Deploy Rails on Heroku

Objectives

Deploy a Rails app to a production server using Heroku

Deploying a Rails app (like all things in Rails) is simple and magical.

Postgres

Heroku uses Postgres, so you should too. Or if you don't you should set it to be the DB for use in production.

Anywhere in Gemfile

gem 'pg', group: :production

bundle install --without production

Prepare for deployment

If you are using Rails 4 then you have to add the 12factor gem to your Gemfile in the production group.

Anywhere in Gemfile

gem 'rails_12factor', group: :production

This gem takes care of producing descriptive logs and serving your assets. Based on the recommended read: The Twelve-Factor App. Note that this class has covered many of these principles.

Bundle

Once this is done you have to run bundle which will automatically update the Gemfile.lock, which must be done before you push to Heroku. Be sure to commit your changes before pushing.

Pushing to Heroku

If you haven't already, download the Heroku toolbelt, which is a commandline tool used to interact with your heroku instance.

Create a heroku app

First you need to create a heroku app (if you haven't already). This can be done in the command line inside your project directory.

heroku create YOUR_APP_NAME_HERE

You can test that this worked by running git remote -v and you should see a new remote for heroku. If not try again (pay attention to any error messages).

Push it... p-p-p-push it real good

Once that is done we are ready to push our site to heroku. First, run git status to make sure you've added and commited all changes then we just push to the newly added heroku remote.

git push heroku master

(this will take a while to complete)

Production Database Setup

You can run any command on heroku by using heroku run followed by the command you want to execute. This will work for any command you'd normally run on your local development environment. This means that we can run rake db:migrate on the server.

migrate the database

heroku run rake db:migrate

You can also run db:reset or db:seed if you need to reset your database.

WARNING Once you've deployed, don't edit with your migration files. You'll end up with different DBs on your local and production servers and it'll be very difficult to debug. Instead, you should be a well behaved developer and add new migrations for any DB changes.

Configure environment variables

If your app depends on any environment variables (if you have a .env file) you'll need to set those values on Heroku.

To see the currently set environment values run

heroku config

To set a value run

heroku config:set TACO_KEY=xxxxxxx

Viewing your site

Once the push finishes you can go to your website. If you run heroku open it will automatically load your web browser at the appropriate URL.

Updating

Once everything is set up all you have to do is run git push heroku master to push new changes to Heroku (always make sure your changes are commited with git status).

Troubleshooting

What if something goes wrong?

From your project directory you can run heroku logs to see the rails console output on heroku or heroku logs --tail to see a live feed.

You can also type herkou run rails c to access the rails console on the production server.

Deploy - Rails