feat(event_sources): add CloudWatch dashboard custom widget event

[sthuber90]

Issue number: #1461

Summary

Changes

Please provide a summary of what's being changed

Added event mapping class for custom widget in CloudWatch dashboard

User experience

Please share what the user experience looks like before and after this change

With the new CloudWatchDashboardCustomWidgetEvent data class users have typed access to the event. The event will have custom parameters provided by the user in event.params["name"], event.raw_event["name"] and event["name"]. If the Lambda function is invoked with the describe parameter, the function should return its documentation. The describe parameter can be provided alone without the widgetContext being part of the event or as a custom param by the invoking user.

Checklist

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• Meet tenets criteria
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

Is this a breaking change?

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

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View rendered docs/utilities/data_classes.md

[codecov-commenter]

Codecov Report

Merging #1474 (41f8df5) into develop (a45a792) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop    #1474   +/-   ##
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  Coverage    99.89%   99.89%           
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  Files          123      124    +1     
  Lines         5498     5585   +87     
  Branches       629      634    +5     
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+ Hits          5492     5579   +87     
  Misses           2        2           
  Partials         4        4           

Impacted Files	Coverage Δ
...mbda_powertools/utilities/data_classes/__init__.py	100.00% <100.00%> (ø)
...es/data_classes/cloud_watch_custom_widget_event.py	100.00% <100.00%> (ø)

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[rubenfonseca]

Thank you so much! Looks pretty good! Just left a small comment to improve the docs, let me know what you think :)

[leandrodamascena]

Hello @sthuber90! This is an awesome PR, thanks a lot for taking the time to help improve the project!

I think it's missing a field domain in event source schema.. Using aws examples we can see the field domain in event source.

Could you please add this field?

[leandrodamascena]

Add the domain field.

[sthuber90]

@leandrodamascena I looked at the link you posted and in the cloudwatch-custom-widgets-samples repo but didn't find any domain (https://github.com/aws-samples/cloudwatch-custom-widgets-samples/search?q=domain). Furthermore, it's not mentioned in the official docs

Every call by a custom widget to Lambda includes a widgetContext element with the following contents, to provide the Lambda function developer with useful context information.

{
    "widgetContext": {
        "dashboardName": "Name-of-current-dashboard",
        "widgetId": "widget-16",
        "accountId": "012345678901",
        "locale": "en",
        "timezone": {
            "label": "UTC",
            "offsetISO": "+00:00",
            "offsetInMinutes": 0
        },
        "period": 300,
        "isAutoPeriod": true,
        "timeRange": {
            "mode": "relative",
            "start": 1627236199729,
            "end": 1627322599729,
            "relativeStart": 86400012,
            "zoom": {
                "start": 1627276030434,
                "end": 1627282956521
             }
        },
        "theme": "light",
        "linkCharts": true,
        "title": "Tweets for Amazon website problem",
        "forms": {
            "all": {}
        },
        "params": {
            "original": "param-to-widget"
        },
        "width": 588,
        "height": 369
    }
}

Can you please provide a link where the domain field is shown? And if we really want to add it, I think the AWS docs need to be updated as well.

[leandrodamascena]

Hi @sthuber90 - Answering your comments and questions:

Can you please provide a link where the domain is shown?

There isn't. I've notified the documentation team to include it.

I looked at the link you posted and in the cloudwatch-custom-widgets-samples repo but didn't find any domain

I should've been more explicit in what examples contained the domain field - I've found them after deploying the "Echo", "Hello world" and "Simple SVG pie chart" examples.

As we've encountered this issue before (missing schema and docs accuracy), I've deployed all of those examples to confirm whether domain field was present - it was.

---

Steps to reproduce:

1 - I chose the "Echo", "Hello World" and "SVG Pie Chart Example" examples here.

2 - As all the examples are cloudformation templates, I just clicked on the link and deployed it to my account.

3 - When the stack was complete I went to Lambda Function and added a print to the event variable inside the handler function.

4 - I used the dashboard created earlier just to generate logs a few times. After that I could see in the Cloudwatch Lambda Log Groups the domain field in the event.

[sthuber90]

Thank you for the clarification. I will add the field in the next days 👍

[sthuber90]

@leandrodamascena added domain field

[leandrodamascena]

@leandrodamascena added domain field

Hi @sthuber90!. I only removed a line in the example code and now it's ok to merge.

Thank you again.

It's ok.