Build AWS Lambda Layer zip file for Python Dependancies

Creates an AWS Lambda Layers zip file that is optimized for: Lambda Layer directory structure, compiled library compatibility, and minimal file size.

This function was created to address these issues:

• Many methods of creating Lambda zip files for Python functions don't work for Lambda Layers
  • This is due to the fact Lambda Layers require specific library paths within the zip, unlike regular Lambda zip files
• Compiled dependancies must be created in an environment that matches the Lambda runtime
• Reduce size of zip file by removing unnecessary libraries and files

Note: This script requires Docker and uses a container to mimic the Lambda environment.

Features

• Builds zip file containing Python dependancies and places the libraries into the proper directory structure for lambda layers
• Ensures compiled libraries are compatible with Lambda environment by using docker container that mimics the lambda runtime environment
• Optimized the zip size by removing .pyc files and unnecessary libraries
• allows specifying lambda supported python versions: 2.7, 3.6, 3.7 and 3.8
• Automatically searches for requirements.txt file in several locations:
  • same directory as script
  • parent directory or script (useful when used as submodule)
  • function sub-directory of the parent directory

Installation

This function can be cloned for standalone use, into a parent repo or added as a submodule.

Clone for standalone use or within a repo:

# If installing into an exisiting repo, navigate to repo dir
git clone --depth 1 https://github.com/robertpeteuil/build-lambda-layer-python _build_layer

Alternatively, add as a submodule:

cd {repo root}
git submodule add https://github.com/robertpeteuil/build-lambda-layer-python _build_layer
# Update submodule
git submodule update --init --recursive --remote

Use

• Run the builder with the command ./build_layer.sh
  • or _build_layer/build_layer.sh if installed in sub-dir
• It uses the first requirements.txt file found in these locations (in order):
  • same directory as script
  • parent directory of script (useful when used as submodule)
  • function sub-directory of the parent directory (useful when used as submodule)
• Optionally specify Python Version
  • -p PYTHON_VER - specifies the Python version: 2.7, 3.6, 3.7, 3.8 (default 3.7)

Reference - remove submodule

If installed as submodule and need to remove

# Remove the submodule entry from .git/config
git submodule deinit -f $submodulepath
# Remove the submodule directory from the superproject's .git/modules directory
rm -rf .git/modules/$submodulepath
# Remove the entry in .gitmodules and remove the submodule directory located at path/to/submodule
git rm -f $submodulepath
# remove entry in submodules file
git config -f .git/config --remove-section submodule.$submodulepath