Use case
I'd like to decorate class methods with APIGatewayRestResolver's router.
Particularly, I want to use constructor injection in my app. Support dependency injection in lambda parameters is good prerequisite reading.
Here is illustrative code. We have a GET that queries Dynamo with animal_id and returns a JSON response:
class App:
resolver = APIGatewayRestResolver()
def __init__(
self,
dynamo_client: DynamoClient = DynamoClient(ANIMAL_TABLE)
):
self.dynamo_client = dynamo_client
@resolver.get("/animal/<animal_id>")
def get_animal(self, animal_id):
result = self.dynamo_client.get_item_by_key("animal_id", animal_id)
payload = json.dumps(result.get("data", []))
return Response(
status_code=HTTPStatus.OK,
content_type=content_types.APPLICATION_JSON,
body=payload,
)
def lambda_handler(event, context):
return App().resolver.resolve(event, context)
Currently I get the following error:
missing 1 required positional argument: 'self'
which indicates self argument isn't being passed. So I believe APIGatewayRestResolver router can't decorate class methods.
Solution/User Experience
Solution is probably:
- Configure the decorator to pass
self
Alternative solutions
Another solution is to simply use method injection as described by @heitorlessa in Support dependency injection in lambda parameters. This negates the benefits of constructor injection, which is useful when multiple methods share a client, for example.
Acknowledgment
Use case
I'd like to decorate class methods with APIGatewayRestResolver's router.
Particularly, I want to use constructor injection in my app. Support dependency injection in lambda parameters is good prerequisite reading.
Here is illustrative code. We have a GET that queries Dynamo with
animal_idand returns a JSON response:Currently I get the following error:
which indicates
selfargument isn't being passed. So I believe APIGatewayRestResolver router can't decorate class methods.Solution/User Experience
Solution is probably:
selfAlternative solutions
Another solution is to simply use method injection as described by @heitorlessa in Support dependency injection in lambda parameters. This negates the benefits of constructor injection, which is useful when multiple methods share a client, for example.
Acknowledgment