AWS Serverless Application

This project is an AWS Serverless application built using AWS SAM, Python, and Poetry for dependency management. It includes Lambda functions with shared layers and automated local packaging.

Project Structure

aws-serverless-app/
│
├── layers/                      # Contains shared layers for Lambda functions, with dependencies installed directly in each layer directory.
│   ├── shared_layer_one/
│   │   ├── __init__.py
│   │   ├── utils_one.py
│   ├── shared_layer_two/
│   │   ├── __init__.py
│   │   ├── utils_two.py
│
├── src/                         # Contains Lambda function source code.
│   ├── my_lambda/
│   │   ├── __init__.py
│   │   ├── handler.py
│   ├── another_lambda/
│   │   ├── __init__.py
│   │   ├── handler.py
│
├── api/                         # OpenAPI specification (if using API Gateway).
│   └── openapi.yaml
├── build_artifacts/             # Directory for storing locally packaged Lambda ZIP files.
│
├── .env                         # Environment variables for local development.
│
├── .gitignore                   # Ignore files for Git
│
├── Makefile                     # Automates build, package, and test tasks.
│
├── template.yaml                # SAM template for defining the serverless application.
│
├── pyproject.toml               # Poetry configuration file for managing dependencies
│
├── README.md                    # Documentation for the project
│
└── tests/                       # Unit tests for Lambda functions and layers
    ├── layers/
    │   ├── test_shared_layer_one.py
    │   ├── test_shared_layer_two.py
    ├── test_my_lambda.py
    └── test_another_lambda.py

Prerequisites

• Python 3.9
• Poetry
• AWS SAM CLI
• Make
• Docker

Setup

1. Install dependencies:

   make install

2. Install Lambdas and Layers dependencies:

   make deps

3. Build the application:

   make build

4. Package the application using SAM package into an S3 bucket:

   make sam-package

5. Package build artifacts into ZIP files:

   make package

6. Run the application locally:

   make local

7. Run tests:

   make test

8. Clean up build artifacts:

   make clean

Adding New Dependencies

Adding Dependencies to a Specific Lambda Function

• Use the following command to add a new dependency to a specific Lambda function (e.g., my_lambda). This will automatically update the pyproject.toml file:

  poetry add --group my_lambda <dependency-name>

  For example, to add requests to my_lambda:

  poetry add --group my_lambda requests

Adding Dependencies to a Specific Layer

• Use the following command to add a new dependency to a specific layer (e.g., shared_layer_one). This will automatically update the pyproject.toml file:

  poetry add --group shared_layer_one <dependency-name>

  For example, to add boto3 to shared_layer_one:

  poetry add --group shared_layer_one boto3

Notes

• Dependencies for both the application and layers are managed using Poetry.
• The Makefile dynamically handles the installation of dependencies for each Lambda and layer.
• Adding new Lambdas or layers requires minimal changes—just add the source files and dependencies to pyproject.toml.