JWT Token Google Cloud Run - google-cloud-platform

Question

I am developing an application with JWT authentication on the google cloud platform. Server side I added authentication via Cloud API Gateway to a cloud run backend. Now I am making a client to generate the JWT token and pass it in the call. To do this I am creating an application that must be deployed on CloudRun and I am following this documentation: https://cloud.google.com/api-gateway/docs/authenticate-service-account#making_an_authenticated_request. My problem is that I don't know how to indicate what it requires as saKeyfile. I tried to put only the name of the file that under src / main / resources / filetest.json but once I try to call the method it tells me file not found. I tried to indicate also the full path. Can anyone help me?
PS I'm using Java
EDIT:
here is my code which is the same of documentation
public void makeCall() {
String fullPath="src/main/resources/TEST1-id.json";
String saEmail="testsa#projectID.iam.gserviceaccount.com";
String audience="auth";
int expiryLenght=600;
String token;
try {
token=generateJwt(fullPath,saEmail,audience,expiryLenght);
System.out.println("Token generated: "+token);
URL url = new URL("apigatewayurl");
makeJwtRequest(token, url);
System.out.println("Call performed");
} catch (IOException e) {
e.printStackTrace();
}
}
private static String generateJwt(final String saKeyfile, final String saEmail,
final String audience, final int expiryLength)
throws FileNotFoundException, IOException {
Date now = new Date();
Date expTime = new Date(System.currentTimeMillis() + TimeUnit.SECONDS.toMillis(expiryLength));
// Build the JWT payload
JWTCreator.Builder token = JWT.create()
.withIssuedAt(now)
// Expires after 'expiraryLength' seconds
.withExpiresAt(expTime)
// Must match 'issuer' in the security configuration in your
// swagger spec (e.g. service account email)
.withIssuer(saEmail)
// Must be either your Endpoints service name, or match the value
// specified as the 'x-google-audience' in the OpenAPI document
.withAudience(audience)
// Subject and email should match the service account's email
.withSubject(saEmail)
.withClaim("email", saEmail);
// Sign the JWT with a service account
FileInputStream stream = new FileInputStream(saKeyfile);
ServiceAccountCredentials cred = ServiceAccountCredentials.fromStream(stream);
RSAPrivateKey key = (RSAPrivateKey) cred.getPrivateKey();
Algorithm algorithm = Algorithm.RSA256(null, key);
return token.sign(algorithm);
}
i've tried to use full path like in example and using only /TEST1-id.json
and here there is project structure. Is a springboot application which i will deploy in cloud run

Answer 1

The OP fixed the issue on this way
In the end I put the file in the root and copied it in the docker image and recover it as an environment variable in cloud run