software.amazon.awssdk.regions.providers.InstanceProfileRegionProvider Maven / Gradle / Ivy
/*
* Copyright 2010-2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. 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 software.amazon.awssdk.regions.providers;
import software.amazon.awssdk.annotations.SdkProtectedApi;
import software.amazon.awssdk.core.SdkSystemSetting;
import software.amazon.awssdk.core.exception.SdkClientException;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.regions.internal.util.EC2MetadataUtils;
/**
* Attempts to load region information from the EC2 Metadata service. If the application is not
* running on EC2 this provider will thrown an exception.
*
*
* If {@link SdkSystemSetting#AWS_EC2_METADATA_DISABLED} is set to true, it will not try to load
* region from EC2 metadata service and will return null.
*/
@SdkProtectedApi
public final class InstanceProfileRegionProvider implements AwsRegionProvider {
/**
* Cache region as it will not change during the lifetime of the JVM.
*/
private volatile String region;
@Override
public Region getRegion() throws SdkClientException {
if (SdkSystemSetting.AWS_EC2_METADATA_DISABLED.getBooleanValueOrThrow()) {
throw SdkClientException.builder()
.message("EC2 Metadata is disabled. Unable to retrieve region information from " +
"EC2 Metadata service.")
.build();
}
if (region == null) {
synchronized (this) {
if (region == null) {
this.region = tryDetectRegion();
}
}
}
if (region == null) {
throw SdkClientException.builder()
.message("Unable to retrieve region information from EC2 Metadata service. "
+ "Please make sure the application is running on EC2.")
.build();
}
return Region.of(region);
}
private String tryDetectRegion() {
return EC2MetadataUtils.getEC2InstanceRegion();
}
}