Table of Contents

• Lambda Layer Multi-IaC Examples
  • Architecture
  • What's Included
  • Project Structure
  • Quick Start
    • Terraform
    • AWS SAM CLI
    • CloudFormation
  • Key Differences
  • Use Cases
  • Customization
  • Layer Management
  • Prerequisites
  • Security
  • License

Lambda Layer Multi-IaC Examples

The repository demonstrates how to create and manage AWS Lambda Layers using different Infrastructure as Code (IaC) tools. Each approach deploys the same infrastructure but uses different tooling and methodologies.

This example uses layer/requirements.txt to define Python dependencies for the layer. You can include PyPI packages, local packages (using relative paths), or any combination as requirements expand.

Architecture

┌─────────────────────┐
│   AWS Lambda Layer  │
│  (Python packages)  │
└──────────┬──────────┘
           │
           │ uses
           ▼
┌─────────────────────┐    ┌─────────────────────┐
│  Test Lambda Func   │◄───│    IAM Role         │
│  (test_lambda.py)   │    │ (execution role)    │
└─────────────────────┘    └─────────────────────┘

What's Included

• AWS Lambda Layer: Python dependencies packaged as a reusable layer
• Test Function: AWS Lambda function that uses the layer to validate functionality
• Three IaC Implementations: Terraform, AWS SAM CLI, and AWS CloudFormation

Note: Each implementation creates the same AWS resources but demonstrates different deployment workflows and state management strategies.

Project Structure

.
├── build_layer.sh            # Shared build script (Terraform & CloudFormation)
├── layer/
│   └── requirements.txt      # Python dependencies for the layer
├── lambda/
│   └── test_lambda.py        # Test Lambda function code
├── infra-terraform/          # Terraform implementation
│   ├── main.tf
│   ├── variables.tf
│   ├── outputs.tf
│   └── README.md
├── infra-sam/                # AWS SAM CLI implementation
│   ├── template.yaml
│   ├── samconfig.toml
│   └── README.md
├── infra-cloudformation/     # CloudFormation implementation
│   ├── template.yaml
│   └── README.md
├── dist/                     # Generated build artifacts (gitignored)
└── artifacts/                # ZIP packages (gitignored)

Quick Start

Choose your preferred IaC tool and follow the instructions:

Terraform

cd infra-terraform
../build_layer.sh  # Build dependencies first
terraform init
terraform plan
terraform apply

AWS SAM CLI

cd infra-sam
sam build          # SAM builds layer automatically
sam deploy --guided

CloudFormation

cd infra-cloudformation
../build_layer.sh  # Build dependencies first
aws cloudformation package --template-file template.yaml --s3-bucket your-bucket --output-template-file packaged-template.yaml
aws cloudformation deploy --template-file packaged-template.yaml --stack-name lambda-layer-cf-example --capabilities CAPABILITY_NAMED_IAM

Key Differences

Tool	Layer Building	Deployment	Resource Naming
Terraform	Manual (build_layer.sh)	Local state management	example-python-layer
SAM CLI	Automatic from requirements.txt	AWS CloudFormation backend	sam-example-python-layer
AWS CloudFormation	Manual + packaging	Native AWS service	cf-example-python-layer

Use Cases

• Terraform: Infrastructure teams preferring provider agnostic tool
• SAM CLI: Serverless-focused development with local testing capabilities
• CloudFormation: Native AWS tooling with existing AWS workflows

Customization

• Edit layer/requirements.txt to modify Python dependencies
• Update lambda/test_lambda.py to change the test function behavior
• Modify variables/parameters in each IaC tool's configuration files

Layer Management

Previous layer versions are not retained in these examples. Update retention settings according to your organization's policies. Configuration details are available in each tool's README.

Prerequisites

• AWS CLI configured with IAM permissions for Lambda, S3, and CloudFormation operations
  • Minimum permissions:

    {
      "Version": "2012-10-17",
      "Statement": [
        {
          "Effect": "Allow",
          "Action": [
            "lambda:*",
            "iam:CreateRole",
            "iam:DeleteRole",
            "iam:AttachRolePolicy",
            "iam:DetachRolePolicy",
            "iam:PassRole",
            "s3:*",
            "cloudformation:*"
          ],
          "Resource": "*"
        }
      ]
    }

• Python 3.12 (tested version)
• Required IaC tool: Terraform 1.13.4+, SAM CLI 1.138.0+, or AWS CLI 2.0+

Security

See CONTRIBUTING for more information.

License

This library is licensed under the MIT-0 License. See the LICENSE file.