package

Lambda layer packaging implementation - Step 2 of the layer creation workflow.

This module handles the packaging phase of AWS Lambda layer creation, transforming the built dependencies into a properly structured zip file ready for deployment.

aws_lambda_artifact_builder.layer.package.move_to_dir_python(dir_site_packages: Path, dir_python: Path)[source]

Restructure installed packages into AWS Lambda layer format.

This function moves packages from a standard Python site-packages directory into the AWS Lambda layer’s required python/ directory structure. This transformation is necessary because different build tools (pip, Poetry, UV) install packages to different locations, but Lambda layers must follow a standardized directory layout.

Directory Transformation:

  • Source: build/lambda/layer/repo/.venv/lib/python3.x/site-packages/

  • Target: build/lambda/layer/artifacts/python/

The function handles the move operation safely by removing any existing target directory before moving to prevent conflicts and ensure clean packaging.

Parameters:

  • dir_site_packages – Path to the source site-packages directory from build process

  • path_pyproject_toml – Path to pyproject.toml file (determines project root and layout) to identify the correct layer artifacts directory

Raises:

FileNotFoundError – If the source site-packages directory doesn’t exist

aws_lambda_artifact_builder.layer.package.default_ignore_package_list = ['boto3', 'botocore', 's3transfer', 'urllib3', 'setuptools', 'pip', 'wheel', 'twine', '_pytest', 'pytest']

Default packages to exclude from Lambda layer zip files. These packages are commonly excluded because they are either:

  • AWS Runtime Provided: boto3, botocore, s3transfer, urllib3 are pre-installed in Lambda

  • Build Tools: setuptools, pip, wheel, twine are not needed at runtime

  • Development Tools: pytest, _pytest are testing frameworks not needed in production

Excluding these packages reduces layer size and avoids version conflicts with the Lambda runtime environment. Custom ignore lists can override this default.

aws_lambda_artifact_builder.layer.package.create_layer_zip_file(dir_python: Path, path_layer_zip: Path, ignore_package_list: list[str] | None = None, verbose: bool = True)[source]

Create optimized zip file for AWS Lambda layer deployment (Public API).

This function creates the final deployable artifact by compressing the layer’s python/ directory into a zip file with selective package exclusions. The resulting zip file is ready for upload to S3 and Lambda layer publication.

Compression and Optimization

  • Compression Level: Uses maximum compression (-9) to minimize layer size

  • Package Exclusions: Removes AWS runtime-provided and development packages

  • Directory Structure: Preserves Lambda-required python/ directory layout

  • Recursive Packaging: Includes all subdirectories and maintains file permissions

Default Exclusions:

The function automatically excludes common packages that are either provided by the AWS Lambda runtime (boto3, botocore) or not needed at runtime (pytest, setuptools). This reduces layer size and prevents version conflicts.

Output Location:

Creates build/lambda/layer/layer.zip in the project root, following the standard layer artifact naming convention established by the LayerPathLayout.

Parameters:

  • path_pyproject_toml – Path to pyproject.toml file (determines project root and output location)

  • ignore_package_list – Optional list of additional packages to exclude from zip. If None, uses default_ignore_package_list. Package names support glob patterns.

  • verbose – If True, shows detailed zip creation progress; if False, runs silently

class aws_lambda_artifact_builder.layer.package.LambdaLayerZipper(path_pyproject_toml: Path = REQ, layer_build_tool: LayerBuildToolEnum = REQ, ignore_package_list: list[str] | None = None, verbose: bool = True)[source]

Command class for Lambda layer packaging and zip file creation.

This class handles the second phase of Lambda layer creation: transforming build artifacts into a properly structured, compressed zip file ready for AWS deployment. It bridges the gap between different build tools by standardizing the packaging process regardless of whether dependencies were installed via pip, Poetry, or UV.

Packaging Workflow:

  1. Directory Standardization: Moves packages from tool-specific locations into Lambda’s required python/ structure

  2. Selective Compression: Creates optimized zip files with package exclusions for size optimization

  3. Deployment Preparation: Produces artifacts ready for S3 upload and Lambda layer publication

Multi-Tool Support:

  • pip: Uses packages already in correct python/ location (no movement needed)

  • Poetry: Moves from .venv/lib/python3.x/site-packages/ to python/

  • UV: Moves from .venv/lib/python3.x/site-packages/ to python/

Optimization Features:

  • Package Exclusions: Removes AWS runtime-provided packages (boto3, botocore) and development tools

  • Maximum Compression: Uses zip level -9 for smallest possible layer size

  • Custom Filtering: Supports additional package exclusions through ignore lists

Output Location:

Creates build/lambda/layer/layer.zip ready for deployment.

property path_layout: LayerPathLayout

LayerPathLayout object for managing build paths.