Include TypeDef for Cloudwatch Alarms Events from EventBridge

[xquek]

Describe your idea

Currently there are no typedef defined for cloudwatch alarms (or at least i cant seem to find it). https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch-and-eventbridge.ht

Code sample I am hoping that there will be stubs so we we know what keys to look up for during development

Additional context When cloudwatch alarms are triggered, we can create cloudwatch event rules to trigger a lambda. When working with the lambda, it will be awesome to have typedef for the event object.

[vemel]

Hello! Thank you for the feature request.

Unfortunately, botocore shapes use String type for Event shape, so event structure cannot be parsed from botocore shapes. However, event TypeDef can always be hardcoded manually. I will take a look at how to implement it properly.

[xquek]

thank @vemel, let me know if there is anything you need help with ! happy to contribute!

[vemel]

So, it is a tricky change. Events are strings, so this type will not be directly used in any cloudwatch methods. Another thing is that there is no way to track if botocore changes the output format in any way.

Thank you for your participation in the project!

If you want to prepare a pull request:

• Add new TypedDict to typed_dicts.py

CloudwatchEventTypeDef = TypeTypedDict(
    "CloudwatchEventTypeDef",
    [
        TypedDictAttribute("version", Type.str, True),
        ...
    ],
)

• add new types to service_package in parse_service_package, somewhere around result.type_defs = result.extract_type_defs(), use ServiceNameCatalog to check what service you are working with
• it makes sense to move TypeDefSorter(self._get_sortable_type_defs()).sort() to parse_service_package.

So end result in parse_service_package should be smth like

type_defs = self._get_sortable_type_defs()
if service_name == ServiceNameCatalog.cloudwatch:
   type_defs.add(CloudwatchEventTypeDef)
# probably we need eventbridge service as well

type_def_sorter = TypeDefSorter(self._get_sortable_type_defs())
result.type_defs = type_def_sorter.sort()

Generate and install package to cross-check:

• generate: ./scripts/build.sh -s cloudwatch --product boto3-services
• install: ./scripts/install.sh cloudwatch
• test on your sample, try to import it from mypy_boto3_cloudwatch.type_defs import CloudwatchEventTypeDef

Please let me know if you find this helpful or if you are stuck.

[vemel]

TypedDicts should be something like

CloudwatchEventStateTypeDef = TypeTypedDict(
    "CloudwatchEventStateTypeDef",
    [
        TypedDictAttribute("reason", Type.str, True),
        TypedDictAttribute("reasonData", Type.str, True),
        TypedDictAttribute("timestamp", Type.str, True),
        TypedDictAttribute("value", Type.str, True),
    ],
)

CloudwatchEventMetricTypeDef = TypeTypedDict(
    "CloudwatchEventMetricTypeDef",
    [
        TypedDictAttribute("id", Type.str, True),
        TypedDictAttribute(
            "metricStat", Type.DictStrAny, True
        ),  # probably we can improve typing here
        TypedDictAttribute("returnData", Type.bool, True),
    ],
)

CloudwatchEventConfigurationTypeDef = TypeTypedDict(
    "CloudwatchEventDetailConfigurationTypeDef",
    [
        TypedDictAttribute("description", Type.str, True),
        TypedDictAttribute("metrics", TypeSubscript(Type.List, [Type.str]), True),
    ],
)

CloudwatchEventDetailTypeDef = TypeTypedDict(
    "CloudwatchEventDetailTypeDef",
    [
        TypedDictAttribute("alarmName", Type.str, True),
        TypedDictAttribute("configuration", CloudwatchEventConfigurationTypeDef, True),
        TypedDictAttribute("previousState", CloudwatchEventStateTypeDef, True),
        TypedDictAttribute("state", CloudwatchEventStateTypeDef, True),
    ],
)

CloudwatchEventTypeDef = TypeTypedDict(
    "CloudwatchEventTypeDef",
    [
        TypedDictAttribute("version", Type.str, True),
        TypedDictAttribute("id", Type.str, True),
        TypedDictAttribute("detail-type", Type.str, True),
        TypedDictAttribute("source", Type.str, True),
        TypedDictAttribute("account", Type.str, True),
        TypedDictAttribute("time", Type.str, True),
        TypedDictAttribute("region", Type.str, True),
        TypedDictAttribute("resources", TypeSubscript(Type.List, [Type.str]), True),
        TypedDictAttribute("detail", CloudwatchEventDetailTypeDef, True),
    ],
)

[vemel]

I made some changes toServicePackageParser, so it is more refactoring-friendly now. Please let me know if you have time for a pull request.

[xquek]

hi vemel, thanks for the pointers! i will have time for a PR this week - but it looks like you already have the implementation above and i dont want to slow you down.

I can work to improve metricStat if you want to merge what you already have above.

Or if you dont mind waiting, i should be able to get them out in the next few days.

Thanks!! let me know!

[vemel]

I definitely do not mind waiting, it is not an urgent change. Take your time.

Once again, if you are stuck - please let me know.

[vemel]

@xquek Hello! Do you have any updates?

[xquek]

hi @vemel sorry for the wait. Work been busy. I put out a draft PR at https://github.com/youtype/mypy_boto3_builder/pull/233

While implmenting, i realised the cloudwatch notification for event bridge has lots of nested structs and different example. Maybe it might be reasonable to use Type.DictStrAny as you had in your example above.

Also can i check - there are some fields that are enums values, currently i have use type.str - let me know if i using Literal is preferred. Thanks!

[vemel]

Thank you for your contribution. I added your TypeDefs to cloudwatch service stubs. Please let me know if it works for you.