Spring Cloud: testing S3 client with TestContainters

Question

I use Spring Cloud's ResourceLoader to access S3, e.g.:

public class S3DownUpLoader {

private final ResourceLoader resourceLoader;

@Autowired
public S3DownUpLoader(ResourceLoader resourceLoader) {
    this.resourceLoader = resourceLoader;
}
public String storeOnS3(String filename, byte[] data) throws IOException {
    String location = "s3://" + bucket + "/" + filename;
    WritableResource writeableResource = (WritableResource) this.resourceLoader.getResource(location);
    FileCopyUtils.copy( data, writeableResource.getOutputStream());
    return filename;
}

It works okey and I need help to test the code with Localstack/Testcontainers. I've tried following test, but it does not work - my production profile gets picked up(s3 client with localstack config is not injected):

@RunWith(SpringRunner.class)
@SpringBootTest
public class S3DownUpLoaderTest {

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

@Autowired
S3DownUpLoader s3DownUpLoader;

@Test
public void testA() {
     s3DownUpLoader.storeOnS3(...);
}


@TestConfiguration
@EnableContextResourceLoader
public static class S3Configuration {

    @Primary
    @Bean(destroyMethod = "shutdown")
    public AmazonS3 amazonS3() {
        return AmazonS3ClientBuilder
                .standard()
                .withEndpointConfiguration(localstack.getEndpointConfiguration(S3))
                .withCredentials(localstack.getDefaultCredentialsProvider())
                .build();
    }

}
}

Answer 1

It seems the only way to provide custom amazonS3 bean for ResourceLoader is to inject it manually. The test looks like

@RunWith(SpringRunner.class)
@SpringBootTest
@ContextConfiguration(classes = S3DownUpLoaderTest.S3Configuration.class)
public class S3DownUpLoaderTest implements ApplicationContextAware {

private static final String BUCKET_NAME = "bucket";

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

@Autowired
S3DownUpLoader s3DownUpLoader;

@Autowired
SimpleStorageProtocolResolver resourceLoader;

@Autowired
AmazonS3 amazonS3;

@Before
public void setUp(){
    amazonS3.createBucket(BUCKET_NAME);
}

@Test
public void someTestA() throws IOException {
    ....

}

@After
public void tearDown(){
    ObjectListing object_listing = amazonS3.listObjects(QLM_BUCKET_NAME);
    while (true) {
        for (S3ObjectSummary summary : object_listing.getObjectSummaries()) {
            amazonS3.deleteObject(BUCKET_NAME, summary.getKey());
        }

        // more object_listing to retrieve?
        if (object_listing.isTruncated()) {
            object_listing = amazonS3.listNextBatchOfObjects(object_listing);
        } else {
            break;
        }
    };

    amazonS3.deleteBucket(BUCKET_NAME);
}

@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    if (applicationContext instanceof ConfigurableApplicationContext) {
        ConfigurableApplicationContext configurableApplicationContext = (ConfigurableApplicationContext) applicationContext;
        configurableApplicationContext.addProtocolResolver(this.resourceLoader);
    }

}

public static class S3Configuration {

    @Bean
    public S3DownUpLoader s3DownUpLoader(ResourceLoader resourceLoader){
        return new S3DownUpLoader(resourceLoader);
    }

    @Bean(destroyMethod = "shutdown")
    public AmazonS3 amazonS3() {
        return AmazonS3ClientBuilder
                .standard()
                .withEndpointConfiguration(localstack.getEndpointConfiguration(S3))
                .withCredentials(localstack.getDefaultCredentialsProvider())
                .build();
    }

    @Bean
    public SimpleStorageProtocolResolver resourceLoader(){
        return new SimpleStorageProtocolResolver(amazonS3());
    }

}