Brainstorming approaches to reconcile Rails 8's default multi-DB setup with DATABASE_URL

rubyonrails-core
5

Yeah that seems to be in line with what the Rails guide and code say, if you explicitly provide a url:, it seems like it has the highest precedence. If you don’t provide a url but there is a (X_)DATABASE_URL env var present, then the env var subcomponents get merged on top of the components defined in yaml[1][2][3][4][5][6].

Yeah it is mildly ugly but I guess backwards compatibility trumps everything. When you start having multiple databases in your database.yml there is no way around a wordier database.yml with additional config. It gets even wordier by the way if you want to have multiple databases both in development and production :sweat_smile:: Best way to play around with Solid Queue in development? · Issue #332 · rails/solid_queue · GitHub.

I am wondering if we couldn’t have our cake and eat it too by introducing some syntactic sugar or helpers on top of database.yml to shorten default configuration for solid databases. For what they’re worth here are some random ideas:

  • url: <%= Rails.configuration.solid.cable_db_url %>

    as a shorthand for

    url: <%= URI.parse(ENV["DATABASE_URL"]).tap { |url| url.path += "_cache" } if ENV["DATABASE_URL"] %>

  • solid: true to do this

    cache:
  <<: *primary_production
  solid: true
queue:
  <<: *primary_production
  solid: true
...

    as a shorthand for this

    cache:
  <<: *primary_production
  url: <%= URI.parse(ENV['DATABASE_URL']).tap { |u| u.path += '_cache' } if ENV['DATABASE_URL'] %>
  migrations_paths: db/cache_migrate
queue:
  <<: *primary_production
  url: <%= URI.parse(ENV['DATABASE_URL']).tap { |u| u.path += '_queue' } if ENV['DATABASE_URL'] %>
  migrations_paths: db/queue_migrate
...

    I like this one because it could significantly reduce verbosity for a default Rails 8 setup, and you could still override it if needed.