Deploy simple Python web app via Docker and Terraform on Azure.

Plan

1. Create a very simple Python app
2. Write Dockerfile for packaging it
3. Local testing with with Docker Compose
4. Terraform
5. Build image and push to ACR
6. Deploy container

Bonus ideas:

• GitHub actions? ✅
• Releases? with tags ✅
• CI/CD pipelines? simple GitHub Actions workflow ✅

Time budget

Estimate was 10 h but completed in ~8 h

Biggest learnings

Terraform Shared Remote State

• This should be the default way of working
• You could let GitHub Actions use the remote state but you could also locally modify the infrastructure at the same time

Add empty backend

terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "4.59.0"
    }
  }

  backend "azurerm" {}
}

• Make sure backend is empty, since we pass the backend configs

Create Backends

# prod.tfbackend
resource_group_name  = "rg-terraform"
storage_account_name = "mytfstateacc"
container_name       = "tfstate"
key                  = "prod.tfstate"

• Create prod.tfbackend and dev.tfbackend for example

Create Resource Group

az group create --name rg-terraform --location switzerlandnorth

• Resource group for the storage account that will store the remote state

Create Storage Account and Container

az storage account create \
  --name mytfstateacc \
  --resource-group rg-terraform \
  --location switzerlandnorth \
  --sku Standard_LRS

az storage container create \
  --name tfstate \
  --account-name mytfstateacc

Initialize Terraform with a Backend

terraform init -backend-config="prod.tfbackend"

Working with Tags

• Very useful for simple CI/CD pipeline using GitHub actions
• Tags are a simple way of tracking software version (releases)

Create Tag

git tag v1.0.2

• You can tag a specific commit on any branch

Push Tag

git push origin v1.0.2

• This pushes the code marked by your tag to GitHub

Delete Tag

git tag -d v1.0.2

git push -d origin v1.0.2

Local Development Bind Mounts

docker run -it --rm --name mercury-api -p 8000:8000 -v $(pwd):/app mercury-app

• -v $(pwd):/app mounts the current working directory in the container's app directory
• This allows us to comment out the COPY . . in the Dockerfile during development
• Command already pretty verbose, Docker Compose cleaner