Create AWS Step Function and Lambda using Terraform and GitLab CI

Install Terraform

• Download Terraform binary and unzip the package.

• Set terraform path to unzipped binary location. Terraform runs as a single binary named terraform. Any other files in the package can be safely removed and Terraform will still function.

• Verify the setup by using command terraform version in CLI.

Install AWS CLI

• Download and run the AWS CLI MSI installer for Windows (64-bit):

• To confirm the installation, open the Start menu, search for cmd to open a command prompt window, and at the command prompt use the aws --version command.

Build a infrastructure

• Create a directory for your configuration  mkdir terraform
• Change the directory and create a file main.tf.

• Initialize the directory with terraform init.

• Run terraform plan to see any changes are required for infrastructure.
• Format and validate the configuration
• Apply the configuration now with the terraform apply command.

Configuring Gitlab CI for Terraform

• Create a file on the root of your repository called .gitlab-ci.yml
• Get your access key ID and secret access key.
• Set aws variables go to - gitlab project → settings → CI/CD → Variables

Sample GitLab pipeline

stages:
  - validate
  - plan
  - apply
  - destroy
image:
  name: hashicorp/terraform:light
  entrypoint:
    - '/usr/bin/env'
    - 'PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin'
before_script:
  - export AWS_ACCESS_KEY=${AWS_ACCESS_KEY_ID}
  - export AWS_SECRET_ACCESS_KEY=${AWS_SECRET_ACCESS_KEY}
  - rm -rf .terraform
  - cd terraform/
  - terraform --version
  - terraform init

validate:
  stage: validate
  script:
    - terraform validate
  only:
    - branches

plan:
  stage: plan
  script:
    - terraform plan -out "planfile"
  dependencies:
    - validate
  artifacts:
    paths:
      - planfile

apply:
  stage: apply
  script:
    - terraform apply -input=false "planfile"
  dependencies:
    - plan
  when: manual
  only:
    - main

destroy:
  stage: destroy
  script:
    - echo "Destroying resources"
    - terraform destroy -state=$STATE --auto-approve
  dependencies:
    - apply
  when: manual
  only:
    refs:
      - main

Sample terraform code for lambda and step function