Invoking AWS Lambda endpoint

Question

I implemented AWS lambda method to learn what I can do with it. What I have now:

AWS lambda itself
API Gateway
Amazon CloudWatch Logs

In API Gateway configs I see next options:

Endpoint: https://xyz.execute-api.us-east-2.amazonaws.com/dummy/test-store
API key: QW123E45RTY6
Authorization: NONE

Behind this lambda I have Java code, implementing com.amazonaws.services.lambda.runtime.RequestStreamHandler and a REST controller behind it, something like that:

@Path("/tester")
public class TestResource {

    private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

    private TestRepository testRepository;

    public void setTestRepository(TestRepository testRepository) {
        this.testRepository = testRepository;
    }

    @POST
    @Path("/{identifier}")
    @Produces(MediaType.TEXT_PLAIN)
    @Consumes(MediaType.WILDCARD)
    public Response store(@PathParam("identifier") String identifier, @QueryParam("hashcode") String hashcode) {
        try {
            this.testRepository.store(identifier, hashcode);
        } catch (RuntimeException ex) {
            LOG.error("Failed to store pair {}, {}", identifier, hashcode, ex);
            throw new InternalServerErrorException(ex);
        }
        return Response.noContent().build();
    }
}

Now I tried invoking this service through Postman:

Option 1 - Invoke what I saw in API Gateway:

URL: https://xyz.execute-api.us-east-2.amazonaws.com/dummy/test-store
Method: POST
Headers:
- Key: x-api-key
- Value: QW123E45RTY6

Result: 404 Not Found, see the appropriate logs in AWS CloudWatch.

Option 2 - Invoke my method:

URL: https://xyz.execute-api.us-east-2.amazonaws.com/dummy/test-store/tester/qwerty123
Method: POST
Headers:
- Key: x-api-key
- Value: QW123E45RTY6

Result: 403 Forbidden, no logs in AWS CloudWatch.

{
    "message": "Missing Authentication Token"
}

I fully understand why Option 1 did not work, but what went wrong with Option 2? Could you please help me understanding what I missed?

AlexK AlexK · Accepted Answer · 2018-11-25T20:50:07

This message occurs (most of the times) when you try to call URL that doesn't exist.

Please make sure you are calling http://api-gateway-name/stage-name/resource-name

Also, make sure you have deployed your API.

Invoking AWS Lambda endpoint

2 Answers