Running Rails / Sidekiq on Docker

This example is how to containerize a Ruby on Rails app running Sidekiq workers and connecting to PostgreSQL and Redis data stores.

Key files added or modified from default Rails app install

• myapp/docker-run.sh (example commands to start web and workers)
• myapp/Dockerfile
• myapp/bin/docker-entrypoint (added check for 'sidekiq' arg to toggle startup)
• myapp/config/database.yml (configured DB urls as env vars)
• myapp/config/sidekiq.yml (added test scheduled worker Hard Job)
• myapp/config/routes.rb (added /sidekiq dashboard route)
• myapp/.env (not committed to source control)

Example .env file contents

RAILS_ENV="production"
RAILS_MASTER_KEY="< YOUR KEY FROM myapp/config/master.key >"
DATABASE_URL="postgres://myapp:<YOUR_PASSWORD>@host.docker.internal/myapp_development"
REDIS_URL="redis://host.docker.internal:6379/0"
APP_NAME="myapp"
IMAGE_NAME="myapp" # TODO :version-tag

Running the app

1. Add necessary Docker files to existing repo
2. Configure correct Ruby/Rails version configs
3. Create .env file with correct values for above
4. Build and run containers in same directory as Dockerfile ...
   • Build image
     • docker build -t myapp .
   • Run containers
     • ./docker-run.sh (or enter each command separately in terminal)
   • Check whether running
     • docker ps
     • if app missing, docker ps -a, then check logs
       • docker logs myapp or docker logs myapp-worker
   • Test in browser (this test app example URLs)
     • http://localhost:3000/posts
     • http://localhost:3000/sidekiq
   • Shut down apps
     • docker stop myapp
     • docker stop myapp-worker
   • Remove containers (optional)
     • docker rm myapp
     • docker rm myapp-worker

Examples

Containers running locally

Web app

Sidekiq dashboard

Deploy to cloud

TODO

• /cloud-config folder with Terraform infra setup
• CI/CD to push images to container registry
• database migration
• traffic routing