Java application can't read file from Resources

[BTony95]

My actions before raising this issue

• Followed the troubleshooting guide
• Read/searched the docs
• Searched past issues

Expected Behaviour

I am currently experimenting with Openfaas and Java. I made a simple function to check the body of an HTTP call against a JSON schema.This JSON schema is read from the resources folder.

Current Behaviour

Once deployed on the openfaas environment in my kubernetes cluster it fails to read the file
I get an error of the following type:

2019/07/05 12:40:13 stdout: 2019-07-05 12:40:13 ERROR Utils - Exception:                                                    
webhook-xxxxxxxxx-xxxxx:webhook java.io.FileNotFoundException: file:/home/app/entrypoint-1.0/lib/function-1.0.jar!/InputSchema.json (No such file or directory)                                                                                

Context

The flow of my program:

1. Openfaas receives an HTTP call with JSON body
2. Load Input schema from Resources
3. Check the body against the schema
4. Returns status code 200 if correct or 400 if wrong

Your Environment

• FaaS-CLI version: 0.8.19

• Docker version: 18.09.6

• Are you using Docker Swarm or Kubernetes (FaaS-netes)? Kubernetes

• Operating System and version (e.g. Linux, Windows, MacOS): Linux

• Code example or link to GitHub repo or gist to reproduce problem:

public static String readResource(String fileName) {

        StringBuilder result = new StringBuilder();

        //Get file from resources folder
        ClassLoader classLoader = Utils.class.getClassLoader();
        File file = new File(classLoader.getResource(fileName).getFile());

        try (Scanner scanner = new Scanner(file)) {

            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                result.append(line).append("\n");
            }
            System.out.println(result);
            scanner.close();

        } catch (IOException ex) {
            log.error("Exception: ", ex);
        }
        return result.toString();

    }

[alexellis]

I'm moving this issue to the templates repo where the Java code exists.

[alexellis]

See also: #86 by @ivanayov

[ieugen]

@BTony95 : can you check if the resource is in the jar file ?
kubectl exec into the container, unzip and check the file.

Also this might help: https://www.baeldung.com/java-classpath-resource-cannot-be-opened .

try (InputStream inputStream = getClass().getResourceAsStream("/input.txt");
	    BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream))) {
	    String contents = reader.lines()
	      .collect(Collectors.joining(System.lineSeparator()));
}

[ybasapur]

@BTony95 : can you check if the resource is in the jar file ?
kubectl exec into the container, unzip and check the file.

Also this might help: https://www.baeldung.com/java-classpath-resource-cannot-be-opened .

try (InputStream inputStream = getClass().getResourceAsStream("/input.txt");
	    BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream))) {
	    String contents = reader.lines()
	      .collect(Collectors.joining(System.lineSeparator()));
}

best solution I come across, after struggling for many hours to make it work.