org.apache.druid.common.aws.LazyFileSessionCredentialsProvider Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.druid.common.aws;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSCredentialsProvider;
import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
public class LazyFileSessionCredentialsProvider implements AWSCredentialsProvider
{
private final AWSCredentialsConfig config;
/**
* The field is declared volatile in order to ensure safe publication of the object
* in {@link #getUnderlyingProvider()} without worrying about final modifiers
* on the fields of the created object
*
* @see
* https://github.com/apache/druid/pull/6662#discussion_r237013157
*/
@MonotonicNonNull
private volatile FileSessionCredentialsProvider provider;
public LazyFileSessionCredentialsProvider(AWSCredentialsConfig config)
{
this.config = config;
}
@EnsuresNonNull("provider")
private FileSessionCredentialsProvider getUnderlyingProvider()
{
FileSessionCredentialsProvider syncedProvider = provider;
if (syncedProvider == null) {
synchronized (config) {
syncedProvider = provider;
if (syncedProvider == null) {
syncedProvider = new FileSessionCredentialsProvider(config.getFileSessionCredentials());
provider = syncedProvider;
}
}
}
return syncedProvider;
}
@Override
public AWSCredentials getCredentials()
{
return getUnderlyingProvider().getCredentials();
}
@Override
public void refresh()
{
getUnderlyingProvider().refresh();
}
}