weberc2 / nimbus Goto Github PK

Intro

Ideally attributes are accessed as properties (e.g., Bucket.Arn). Today they are accessed via accessor methods (e.g., Bucket.GetArn()). The Get prefix is necessary because frequently a Resource will have properties and attributes with the same name, and the Get allows us to disambiguate. In cases where there is an attribute and a property with the same name, it would be easy to accidentally access the property when you were intending to access the attribute (the static type checker will save those who use it, but even they might have a bit of confusion trying to debug the type checker error message).

Proposal

To address this, I propose making resources with this template:

class MyResource:
    def __init__(self, {prop_0}, {prop_1}, ... {prop_n}) -> None:
        self._{prop_0} = {prop_0}
        self._{prop_1} = {prop_1}
        ...
        self._{prop_n} = {prop_n}

    @property
    def {Attr0}(self) -> {attribute_python_type(Attr0)}:
        return {attribute_python_type(Attr0)}(self, {Attr0})

Scenario: Mutating properties

Since mutating properties isn't supported today, this is no worse in that regard. Further, if we wanted to support mutating properties, we could still provide SetProperty() methods (this is less natural in Python, but it feels more natural for this application to leave the getattr syntax for attributes.

Scenario: Accessing properties

Similarly, accessing properties via the __getattr__ syntax doesn't feel like a very natural use pattern; if someone needs a handle for a property, they can use whatever was passed into the constructor--if that thing was a literal of some sort, they can put the literal in a variable before passing it into the constructor. If we really want to support this case, we could support it with a GetProperty() method.

Alternative proposals

• Namespacing attributes and properties to be explicit / disambiguate?
  • e.g., properties are PropBucketName instead of BucketName and attributes are AttrArn instead of Arn (possibly even .AttrArn() # method instead of `.AttrArn # @Property)?

For now, set up CI to run mypy for non-generated code only

Currently only string attributes are generated.

Currently the reference() method for property types raises NotImplementedError. This is preventing me from using the BucketEncryption property type in an S3 bucket example.

i don't see a license file in the repo, in the setup, or a header in the files, please provide one else now can really look at or contribute.

on a separate note, also out of curiosity, why bazel?