Heroku Deployment

Debugging Deployment Issues

Earlier this week, I built and deployed a self-destructing message application, a clone of TMWSD. I built it in Rails, with a tiny bit of JavaScript to power a fun, copy to clipboard feature. Since I planned on deploying it via Heroku, I incorporated PostgreSQL from the beginning. That likely saved me a lot of trouble when it came to deployment. But I figured writing a how-to as reference for future deployments on Heroku would still be valuable.

Heroku has several guides on deployment, including one on deploying with Git, which I chose. My app was in a subfolder of my original repository, so I made sure to navigate into that subfolder and initialize a Git repository there. I also installed the Heroku command line tools with brew install heroku/brew/heroku.

Then, I used the heroku create CLI command to create a new repository on Heroku. (At this point, I also set up an account on Heroku, as I was prompted to enter my email and password to proceed via the command line). And then git push heroku master to push my code to the Heroku remote. Up until this point, things went fairly well. I was able to run git remote -v and confirm that Heroku was set up as a remote based on the output. And the build proceeded as expected, without any fatal errors, after the git push command.

But my application still wasn’t live. To debug, I checked out the activity logs available on the Heroku dashboard. These were enormously helpful in debugging, as they provide fairly decent error codes. I also jumped over to another guide available on Heroku’s site, which is specific to deploying a Rails 5.x application.

After reading about the error code, and looking through the Rails-specific guide, I realized my database needed additional work. Even thought I had specified adapter: postgresql for production in config/database.yml I still needed to migrate my production database by running heroku run rake db:migrate. Unfortunately, the migration failed with the message 'production' database is not configured. First, I went back and reconfigured my config/database.yml so it looked more like the one presented in the Heroku Rails guide. Next, I attached my credentials to the application by using the addons:attach command presented here. To do this, I needed to find the database name, which you can snag with the command heroku addons or you can snag it from the Heroku dashboard. I also needed to input the Heroku generated application name, which I found on my dashboard. The final command looked like this: heroku addons:attach heroku-database-name-here --credential default -a heroku-app-name-here.

According to the Heroku documentation, this accomplishes the following:

If no other Heroku Postgres exist as part of the application that the database is being attached to, the credential will be assigned to the DATABASE_URL config var. If DATABASE_URL already exists on the application, the credential will be attached to the application using the format HEROKU_POSTGRESQL_[COLOR]_URL.

After this, I used the heroku config command in the CLI to see my application’s config vars. Then, in my application’s config/database.yml I added a line to associate the credentials with my application: url: <%= ENV['HEROKU_POSTGRESQL_[COLOR]_URL'] %>. I committed this update prior to git push heroku master and then successfully ran heroku run rake db:migrate.

And then, I celebrated my success by sending self-destructing messages to all my friends! Including this one…she hasn’t read it yet….