Hello World

SRE interview assignment for Cointracker

Overview

This is a simple Python/Flask "Hello World" app

Built using Docker and pushed to Google Container Registry

Includes Terraform configs which create Cloud Run and Cloud Build resources in GCP, which in turn deploy the app and enable CI/CD

Architecture / Components

This repo contains the following:

• Python app that uses Flask to respond to HTTP requests
• Dockerfile to containerise the Flask app
• Terraform code that implements the Google Cloud provider configure and initially deploy the container to Cloud Run
• Terraform code that creates a Cloud Build trigger, which watches commits to this repo and triggers deploys
• Cloudbuild config for building the container, pushing to Google Container Registry and deploying the container to Cloud Run (upon commits to the main branch)

Design Motivations

• I felt it was appropriate to use Docker in order to maintain parity between dev and prod, it allowed for rapid local testing and deployment
  
• Google Cloud Run was selected as a container runtime as it's simple and quick to implement and fits well with Cloud Build and GCR
  
• Terraform was used for the IaC aspect as I feel the Google Cloud TF provider is quite well maintained and exceptionally well documented

Potential Improvements

• Unit Testing for Flask app and add a testing step in the Dockerfile
• GCP Service Accounts and IAM bindings/roles could have been used in a more granular fasion, but are fine for the purposes of this simple app
• Implement a Makefile to faciliate local execution/testing and to faciliate pushing containers to GCR
• A custom domain could be added (via Terraform) to bind the Cloud Run URL to something more apt
• Cloud Build status checks/badges could be displayed in this README to show build status

Local Testing

docker build -t helloworld:latest . 
docker run -d -p 5000:5000 hello-world:latest

Pushing to Google Container Registry

docker tag helloworld:latest gcr.io/cointracker-379915/helloworld:latest
docker push gcr.io/cointracker-379915/helloworld:latest

You may need to subsitute the GCP project name above (eg. cointracker-379915) to your own

Terraform Usage

cd tf
terraform init
terraform apply

CI/CD Pipeline

Commits to the main branch will trigger a Cloud Build job that will build the container and deploy it to Cloud Run

Cloud Run URL

Hello World Flask app hosted in Google Cloud Run