Updating a RoR 4.28 app to 6.1

rubyonrails-talk
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Hi everyone, I have an old app that is currently in 4.2.8 and hosted on Heroku. I plan to get it updated to 6.1 On Heroku it is on a stack that is end of life. There are some new changes required that have some new tables and relationships to be setup So far I have created a new app on Heroku and managed to backup and restore the database to the new app. I’m a bit daunted by how to upgrade my old app and point it to the new Heroku App. The app is fairly simple, mostly CRUD features for a membership application. If anyone has any thoughts or can assist I would be most grateful Regards, Dave

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Doesn’t matter what you’re updating to, the procedure I follow is the same:

  1. Increase test coverage (measured using simplecov) as high as possible.
  2. Upgrade 1 minor version at a time, running/fixing the code as we go along, till we hit the desired version.

If you’d like more help, feel free to respond and we’ll work something out.

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Thanks Hasan, When you say 1 minor version at a time, do you mean major (as in 4 to 5, then 6) - there are a lot of minor version :slightly_smiling_face: Dave

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Yes… do it slowly and methodically. This is how you ensure reliability.

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OK thanks - I’ve actually just switched Mac’s and it has taken a lot of time to get the new machine configured and the app running. So just now the server runs and I can login to it! So all good for now, I’ll make my changes in 4.2.8 and then move forward later to upgrade the RoR version. Thanks for chipping in! Dave

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Should you need assistance, this is the sort of thing that won’t take me too long to sort out, do feel free to reach out – hasandiwan@gmail.com. Cheers! – H

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I will certainly do that - thanks so much… Dave

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While I agree with Hassan, I think sometimes it might make sense to do one big version jump (e.g. from Rails 4.2 to 6.1) – I only recommend this for very small applications that are a simple CRUD app.

My co-worker wrote about a couple of strategies in this article: Two Commonly Used Rails Upgrade Strategies - FastRuby.io | Rails Upgrade Service

I think dual booting could be very helpful if you decide to start upgrading one minor version at a time: Getting Ready for Rails 6.0: How to Dual Boot - FastRuby.io | Rails Upgrade Service

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Hassan’s way may be thoroughly sensible - but one major version at a time has always worked for me in practice!

Getting decent test coverage is the critical part. If you can trust your tests - then it almost doesn’t matter how you go!

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Thanks for the follow up help & suggestions… I decided to leave the app on 4.2.8 for the time being. This is so I can implement new features & I will go back to upgrading once this is done. regards, Dave

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It does matter how you go, for the following reason.

If you upgrade from 4.2.8 to 4.2.9 and a test fails as a result, the delta of possible changes you must go through is much smaller than if you went from 4.2.9 to 6.1.4 directly. I place (perhaps too much) emphasis on reliability for a rails programmer, but I am who I am. – H