Upgrading to the latest version of the Ruby on Rails app can feel like navigating a maze of deprecation warnings, gem conflicts, and the dreaded "it works locally but not in production" surprises. If you’ve ever felt overwhelmed by the process, you’re not alone. I’ve been there too. But with a clear plan and a systematic approach, it doesn’t have to be a nightmare.
Here’s a step-by-step guide to help you upgrade your Rails app with confidence.
Step 0: Prepare a Degradation Test
Before diving into the upgrade, you need a safety net. A degradation test is a combination of automated and manual tests that ensure your app’s critical functionality remains intact after changes.
If you already have a robust test suite, you’re in good shape. If not, focus on creating manual tests for your app’s core features. Document step-by-step processes to verify key functionalities like user authentication, payment processing, or data exports. These tests will save you time and stress during the upgrade process.
Step 1: Refer to the Official Rails Upgrade Guide
The Rails upgrade guide is your best friend during this process. It provides version-specific advice and highlights breaking changes that could impact your app.
Grab a coffee ☕️ and read through the documentation carefully. Create a checklist of changes you need to make and note anything you don’t fully understand. This step might feel overwhelming at first, but it’s worth the effort. Understanding the changes will help you troubleshoot issues and update your code with confidence.
Step 2: Tackle Deprecation Warnings
Deprecation warnings are Rails’ way of telling you that certain features or methods will be removed in future versions. While they don’t break your app immediately, ignoring them can lead to problems down the road.
Start by fixing these warnings.
Step 3: Update Your Gems
Upgrading Rails often requires updating your gems to resolve dependency conflicts. Instead of blindly running bundle outdated, I recommend a more strategic approach:
Create a Test Branch: Start by creating a new branch for the upgrade to avoid disrupting your main codebase.
Update Rails First: Change the Rails version in your
Gemfileand runbundle update rails. This will likely trigger dependency conflicts, which is normal.List Conflicting Gems: Review the errors and make a list of gems causing conflicts.
Update Gems Incrementally: Update each gem in a separate branch, testing as you go. Some gems may only work after the Rails upgrade, so note those for later.
Pro Tip: Instead of manually verifying each gem, you can try using RailsUp, a gems compatibility checker tool to check gem compatibility across different Rails versions and get the complexity score to upgrade.
Step 4: Update the Rails Version
Once you’ve resolved gem conflicts, it’s time to update the Rails version. Run bundle update rails to ensure your app is using the latest version specified in your Gemfile.
Step 5: Run rails app:update
The rails app:update command is a handy tool that updates configuration files and generates new ones to align with the latest Rails version. However, you’ll need to manually adjust the code to fit your app’s specific needs.
Before running this command, visit RailsDiff to see the differences between your current Rails version and the one you’re upgrading to. This will help you prepare for the changes.
Pro Tip: Running this command might update the load_defaults version in config/application.rb. You don’t have to update this setting immediately.
Step 6: Update Your Code
After upgrading Rails, some parts of your codebase may rely on deprecated behaviors. Use the checklist you created in Step 1 to identify and update these areas.
Additionally, some gems may require code adjustments after the Rails upgrade. Refer to your list from Step 3 and test these changes thoroughly.
Run your test suite after each update to catch regressions early. If your test coverage is limited, manually test critical workflows to ensure everything works as expected.
Step 7: Test, Test, Test
Testing is the final and most crucial step in the upgrade process. It’s your last line of defense against unexpected issues.
Run Your Automated Tests: These will quickly identify broken functionality caused by the upgrade.
Conduct Manual Testing: Use your degradation tests to verify critical features like payments, form submissions, and reports.
Test in a Staging Environment: Deploy your upgraded app to a staging environment that mirrors production. This helps catch environment-specific issues.
Monitor Post-Deployment: Even with thorough testing, surprises can happen in production. Monitor logs and user reports closely, and have a rollback plan ready.
Wrapping Up
Upgrading a Rails app doesn’t have to be overwhelming. With a clear plan, incremental updates, and thorough testing, you can minimize risks and ensure a smooth transition. Each upgrade strengthens your app’s foundation and boosts your confidence as a developer.
So, take a deep breath, follow these steps, and tackle that Rails upgrade like a pro!