Image via Arnaud Lapierre
Testing your new release or database migrations should always be done on a system that is as similar to your production environment as possible. Keeping the codebase and configuration synced between production and staging is straightforward on most systems, but keeping the data up to date can be a hassle.
Heroku provides some great tools to mirror your production data to your staging database. We will give you a quick guide on how to set this up with Heroku and their scheduler add-on. This guide is currently targeted at Rails apps on Heroku, as Ruby and the Heroku Gem are necessary to perform the backup actions.
As long as your database is small enough you can do this during your deployment with Codeship. We will show you in the first step how to set this up. As your database becomes larger this step may take too long for every deploy and you will want to do this on a regular schedule. The second part of the blog post will show how you can set this up as well.
For smaller production databases you might do well with a dev database for your staging environment. But as it has a limit of 10.000 lines you might have to upgrade to the basic plan at $ 9 per month as soon as your database grows. Being sure your data migrations work well on every deployment is definitely worth the $ 9! You can read more about the Heroku databases and how to get started in their Dev Center Article
Sync database on every deployment to staging
With the Codeship it is really easy to copy your production database into staging before every deployment. In your heroku staging deployment just add the name of your production app into the restore_from field.
It will then do a backup of the production db and restore it into the staging application. This can take a while for larger deployments though.
Sync in regular intervals for bigger databases
You have to start by adding the Heroku Gem to your Gemfile. This is necessary as Heroku currently doesn’t provide their heroku command on their virtual machines. Next you will need to add your Heroku API Key to the heroku config of your staging application so the Gem can authenticate. You can find your API key on your account page.
heroku config:add HEROKU_API_KEY=YOUR_API_KEY
Next add the following script to your codebase. Please change the placeholders for your production and staging apps to the actual names of your app. You can put the script in script/database_copy.sh for example
heroku pgbackups:capture --expire --app YOUR_PRODUCTION_APP_NAME heroku pgbackups:restore DATABASE `heroku pgbackups:url --app YOUR_PRODUCTION_APP` \ --app YOUR_STAGING_APP --confirm YOUR_STAGING_APP
Now you need to add the Heroku Scheduler add-on and go to the web page to run cron jobs on Heroku.
heroku addons:add scheduler heroku addons:open scheduler
In your scheduler just add bash scripts/database_copy.sh as a task and set the time it should run at.
Whenever you want to copy your production to your staging app you can also just run
heroku run bash scripts/database_copy.sh
It is vitally important for your business to be sure that any change to your application or data model doesn’t impact your customers and business. Being able to test on staging and having an easy way to reset staging at all times gives you the additional security when you push new code daily.