/*
* Copyright 2013-2014 Erudika. http://erudika.com
*
* 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.
*
* For issues and patches go to: https://github.com/erudika
*/
package com.erudika.para.persistence;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodbv2.model.AttributeDefinition;
import com.amazonaws.services.dynamodbv2.model.CreateTableRequest;
import com.amazonaws.services.dynamodbv2.model.DeleteTableRequest;
import com.amazonaws.services.dynamodbv2.model.KeySchemaElement;
import com.amazonaws.services.dynamodbv2.model.KeyType;
import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput;
import com.amazonaws.services.dynamodbv2.model.ScalarAttributeType;
import com.erudika.para.Para;
import com.erudika.para.utils.Config;
import java.util.List;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Helper utilities for connecting to AWS DynamoDB.
* @author Alex Bogdanovski [alex@erudika.com]
*/
public final class AWSDynamoUtils {
private static AmazonDynamoDBClient ddbClient;
private static final String LOCAL_ENDPOINT = "http://localhost:8000";
private static final String ENDPOINT = "dynamodb.".concat(Config.AWS_REGION).concat(".amazonaws.com");
private static final Logger logger = LoggerFactory.getLogger(AWSDynamoUtils.class);
private AWSDynamoUtils() { }
/**
* Returns a client instance for AWS DynamoDB
* @return a client that talks to DynamoDB
*/
public static AmazonDynamoDBClient getClient() {
if (ddbClient != null) {
return ddbClient;
}
if (Config.IN_PRODUCTION) {
ddbClient = new AmazonDynamoDBClient();
ddbClient.setEndpoint(ENDPOINT);
} else {
ddbClient = new AmazonDynamoDBClient(new BasicAWSCredentials("local", "null"));
ddbClient.setEndpoint(LOCAL_ENDPOINT);
}
Para.addDestroyListener(new Para.DestroyListener() {
public void onDestroy() {
shutdownClient();
}
});
return ddbClient;
}
/**
* Stops the client and releases resources.
* <b>There's no need to call this explicitly!</b>
*/
public static void shutdownClient() {
if (ddbClient != null) {
ddbClient.shutdown();
ddbClient = null;
}
}
/**
* Checks if the main table exists in the database.
* @param appid name of the {@link com.erudika.para.core.App}
* @return true if the table exists
*/
public static boolean existsTable(String appid) {
if (StringUtils.isBlank(appid)) {
return false;
}
try {
List<String> tables = getClient().listTables().getTableNames();
return tables != null && tables.contains(appid);
} catch (Exception e) {
return false;
}
}
/**
* Creates the main table.
* @param appid name of the {@link com.erudika.para.core.App}
* @return true if created
*/
public static boolean createTable(String appid) {
return createTable(appid, 2L, 1L);
}
/**
* Creates a table in AWS DynamoDB.
* @param appid name of the {@link com.erudika.para.core.App}
* @param readCapacity read capacity
* @param writeCapacity write capacity
* @return true if created
*/
public static boolean createTable(String appid, Long readCapacity, Long writeCapacity) {
if (StringUtils.isBlank(appid) || StringUtils.containsWhitespace(appid) || existsTable(appid)) {
return false;
}
try {
getClient().createTable(new CreateTableRequest().withTableName(appid).
withKeySchema(new KeySchemaElement(Config._KEY, KeyType.HASH)).
withAttributeDefinitions(new AttributeDefinition().withAttributeName(Config._KEY).
withAttributeType(ScalarAttributeType.S)).
withProvisionedThroughput(new ProvisionedThroughput(readCapacity, writeCapacity)));
} catch (Exception e) {
logger.error(null, e);
return false;
}
return true;
}
/**
* Deletes the main table from AWS DynamoDB.
* @param appid name of the {@link com.erudika.para.core.App}
* @return true if deleted
*/
public static boolean deleteTable(String appid) {
if (StringUtils.isBlank(appid) || !existsTable(appid)) {
return false;
}
try {
getClient().deleteTable(new DeleteTableRequest().withTableName(appid));
} catch (Exception e) {
logger.error(null, e);
return false;
}
return true;
}
}