/*
* Copyright 2013-2014 the original author or authors.
*
* 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 org.springframework.cloud.aws.core.region;
import com.amazonaws.AmazonClientException;
import com.amazonaws.regions.Region;
import com.amazonaws.regions.RegionUtils;
import com.amazonaws.util.EC2MetadataUtils;
import com.amazonaws.util.EC2MetadataUtils.InstanceInfo;
import org.springframework.util.Assert;
/**
* {@link org.springframework.cloud.aws.core.region.RegionProvider} implementation that dynamically retrieves the
* region with the EC2 meta-data. This implementation allows application to run against their region without any
* further configuration.
*
* @author Agim Emruli
* @author Gleb Schukin
*/
public class Ec2MetadataRegionProvider implements RegionProvider {
@Override
public Region getRegion() {
Region currentRegion = getCurrentRegion();
Assert.state(currentRegion != null, "There is not EC2 meta data available, because the application is not running " +
"in the EC2 environment. Region detection is only possible if the application is running on a EC2 instance");
return currentRegion;
}
protected Region getCurrentRegion() {
try {
InstanceInfo instanceInfo = EC2MetadataUtils.getInstanceInfo();
return instanceInfo != null && instanceInfo.getRegion() != null ? RegionUtils.getRegion(instanceInfo.getRegion()) : null;
} catch (AmazonClientException e) {
return null;
}
}
}