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Deploy Ruby on Rails on Heroku

codinghall profile image codinghall ・6 min read

My first deployment with Heroku did not go as smoothly as I anticipated. I decided to document and share my Heroku journey. I can only share some of the hurdles from my Plan My MD Visit app. Previously, the project was built and completed by running 'http://localhost:3000/'. My recommendation to fellow developers would be to deploy early and debug as you progress through the project. It is more time efficient than discovering a large number of glitches near the end of the project.

First things first

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Sign Up with Heroku.

It provides free cloud services for developers to run their applications. Make sure you read their provisions for their free platform services.

SQLite > PostgreSQL

If your application is currently running on SQLite database, there are two action items:

Gemfile and SQL query in PostgreSQL.

Gem sqlite3 will be decommissioned, and replaced by gem pg.

# gem 'sqlite3', '~> 1.4'
gem 'pg'
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Run bundle install.

We will circle back to SQL query in PostgreSQL.

Update config/database.yml

This file was created by default when we initiated the Rails app with $ rails new app-name. Rails provides a database with sqlite3 adapter, and its pre-built code as follows:

# SQLite. Versions 3.8.0 and up are supported.
#   gem install sqlite3
#   Ensure the SQLite 3 gem is defined in your Gemfile
#   gem 'sqlite3'
default: &default
  adapter: sqlite3
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000

  <<: *default
  database: db/development.sqlite3

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
  <<: *default
  database: db/test.sqlite3

  <<: *default
  database: db/production.sqlite3
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We need to adjust it for postgresql. While perusing Heroku documentation and GitHub gist, I was able to revise my code in config/database.yml.

# PostgreSQL. Versions 8.2 and up are supported.
# Install the pg driver:
#   gem install pg
# On Mac OS X with macports:
#   gem install pg -- --with-pg-config=/opt/local/lib/postgresql84/bin/pg_config
# On Windows:
#   gem install pg
#       Choose the win32 build.
#       Install PostgreSQL and put its /bin directory on your path.
# Configure Using Gemfile
# gem 'pg'
  adapter: postgresql
  encoding: unicode
  database: app-name_development
  pool: 5
  username: your_username

  # Connect on a TCP socket. Omitted by default since the client uses a
  # domain socket that doesn't need configuration. Windows does not have
  # domain sockets, so uncomment these lines.
  #host: localhost
  #port: 5432

  # Schema search path. The server defaults to $user,public
  #schema_search_path: myapp,sharedapp,public

  # Minimum log levels, in increasing order:
  #   debug5, debug4, debug3, debug2, debug1,
  #   log, notice, warning, error, fatal, and panic
  # The server defaults to notice.
  #min_messages: warning

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
  adapter: postgresql
  encoding: unicode
  database: app-name_test
  pool: 5
  username: your_username
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This is important. git push, and always try to maintain latest repo files in your GitHub account.

Heroku CLI

Follow the initial Heroku CLI setup. Once installed, you can type $ heroku login on the terminal. You will receive a return feedback as displayed below.

$ heroku login
$ heroku: Press any key to open up the browser to login or q to exit:
$ Opening browser to
$ Logging in... done
$ Logged in as
$ ...
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It will then navigate you to Heroku web browser to log in. You may close the web page after you successfully log in, and return to VSCode terminal. With heroku command prompt, you will see Heroku Command Line Interface.

$ heroku 
    CLI to interact with Heroku

      heroku/7.47.11 darwin-x64 node-v12.16.2

      $ heroku [COMMAND]

      access          manage user access to apps
      addons          tools and services for developing, extending, and operating your app
      apps            manage apps on Heroku
      auth            check 2fa status
      authorizations  OAuth authorizations
      autocomplete    display autocomplete installation instructions
      buildpacks      scripts used to compile apps
      certs           a topic for the ssl plugin
      ci              run an application test suite on Heroku
      clients         OAuth clients on the platform
      config          environment variables of apps
      container       Use containers to build and deploy Heroku apps
      domains         custom domains for apps
      drains          forward logs to syslog or HTTPS
      features        add/remove app features
      git             manage local git repository for app
      help            display help for heroku
      keys            add/remove account ssh keys
      labs            add/remove experimental features
      local           run Heroku app locally
      logs            display recent log output
      maintenance     enable/disable access to app
      members         manage organization members
      notifications   display notifications
      orgs            manage organizations
      pg              manage postgresql databases
      pipelines       manage pipelines
      plugins         list installed plugins
      ps              Client tools for Heroku Exec
      psql            open a psql shell to the database
      redis           manage heroku redis instances
      regions         list available regions for deployment
      releases        display the releases for an app
      reviewapps      manage reviewapps in pipelines
      run             run a one-off process inside a Heroku dyno
      sessions        OAuth sessions
      spaces          manage heroku private spaces
      status          status of the Heroku platform
      teams           manage teams
      update          update the Heroku CLI
      webhooks        list webhooks on an app
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There are a few ways to create a Heroku app, either from Heroku CLI or web browser. With the CLI, you can create a new Heroku app with $ heroku create. This prompt gives you the default Heroku-20 stack. It depends on your Ruby buildpack, and Heroku-20 did not align with my project build. I reviewed Heroku stacks documentation, and found Heroku-18 stack worked with my Ruby version 2.6.1.

Heroku Database

Once Heroku app is successfully created, we can push the code to the Heroku server with command line $ git push heroku master. At this point, if you still hit a snag, I highly recommend Google search — lots of Stack Overflow and tutorials from other devs. For my project, it successfully deployed.

$ heroku run rails db:migrate
$ heroku run rails db:seed
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As we are migrating our database to Heroku's PostgreSQL, we need to initiate the command lines above. heroku run rails db:seed is necessary when you have seeding data, either fetching API data or manual seeds.rb.

PostgreSQL - JOIN clause

Circling back to SQL query in PostgreSQL, this part frustrates me the most. At one point, I hit an impasse, and thought my deployment process was fully corrupted. My application was up and running. However, as I was navigating all links and forms, I was not able to proceed with a few form selections. Heroku's error notification did not provide with enough detailed information to understand what was wrong.

We're sorry, but something went wrong.
If you are the application owner check the logs for more information.

I gave up that night, slept and continued debugging the next day. 😥

After spending a few hours on Stack Overflow, I learned that my SQL query on helper methods needed refactoring following PostgreSQL. I suggest reviewing all query statements to PostgreSQL query documentation. One debugging example for the JOIN query.

# SQLite query on JOIN
def self.doctors 

# PostgreSQL query on JOIN
def self.doctors 
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Last hurdle was on migrating PROVIDER_CLIENT_ID and PROVIDER_SECRET from .env to Heroku. In Heroku browser, you can navigate to your app > Settings > Config Vars > Reveal Config Vars.

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This concludes the journey of my first RoR deployment with Heroku.

I intend to exploring future project builds with Heroku, and share my experience with other devs. Thank you, Heroku. 👾

Drum roll.... 🥁

Below is my first Ruby on Rails deployment on Heroku!

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Post Scriptum:

I am currently enrolled in Flatiron's part-time Software Engineering program, and have decided to blog my coding journey. I believe one of the catalyst to becoming a good programmer is to welcome constructive criticism. Feel free to drop a message. 🙂

Keep Calm, and Code On.

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