helloworld-overkill

Scope of this repo is to demonstrate a (not-so) simple deployment pipeline for a "hello world" web app.

Tech stack

Please find tech stack and tooling below:

• aws ECR
• aws ECS
• aws FARGATE
• aws IAM
• aws VPC
• bash
• curl
• docker
• flask
• gh
• github-changelog-generator
• jq
• pip
• Python3
• terraform v1.0

Usage

This repo is to showcase various common use-cases and standard practices when developing a web app, as well as demonstrating other relevant functionalities. Usage of basic commands:

• running a local docker registry and push built images to this local registry

  • run with docker run -d -p 5000:5000 --restart=always --name registry registry:2

• creating a hello world web app

  • created using Python3 and Flask in a virtual environment
  • run locally with flask run -p 8080
  • check functionality in browser @ http://localhost:8080

• creating a Dockerfile to allow for local building and testing of the application

  • build and push to local docker registry with ./build_and_push.sh helloworld-overkill v0.1.0 localhost:5000
  • test functionality with docker run --rm -p 8080:8080 localhost:5000/helloworld-overkill:latest
  • check functionality in browser @ http://localhost:8080

• creating cloud infrastructure

  • from ./terraform run terraform init
  • run terraform apply (Note: issue/14)

Tagging scheme

Chosen tagging scheme follows standard semantic versioning. Pre-prod app will be tagged v0.1.0 and will increase minor/patch version until production ready.

Deployment

Cloud provider of choice is AWS. To deploy we use terraform: after cloning the repo, it is required to set a profile named personal in ~/.aws/config with relevant credentials (Note: issue/16) and run terraform init from ./terraform folder.

Successively run terraform apply. Note it might take more than one attempt (Note: issue/14).

Ensure that the web app docker image is pushed to the relevant ecr repo: from project root run ./build_and_push.sh $ECR_REPO_URL

Once deployment is completed and tested, check functionality by accessing the ALB endpoint - manual for now, no test is present :(

Upon successful testing, tear down infra by running terraform destroy

Releases

NOTE: we use github-changelog-generator to automatically create releases, so below steps are relevant to facilitate automated changelog generation

Releases are based on a combination of multiple optional and non optional requirements:

• one or multiple commit being pushed and a tag created
  • required; we cannot create a release without changes
• milestones met
  • optional; we can create a milestone in advance to track issues and PRs or just create one for the purpose of creating a release, this applies only to facilitate automated changelog generation
• issues closed
  • optional; no need to close an issue to create a release
• Pull Requests closed
  • optional; no need to close PRs to create a release

Release Steps

Release process follow below steps:

• a tag is created and pushed:

  git tag -a $TARGET_VERSION -m "$TAG_MESSAGE" && git push --tags

• an issue is opened and closed in github with relevant release summary:

  gh issue close $(gh issue create -t "release target $TARGET_VERSION" -m "$TARGET_VERSION" -l release-summary -b $RELEASE_SUMMARY | tail -n1 | cut -d '/' -f7)

• full and delta changelogs are generated:

  ./generate_changelog.sh && ./generate_changelog.sh -d yes

• new release is created based on latest pushed tag

  ./release.sh

• new docker image is built

  ./build_and_push.sh helloworld-overkill $TARGET_VERSION

• commit updated CHANGELOG.md

• create new future milestone

    echo '{
      "title": "$FUTURE_TARGET_TAG",
      "state": "open",
      "due_on": "2022-12-31T23:59:59Z",
      "description": "Description foo bar"
    }' | gh createMilestone
  

Workarounds

• Manage milestones with gh (cli/cli#1200); relevant command:

  gh alias set --shell createMilestone "gh api --method POST repos/:owner/:repo/milestones --input - | jq '{ html_url: .html_url, state: .state, created_at: .created_at }'"