cdk-lambda-layer-builder is a collection of AWS CDK constructs to build Python Lambda Layers with minimum requirements on the user side, e.g. no bash or zip cli has to be available on the user's machine.
Amazon Lambda functions often require extra modules which can be packaged in an Amazon Lambda Layer. The Layer is then attached to the Lambda to make the packaged module easily usable in the function code. AWS CDK does not have a simple, production ready solution to create a Lambda Layer. This package solves this issue by providing a simple, yet powerful way to create Python Layers, where modules can come from PyPI or can be custom modules.
This construct works on Linux & MacOS and should work on Windows.
You need to install cdk-lambda-layer-builder in the python environment you intend
to use to build your stack. You can install the module directly from github with
$ python -m pip install git+https://github.com/aws-samples/aws-cdk-lambda-layer-builder.gitOr you can clone the repository first, then in the folder of this README.md, install
the module with
$ pip install .Here is a full example for creating a Lambda Layer with two modules available on
PyPI. The modules are NumPy
and Requests. Simply call the CDK construct
BuildPyLayerAsset and use its member variables (BuildPyLayerAsset.asset_bucket
and pypi_layer_asset.asset_key) to create the Lambda Layer resource. The layer
assets are built and packaged locally, within a Docker container. The standard
AWS packaging requirements
are used to create the asset:
from aws_cdk import Stack, aws_lambda, Duration
from constructs import Construct
from cdk_lambda_layer_builder.constructs import BuildPyLayerAsset
class BuildLambdaLayerStack(Stack):
def __init__(self, scope: Construct, construct_id: str, **kwargs) -> None:
'''
'''
super().__init__(scope, construct_id, **kwargs)
# create the pipy layer
pypi_layer_asset = BuildPyLayerAsset.from_pypi(self, 'PyPiLayerAsset',
pypi_requirements=['numpy', 'requests'],
py_runtime=aws_lambda.Runtime.PYTHON_3_8,
asset_bucket=asset_bucket
)
pypi_layer = aws_lambda.LayerVersion(
self,
id='PyPiLayer',
code=aws_lambda.Code.from_bucket(pypi_layer_asset.asset_bucket, pypi_layer_asset.asset_key),
compatible_runtimes=[aws_lambda.Runtime.PYTHON_3_8],
description ='PyPi python modules'
)
test_function = aws_lambda.Function(
self,
id='test',
runtime=aws_lambda.Runtime.PYTHON_3_8,
handler='main.lambda_handler',
code=aws_lambda.Code.from_asset('lambda_code'),
timeout=Duration.seconds(60),
layers=[pypi_layer],
retry_attempts=0,
)If you have some custom code, package it into a module (see cdk_lambda_layer_builder/test/lib/lib1
as an example) and use BuildPyLayerAsset.from_modules to build the Lambda Layer assets:
from aws_cdk import Stack, aws_lambda, Duration
from constructs import Construct
from cdk_lambda_layer_builder.constructs import BuildPyLayerAsset
class BuildLambdaLayerStack(Stack):
def __init__(self, scope: Construct, construct_id: str, **kwargs) -> None:
'''
'''
super().__init__(scope, construct_id, **kwargs)
# create a Lambda layer with two custom python modules
module_layer_asset = BuildPyLayerAsset.from_modules(self, 'ModuleLayerAsset',
local_module_dirs=['lib/lib1','lib/lib2'],
py_runtime=aws_lambda.Runtime.PYTHON_3_8,
)
module_layer = aws_lambda.LayerVersion(
self,
id='ModuleLayer',
code=aws_lambda.Code.from_bucket(module_layer_asset.asset_bucket, module_layer_asset.asset_key),
compatible_runtimes=[aws_lambda.Runtime.PYTHON_3_8],
description ='custom python modules lib1, lib2'
)
test_function = aws_lambda.Function(
self,
id='test',
runtime=aws_lambda.Runtime.PYTHON_3_8,
handler='main.lambda_handler',
code=aws_lambda.Code.from_asset('lambda_code'),
timeout=Duration.seconds(60),
layers=[module_layer],
retry_attempts=0,
)You can find an example of a full stack creating a Lambda function with a PyPI layer
and a custom module layer in cdk_lambda_layer_builder/test/app.py.
Test procedure:
- Clone the repo
- Deploy the CDK test stack
cdk-lambda-layer-builder/test/app.pyby runningcdk deploy - Go to
cdk-lambda-layer-builder/test/ - Run
pytest test_deployment.py - Run
cdk destroyto delete the resources created for the test