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Localstack Module

Testcontainers module for the Atlassian's LocalStack, 'a fully functional local AWS cloud stack'.

Usage example

Running LocalStack as a stand-in for AWS S3 during a test:

@Rule
public LocalStackContainer localstack = new LocalStackContainer()
        .withServices(S3);

@Test
public void someTestMethod() {
    // AWS SDK v1
    AmazonS3 s3 = AmazonS3ClientBuilder
                    .standard()
                    .withEndpointConfiguration(localstack.getEndpointConfiguration(S3))
                    .withCredentials(localstack.getDefaultCredentialsProvider())
                    .build();
    
            s3.createBucket("foo");
            s3.putObject("foo", "bar", "baz");

    // AWS SDK v2
    S3Client s3 = S3Client
                .builder()
                .endpointOverride(localstack.getEndpointOverride(LocalStackContainer.Service.S3))
                .credentialsProvider(StaticCredentialsProvider.create(AwsBasicCredentials.create(
                    localstack.getAccessKey(), localstack.getSecretKey()
                )))
                .region(Region.of(localstack.getRegion()))
                .build();

            s3.createBucket(b -> b.bucket("foo"));
            s3.putObject(b -> b.bucket("foo").key("bar"), RequestBody.fromBytes("baz".getBytes()));

Environment variables listed in Localstack's README may be used to customize Localstack's configuration. Use the .withEnv(key, value) method on LocalStackContainer to apply configuration settings.

HOSTNAME_EXTERNAL and hostname-sensitive services

Some Localstack APIs, such as SQS, require the container to be aware of the hostname that it is accessible on - for example, for construction of queue URLs in responses.

Testcontainers will inform Localstack of the best hostname automatically, using the HOSTNAME_EXTERNAL environment variable:

  • when running the Localstack container directly without a custom network defined, it is expected that all calls to the container will be from the test host. As such, the container address will be used (typically localhost or the address where the Docker daemon is running).

    Localstack container running without a custom network inside_block:without_network

  • when running the Localstack container with a custom network defined, it is expected that all calls to the container will be from other containers on that network. HOSTNAME_EXTERNAL will be set to the last network alias that has been configured for the Localstack container.

    Localstack container running without a custom network inside_block:with_network

  • Other usage scenarios, such as where the Localstack container is used from both the test host and containers on a custom network are not automatically supported. If you have this use case, you should set HOSTNAME_EXTERNAL manually.

Adding this module to your project dependencies

Add the following dependency to your pom.xml/build.gradle file:

testCompile "org.testcontainers:localstack:{{latest_version}}"
<dependency>
    <groupId>org.testcontainers</groupId>
    <artifactId>localstack</artifactId>
    <version>{{latest_version}}</version>
    <scope>test</scope>
</dependency>