "
					+ this.configProviderChain.getTheProvider().getClass()
							.getSimpleName());
			LOG.info("---------------------");
			LOG.info("Effective config:");
			this.configProviderChain.getProperties().list(System.out);
		} catch (Exception ex) {
			LOG.error("An exception was thrown while creating the ConfigurationSettings object. Application will not run.", ex);
		}

	}

	/**
	 * This method returns the AWS credentials object.
	 * 
	 * @return AWS credentials taken from the properties and user-data.
	 */
	public AWSCredentialsProvider getAWSCredentialsProvider() {
		return credsProvider;
	}

	/**
	 * Thsi method returns the ConfigurationProvider
	 * 
	 * @return
	 */
	public ConfigurationProvider getConfigurationProvider() {
		return configProviderChain.getTheProvider();
	}

	@Scheduled(fixedDelay = 60000)
	public void refreshConfigurationProvider() {
		this.configProviderChain.loadProperties();
		LOG.debug("Refreshed properties:");
		LOG.debug(toString());
	}

	/**
	 * Accessor for the various properties in the configuration.
	 * 
	 * @param propertyName
	 *            the name of the property key. The static strings on this class
	 *            can also be used.
	 * @return the value of the property.
	 */
	public String getProperty(ConfigurationSettings.ConfigProps property_name) {
		return configProviderChain.getProperties().getProperty(
				property_name.name());
	}

	/**
	 * This method returns aMediaManager configuration settings as a string of
	 * key-value pairs.
	 * 
	 * @return aMediaManager configuration parameters from running environment.
	 */
	@Override
	public String toString() {
		StringBuilder sb = new StringBuilder();
		Enumeration<?> e = this.configProviderChain.getProperties()
				.propertyNames();
		while (e.hasMoreElements()) {
			String key = (String) e.nextElement();
			sb.append(key);
			sb.append("=");
			sb.append(configProviderChain.getProperties().getProperty(key));
			sb.append("\n");
		}

		return sb.toString();
	}
}