Skip to content

README.md

Latest commit

 

History

History
53 lines (40 loc) · 1.79 KB

README.md

File metadata and controls

53 lines (40 loc) · 1.79 KB

CFN-CR-PythonLambdaLayer

CloudFormation Custom Resource that builds Lambda layers from pip requirements and/or inline Python source at stack deploy time — no S3 artefacts to upload first.

Quickstart

Deploy the builder stack once per region:

aws cloudformation deploy \
  --template-file CFN-CR-PythonLambdaLayer.yaml \
  --stack-name cfn-cr-python-lambda-layer \
  --capabilities CAPABILITY_IAM

Then declare a layer in any downstream stack, importing the ServiceToken for the target architecture (x86_64 or arm64):

MyDepsLayer:
  Type: Custom::LayerBuilder
  Properties:
    ServiceToken: !ImportValue "cfn:lambdalayer-x86-64:us-east-1:arn"
    Name: my-app-deps
    requirements: [requests, pydantic]

See CFN-CR-PythonLambdaLayer-SampleUsage.yaml for more examples.

Custom resource properties

Property Required Description
ServiceToken yes Builder Lambda ARN, via Fn::ImportValue.
Name yes Layer name.
requirements one of these two List of pip requirement strings.
filename + filecontent one of these two Inline Python module; filecontent is base64 (use Fn::Base64).
CompatibleRuntimes no Defaults to the builder's own runtime.
CompatibleArchitectures no Defaults to the builder's own arch. Override only for pure-Python layers.

Calling the x86_64 vs arm64 builder is how you pick the target architecture — C-extension wheels are installed on the builder's host arch, so they must match the consumer function's arch.

Limitations

Layers cap at 50 MB zipped / 250 MB unzipped; builder has 512 MB /tmp and a 15-min timeout. Delete is a no-op — clean up layer versions manually.

Contributions welcome: https://github.com/kisst/CFN-CR-PythonLambdaLayer/issues