AWS Lambda deployment with Terraform & Terragrunt - Tutorial

NOTE: This code was written for an article in the RockedScience publication on Medium.

Description

This tutorial shows how to deploy a Python function on AWS Lambda with Terraform and Terragrunt.

The Terraform configuration can also:

• install the required Python dependencies
• keep track of changes to the code and dependencies to avoid re-deploying an unchanged function

Terragrunt is a wrapper for Terraform which helps to manage multiple environments.

Prerequisites

• Python 3.8
• Terraform v0.13.5
• AWS CLI 1.18.69
• Terragrunt v0.26.2 (optional)

Optional:

• Miniconda, Conda

Setup

• Create an AWS account and get a Access Key ID and Secret Access Key pair (read the docs)
• Install and configure the AWS CLI (read the docs)
• Install Terraform (read the docs)
• Install Python or, with Miniconda or Conda, run:

  $ conda env create -n tflambda -f environment.yml
  $ source activate tflambda
  

  (Python docs)
• Terragrunt is optional, install it for a more advanced setup (read the docs)

Usage

Running locally

$ cd lambda
$ pip install -r requirements.txt
$ python lambda.py

to view the log output on screen, run:

$ LOG_LEVEL=INFO python lambda.py

Deploying to AWS Lambda with Terraform

Run:

$ cd terraform
$ terraform init
$ terraform apply

If you have multiple AWS profiles and you want to set the profile to use:

$ AWS_PROFILE=myprofilename terraform apply

The Terraform AWS provider offers a number of options to set credentials, check the docs for further details.

To deploy to a specific AWS region (see variables.tf for defaults):

$ terraform apply -var aws_region="eu-west-1"

Deploying to AWS Lambda with Terragrunt

2 sample Terragrunt configurations are provided:

• terragrunt/eu sets the AWS region to eu-west-1
• terragrunt/us sets the AWS region to us-east-1

Run:

$ cd terragrunt/eu
$ terragrunt apply

change /eu to /us and repeat to try another region.

AWS profiles selection also applies to Terragrunt:

$ AWS_PROFILE=myprofilename terragrunt apply

Cleaning up

Run:

$ cd terraform
$ terraform destroy