Can't poll from S3 with a custom endpoint configuration

Xavier FRANCOIS :

I try to use spring-integration-aws to poll from a S3 bucket to trigger a spring-batch job. My S3 bucket is not hosted on Amazon, it's on a local minio server, so I got a custom configuration :

    @Bean
    public AmazonS3 amazonS3(ConfigProperties configProperties) {

        return AmazonS3ClientBuilder.standard()
                .withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration("http://localhost:9001","eu-west-0")) // Region matches with minio region
                .withPathStyleAccessEnabled(configProperties.getS3().isPathStyle())
                .withCredentials(new AWSStaticCredentialsProvider(new BasicAWSCredentials(
                        configProperties.getS3().getAccessKey(), configProperties.getS3().getSecretKey()
                ))).build();
    }

I defined my IntegrationFlow this way :

  @Bean
    public IntegrationFlow s3InboundFlow() {

        S3RemoteFileTemplate template = new S3RemoteFileTemplate(new S3SessionFactory(amazonS3));
        S3StreamingMessageSource s3StreamingMessageSource = new S3StreamingMessageSource(template);
        s3StreamingMessageSource.setRemoteDirectory(String.format("%s/OUT/", configProperties.getS3().getBucketDataPath()));

        return IntegrationFlows.from(s3StreamingMessageSource, configurer -> configurer
                .id("s3InboundAdapter")
                .autoStartup(true)
                .poller(Pollers.fixedDelay(POLL, TimeUnit.SECONDS)))
                .handle(jobLaunchingGateway(jobRepository)) // Launch a spring-batch job
                .get();
    }

The problem is, when the polling occured, I got the following error :

Caused by: java.lang.IllegalStateException: S3 client with invalid S3 endpoint configured: localhost:9001
    at com.amazonaws.services.s3.AmazonS3Client.getRegion(AmazonS3Client.java:4270)

It happens because when the file is received, some headers are set in spring-integration-aws :

AbstractRemoteFileStreamingMessageSource.java

return getMessageBuilderFactory()
            .withPayload(session.readRaw(remotePath))
            .setHeader(IntegrationMessageHeaderAccessor.CLOSEABLE_RESOURCE, session)
            .setHeader(FileHeaders.REMOTE_DIRECTORY, file.getRemoteDirectory())
            .setHeader(FileHeaders.REMOTE_FILE, file.getFilename())
            .setHeader(FileHeaders.REMOTE_HOST_PORT, session.getHostPort())
            .setHeader(FileHeaders.REMOTE_FILE_INFO,
                                    this.fileInfoJson ? file.toJson() : file);

The REMOTE_HOST_PORT header is set thanks to getHostPort() method. The getHostPort() in S3Session.java then calls the getRegion() method.

The getRegion() method in AmazonS3Client is not checking if a value is set by the user in signerRegionOverride field. It only checks if the host is matching the "amazonaws.com" pattern.

@Override
    public String getHostPort() {
        Region region = this.amazonS3.getRegion().toAWSRegion();
        return String.format("%s.%s.%s:%d", AmazonS3.ENDPOINT_PREFIX, region.getName(), region.getDomain(), 443);
    }

   @Override
    public synchronized Region getRegion() {
        String authority = super.endpoint.getAuthority();
        if (Constants.S3_HOSTNAME.equals(authority)) {
            return Region.US_Standard;
        } else {
            Matcher m = Region.S3_REGIONAL_ENDPOINT_PATTERN.matcher(authority);
            if (m.matches()) {
                return Region.fromValue(m.group(1));
            } else {
                throw new IllegalStateException(
                    "S3 client with invalid S3 endpoint configured: " + authority);
            }
        }
    }

How is it possible to poll from S3 with a custom endpoint configuration ? Why is the getHostPort() method not checking the signing region value ? Is it possible to workaround this ?

Artem Bilan :

Yes, it is possible to workaround. You just extend an S3SessionFactory to return an extension of S3Session with overridden getHostPort() method for your custom endpoint.

public class MyS3SessionFactory extends S3SessionFactory {

    private MyS3Session s3Session;

    @Override
    public S3Session getSession() {
        return s3Session;
    }

    public MyS3SessionFactory(AmazonS3 amazonS3) {
        super(amazonS3);
        Assert.notNull(amazonS3, "'amazonS3' must not be null.");
        this.s3Session = new MyS3Session(amazonS3);
    }
}

public class MyS3Session extends S3Session {

    public MyS3Session(AmazonS3 amazonS3) {
        super(amazonS3);
    }

    @Override
    public String getHostPort() {
        return "";
    }
}

Let's discuss a possible fix in the issue you have raised: https://github.com/spring-projects/spring-integration-aws/issues/160 !