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1/*
2 * Copyright 2012-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License").
5 * You may not use this file except in compliance with the License.
6 * A copy of the License is located at
7 *
8 *  http://aws.amazon.com/apache2.0
9 *
10 * or in the "license" file accompanying this file. This file is distributed
11 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
12 * express or implied. See the License for the specific language governing
13 * permissions and limitations under the License.
14 */
15package com.amazonaws.auth;
16
17import static com.amazonaws.SDKGlobalConfiguration.ACCESS_KEY_ENV_VAR;
18import static com.amazonaws.SDKGlobalConfiguration.ALTERNATE_ACCESS_KEY_ENV_VAR;
19import static com.amazonaws.SDKGlobalConfiguration.ALTERNATE_SECRET_KEY_ENV_VAR;
20import static com.amazonaws.SDKGlobalConfiguration.SECRET_KEY_ENV_VAR;
21import static com.amazonaws.SDKGlobalConfiguration.AWS_SESSION_TOKEN_ENV_VAR;
22
23import com.amazonaws.AmazonClientException;
24import com.amazonaws.util.StringUtils;
25
26/**
27 * {@link AWSCredentialsProvider} implementation that provides credentials
28 * by looking at the: <code>AWS_ACCESS_KEY_ID</code> (or <code>AWS_ACCESS_KEY</code>) and
29 * <code>AWS_SECRET_KEY</code> (or <code>AWS_SECRET_ACCESS_KEY</code>) environment variables.
30 */
31public class EnvironmentVariableCredentialsProvider implements AWSCredentialsProvider {
32    @Override
33    public AWSCredentials getCredentials() {
34        String accessKey = System.getenv(ACCESS_KEY_ENV_VAR);
35        if (accessKey == null) {
36            accessKey = System.getenv(ALTERNATE_ACCESS_KEY_ENV_VAR);
37        }
38
39        String secretKey = System.getenv(SECRET_KEY_ENV_VAR);
40        if (secretKey == null) {
41            secretKey = System.getenv(ALTERNATE_SECRET_KEY_ENV_VAR);
42        }
43
44        accessKey = StringUtils.trim(accessKey);
45        secretKey = StringUtils.trim(secretKey);
46        String sessionToken =
47            StringUtils.trim(System.getenv(AWS_SESSION_TOKEN_ENV_VAR));
48
49        if (StringUtils.isNullOrEmpty(accessKey)
50                || StringUtils.isNullOrEmpty(secretKey)) {
51
52            throw new AmazonClientException(
53                    "Unable to load AWS credentials from environment variables " +
54                    "(" + ACCESS_KEY_ENV_VAR + " (or " + ALTERNATE_ACCESS_KEY_ENV_VAR + ") and " +
55                    SECRET_KEY_ENV_VAR + " (or " + ALTERNATE_SECRET_KEY_ENV_VAR + "))");
56        }
57
58        return sessionToken == null ?
59                new BasicAWSCredentials(accessKey, secretKey)
60                :
61                new BasicSessionCredentials(accessKey, secretKey, sessionToken);
62    }
63
64    @Override
65    public void refresh() {}
66
67    @Override
68    public String toString() {
69        return getClass().getSimpleName();
70    }
71}