aws-events: Rule schedule property type checking failing Python

[danielwilton-metoffice]

Describe the bug

Specifying aws_events.Schedule.rate(core.Duration.minutes(30)) for the schedule property on aws_events.Rule class, fails on aws-cdk-lib==2.97.0 at synth time.

This is also the same for the cron and expression properties.

type of argument schedule must be one of (aws_cdk.aws_events.Schedule, NoneType); got aws_cdk._ScheduleProxy instead

Expected Behavior

This was previously working to create an Event Rule:

lambda_event = aws_events.Rule(
    self,
    "LambdaEventName",
    description="Trigger x lambda",
    enabled=True,
    schedule=aws_events.Schedule.rate(core.Duration.minutes(30)),
    targets=[lambda_target],
)

Current Behavior

Error at synth time:

TypeError: type of argument schedule must be one of (aws_cdk.aws_events.Schedule, NoneType); got aws_cdk._ScheduleProxy instead.

Reproduction Steps

Install latest aws-cdk-lib in Python and create an aws_event.Rule object with the schedule property set to aws_events.Schedule.rate(core.Duration.minutes(30)), and run cdk synth.

Possible Solution

Workaround:

aws-cdk-lib==2.96.0

Additional Information/Context

No response

CDK CLI Version

2.96.2 (build 3edd240) and 2.97.0 (build d7cf3be)

Framework Version

2.97.0

Node.js Version

20.7.0

OS

Windows

Language

Python

Language Version

Python 3.9.17

Other information

With the Schedule functionality getting moved to core and the aws_events.Schedule now inheriting this version, I'm guessing there are some proxying issues with jsii?

[danielwilton-metoffice]

Linked issue: #27259

I believe this is because the new core.Schedule functionality is actually returning a core.LiteralSchedule that extends the core.Schedule class, which has protected members and isn't the matching consumer aws_events.Schedule with public members, causing issues when compiled with JSII.

[danielwilton-metoffice]

Created a fork, and reverted rate to use a LiteralSchedule that inherits from the consumer Schedule abstract class and that does fix the issue:
9795d1b

However, this does mean that there will be more repeated code, that I understand the refactor was aiming to avoid. Struggling to think of a way around this otherwise currently as Parameterised Types can't be used with jsii.

[peterwoodworth]

Thanks for the report @danielwilton-metoffice, I'm going to close this in favor of #27259 🙂

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