[Cialug] Python Question

[Shane Nehring]

Yeah, per https://docs.aws.amazon.com/lambda/latest/dg/python-handler.html
it's usually a dict. Barry brings up a good point though, unless something
upstream of your code is doing some checking you'll probably want to add
that in your handler for whatever data decodes to. I recently fell in love
with pydantic when working with fastapi, you could look into that.

On Wed, Sep 13, 2023 at 9:36 AM Barry Von Ahsen <vonahsen at gmail.com> wrote:

> The event parameter is defined as an event object, which is a JSON document
>
>
> https://docs.aws.amazon.com/lambda/latest/dg/gettingstarted-concepts.html#gettingstarted-concepts-event
>
> I'd _hope_ there were a bit more error checking to verify that fact, or a
> more strongly-typed method declaration, but that's just me :)
>
>
> -barry
>
>
>
>
> > On Sep 13, 2023, at 09:25, Todd Walton <tdwalton at gmail.com> wrote:
> >
> > I have a Python question. I've written (copy/pasted really) a bit of
> Python
> > code to run in AWS Lambda. It's triggered by AWS CloudWatch Logs. The
> input
> > from CloudWatch is a string like this:
> >
> > {
> >  "awslogs": {
> >    "data": "H4sIAAAAAAAAAHWPwQqCQBCGX0Xm7EFtK+smZBEUg..."
> >  }
> > }
> >
> > And the relevant bit of Python code looks like this:
> >
> > def lambda_handler(event, context):
> >  encoded_zipped_data = event['awslogs']['data']
> >  zipped_data = base64.b64decode(encoded_zipped_data)
> >  data = gzip.decompress(zipped_data)
> >  response =
> >
> client.publish(TopicArn='arn:aws:sns:us-east-1:xxxxxx:log-error-topic',Message=json.dumps(data.decode('utf-8'),
> > indent=3))
> >
> > So... I understand that the input string is fed into the Python function
> as
> > the "event" argument, and then the first line -- the "encoded_zipped_data
> > =" part -- reads that string and accesses the "data" element.
> >
> > But how does Python know how to treat that string as an object with
> > sub-elements? I would expect that I would have to convert the string to
> > JSON first. But Python just knows? What am I not understanding here?
> >
> > --
> > Todd
> > _______________________________________________
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