Can you have multiple database.yml files?

rubyonrails-talk
1

Hello! We have an internal gem for replicas, but we are working to migrate off of that to native Rails. Is it possible to have 2 different database.yml files (i.e. database.yml and database_old.yml) and conditionally load one based on an environment toggle? If yes, how/where would you tell Rails to load which YAML file? Thanks so much!

  • Rails version: 6.0.6.1
  • Ruby version: 3.0.6
2

Rails 6.1 has support for database switching. You would define multiple database settings in one database.yml tho. See Multiple Databases with Active Record — Ruby on Rails Guides for more info. If that doesn’t work for you, give the makara gem a try GitHub - instacart/makara: A Read-Write Proxy for Connections; Also provides an ActiveRecord adapter.

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3

It looks like I can do the following, and it seems to still work even in Rails 6: ruby on rails - Strategies for overriding database.yml? - Stack Overflow

4

Oh that’s interesting. But isn’t that for the whole application? Something I’ve done is when using a Rails engine, you can have it connect to a different database. So on Rails 6.1 you could define an initializer and do this

# engines/my_engine/config/initializers/database_connection.rb
Rails.application.reloader.to_prepare do
  MyEngine::ApplicationRecord.connects_to database: { writing: :my_engine, reading: :my_engine }
end

And make sure to define that :my_engine as a section in your database.yml for the parent app.

So I think you have several options here

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