Lambda calling a external HTTP endpoint

[RajasGujarathi]

I am running a Moto Server

@pytest.fixture(scope="module")
def moto_server():
    """Fixture to run a mocked AWS server for testing."""
    # Note: pass `port=0` to get a random free port.
    server = ThreadedMotoServer(port=0)
    server.start()
    host, port = server.get_host_and_port()
    yield f"http://{host}:{port}"
    server.stop()

and invoking a Lambda function,

lambdafn.invoke(
            FunctionName=<...>,
            InvocationType='RequestResponse',
            Payload=json.dumps(records,indent=4)
        )

The invoked Lambda tries to make a call to an external HTTP endpoint, whose response in this case is mocked. However, Lambda is not getting the correct mocked response. I suspect something to do with the hostname in the mocked response 🤔

I am using the @responses.activate to mock the response.

The mocked response

responses.add(
        responses.GET,
        f'http://127.0.0.1:80/api/v1/health',
        json={
                "meta": {
                    "status": "healthy"
                }
            },
        status=200
    )

However, I get 👇

HTTPConnectionPool(host='127.0.0.1', port=80): Max retries exceeded with url: /api/v1/health (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0xf06f06e85010>: Failed to establish a new connection: [Errno 111] Connection refused'))

Any suggestions?

[RajasGujarathi]

@bblommers tagging with a hope that something similar is known to you

[felixscherz]

Hi, I think this happens because moto runs your lambda function inside a docker container which means the responses.activate is not applied because your lambda code runs in a different environment. You could try to provide a separate http server for the lambda to call and mock responses that way.

moto/moto/awslambda/models.py

Lines 1048 to 1058 in 8007aef

	container = self.docker_client.containers.run(
	image_ref,
	[self.handler, json.dumps(event)],
	remove=False,
	mem_limit=f"{self.memory_size}m",
	volumes=volumes,
	environment=env_vars,
	detach=True,
	log_config=log_config,
	**run_kwargs,
	)

Let me know if that helped or not:)

[RajasGujarathi]

Thanks, will try with a HTTP server