The update_function_configuration currently returns an empty dict no matter what but certain lambda libraries (ie, Zappa) require a realistic return value... which is simply the current config after being updated.

https://github.com/localstack/localstack/blob/9cba1010dfcbf2b7672df4d7da46b7e8ab287f64/localstack/services/awslambda/lambda_api.py#L872

https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/lambda.html#Lambda.Client.update_function_configuration

There might also be some other magic enriching that result but my quick read-through looks like it's an empty dict.



<!-- Love localstack? Please consider supporting our collective:
👉  https://opencollective.com/localstack/donate -->
self.s3_client.create_bucket(Bucket=bucket_name)
        self.s3_client.upload_fileobj(
            BytesIO(zip_file), bucket_name, bucket_key)
        
        self.lambda_client.create_function(
            FunctionName=lambda_name, Handler='handler.handler',
            Runtime=lambda_api.LAMBDA_RUNTIME_PYTHON27, Role='r1',
            Code={
                'S3Bucket': bucket_name,
                'S3Key': bucket_key
            }
        )
        
        data_before = b'{"foo": "bar with \'quotes\\""}'
        result = self.lambda_client.invoke(
            FunctionName=lambda_name, Payload=data_before)
        data_after = json.loads(result['Payload'].read())
        self.assertEqual(json.loads(to_str(data_before)), data_after['event'])
        context = data_after['context']
        self.assertEqual('$LATEST', context['function_version'])
        self.assertEqual(lambda_name, context['function_name'])
        
        testutil.delete_lambda_function(lambda_name)
    def test_python_lambda_running_in_docker(self):
        if not use_docker():
            return
        zip_file = testutil.create_lambda_archive(
            load_file(TEST_LAMBDA_PYTHON3),
            get_content=True,
            libs=TEST_LAMBDA_LIBS,