SpringBoot : ServletContext resource cannot resolve S3 URL

Question

I'm developing a Spring Boot application in which I'm integrating Amazon S3 service.
This class is my repository to access the S3 bucket :

public class S3FileRepository implements ImageRepository {

private String bucket;
private AmazonS3 s3Client;
private ResourceLoader resourceLoader;

public S3FileRepository(ResourceLoader resourceLoader, AmazonS3 s3Client, String bucket) {
    this.resourceLoader = resourceLoader;
    this.s3Client = s3Client;
    this.bucket = bucket;
}

private static String toS3Uri(String bucket, String imageName) {
    return String.format("s3://%s/%s", bucket, imageName);
}

@Override
public Resource getImage(String name) {
    return resourceLoader.getResource(S3FileRepository.toS3Uri(this.bucket, name).concat(this.IMAGE_EXTENSION));
}

using Spring Boot Autoconfiguration as suggested.
So in my pom.xml, among other things, I've

<dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-aws-autoconfigure</artifactId>
        <version>2.1.1.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-aws-context</artifactId>
        <version>2.1.1.RELEASE</version>
    </dependency>

Moreover I've an application.properties done like this:

cloud.aws.credentials.accessKey= (mykey)
cloud.aws.credentials.secretKey= (mysecret)
cloud.aws.credentials.instanceProfile=true
cloud.aws.region.static=eu-west-2
cloud.aws.stack.auto=false

The problem:

Everything works fine if i compile my project and then I simply run the JAR with java -jar target/myproject.jar, i correctly get the image that I ask for and everything is fine.

Instead if I run the project with the IDE default mvn spring-boot:run when I try to get an image (present in the bucket) an Exception occour saying following:

    ServletContext resource [/s3://mybucket/test.jpeg] cannot be resolved to URL because it does not exist
java.io.FileNotFoundException: ServletContext resource [/s3://mybucket/test.jpeg] cannot be resolved to URL because it does not exist

So what I think is that it throws an Exception because it's like it goes inside the jar to look for something that match s3://mybucket/test.jpeg but I can't get why, and why it happens only running the project with mvn spring-boot:run and not running the jar.

You'll need to specify both which IDE and the full stack trace of the error. (Note that unless you're needing to process the image locally it's a lot easier on everyone for you to just return an HTTP S3 URI to the client; jets3t makes generating signed URIs simpler.) — chrylis -cautiouslyoptimistic-, Mar 20 '19 at 02:05

score 3 · Accepted Answer · answered Mar 26 '19 at 16:34

You're likely hitting the spring-cloud-aws issue #384 whereupon the spring-boot-devtools dependency, which is activated when you start the application from the IDE, activates a different code path in resource loading.

You can test whether you're hitting this issue by removing the spring-boot-devtools dependency from your pom.xml file, reloading the project in your IDE, and running the same test.

score 0 · Answer 2 · answered Mar 22 '19 at 14:43

There is a difference between app's launching with "java -jar" and "mvn spring-boot:run". From Spring Boot docs: "The Spring Boot Maven plugin includes a run goal that can be used to quickly compile and run your application. Applications run in an exploded form, as they do in your IDE". It can be a reason of problem.

SpringBoot : ServletContext resource cannot resolve S3 URL

The problem:

2 Answers2