Why doesn't cloudformation support ZipFile inline code option for Python lambdas


The documentation for the ZipFile field in the AWS::Lambda::Function CloudFormation structure says that nodejs and Python are both supported. Copying the sample code for nodejs runtimes works just fine, but if you switch the Runtime to any Python runtime (Python3.7 up to Python3.11), the stack creation fails with:

Resource handler returned message: "Invalid request provided: The ZipFile attribute is not supported for the runtime 'Python3.7'" (RequestToken: <redacted>), HandlerErrorCode: InvalidRequest)

Is this an issue with the documentation (and Python runtimes no longer support inline ZipFile) or is there a defect in the CloudFormation process?

AWSTemplateFormatVersion: '2010-09-09'
      Type: AWS::Lambda::Function
        # Putting nodes18.x (instead of Python3.7, Python3.8, etc.) here works just fine..
        Runtime: Python3.7
        Role: !Sub "arn:aws:iam::${AWS::AccountId}:role/My_Role"
        Handler: index.handler
          ZipFile: |
            def handler(event, context):
              return {'statusCode': 200, 'body': 'OK'}
        Description: List Amazon S3 buckets in us-east-1.
          Mode: Active
asked 3 months ago411 views
1 Answer
Accepted Answer

Hi there,

You might have a typo , you have Python3.7 also python3.7 is no longer supported, to view the supported run-times, check this here

This is a template I just tried with python3.8 and it worked HTH

answered 3 months ago
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reviewed 3 months ago
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reviewed 3 months ago
  • Thank you so much for responding. That solved it! I wish the CF event errors were more descriptive. I jumped to python3.11.

  • Just for additional help, you could deploy cfn-lint that linter will pick up invalid values in your CFn template before you even deploy it. In this case it picked up the incorrect python in my IDE.


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