Terraform AWS Scheduled Lambda Example 🛠

This is an example on how to make a Terraform setup to create a scheduled AWS Lambda which is called once an hour by AWS CloudWatch Event. The lambda function itself is made with TypeScript. The setup includes use of environment variables which are passed to the lambda function.

Setup 🪄

Install:

Node.js
AWS CLI
The Terraform CLI (1.2.0+)

Authenticate the Terraform AWS provider

Create Access Keys for your AWS IAM user (https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_access-keys.html)
Set IAM credential environment variables:
- export AWS_ACCESS_KEY_ID=<Your IAM user access key id>
- export AWS_SECRET_ACCESS_KEY=<Your IAM user secret access key>

Install dependencies

npm i

Required environment variables

Add a .env file at the lambda directory of the repo, by copying the .env.example file. Set values to the environment variables in the .env file

Deployment 🚚

cd lambda
npm run build
cd ../terraform
terraform init
env $(sed -e 's/^/TF_VAR_/' ../lambda/.env) terraform plan -out=terraform.plan
terraform apply terraform.plan

Cleanup 🧹

terraform destroy

Optional but Recommended - Use AWS S3 Bucket 🪣 to store Terraform state remotely

It is recommended that you store your terraform configuration state somewhere remotely especially when multiple people work together. The terraform_remote_state directory uses AWS S3 Bucket to store the state remotely unlike the terraform directory which only stores the state locally. To use remote state storing:

Create an S3 Bucket on your AWS account and change the bucket name in terraform_remote_state/main.tf file to match your bucket's name.
- Enable versioning for the Bucket, to easier rollbacks if needed.
Make sure all the people that need to be able to modify Terraform configuration have access to the remote state by adding the following IAM permissions for their IAM Users or Group:
- s3:ListBucket on arn:aws:s3:::YOUR_BUCKET
- s3:GetObject on arn:aws:s3:::YOUR_BUCKET/path/to/your/key
- s3:PutObject on arn:aws:s3:::YOUR_BUCKET/path/to/your/key
- s3:DeleteObject on arn:aws:s3:::YOUR_BUCKET/path/to/your/key
And of course, deployment from terraform_remote_state directory (cd ../terraform_remote_state instead of cd ../terraform)

Helpful Resources 🫡

https://registry.terraform.io/providers/hashicorp/aws/latest/docs
https://docs.aws.amazon.com/lambda/latest/dg/lambda-typescript.html
https://docs.aws.amazon.com/AmazonCloudWatch/latest/events/ScheduledEvents.html
https://esbuild.github.io/getting-started/#bundling-for-node

SamiOksanen/terraform-aws-scheduled-lambda