Database connection parameters are tied to the filesystem

rubyonrails-core
1

HI Guys,

I recently tried VERY hard to override the database configuration bassed on ENV vars or actual API calls. This task is almost next to impossible.

I know that the database.yml file is parsed as ERB but that is sane for simple ENV replacement if you want to actually change which database adaptor it is (requires extra config/params) it becomes messy.

I found Database connection parameters are tied to the filesystem · Issue #5297 · rails/rails · GitHub which explains the issue/solution far better then I could.

Active record supports this natively, I can't see why rails would force the requirement of a database.yml and for it to have a "production" section. see establish_connection (ActiveRecord::Base) - APIdock URL section.

As I mentioned on the ticket, I would rather have ENV["DATABASE_URL"] supported as well, but I can't see how it's "VERY hard to override". See Database connection parameters are tied to the filesystem · Issue #5297 · rails/rails · GitHub

I've been using variations of that for a long time, and it works pretty well.

Cheers, -foca

2

3.2+ should have support for a DATABASE_URL environment variable:

  https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_handling.rb#L39

Which you should be able to use like this:

  $ DATABASE_URL='sqlite3:///db/development.sqlite3' rake do:whatever

But that doesn't help the problem in #5297. The problem in #5297 is that Heroku calculates it's own parameters to pass in for the URL. AFAIK, there is no way to augment the connection parameters that Heroku sends. But this seems like an issue with Heroku rather than Rails.

If you find entry points where the environment variable *isn't* used, then we should consider it a bug. For example, I just discovered that `rake db:schema:dump` will not use the environment variable:

  https://github.com/rails/rails/blob/master/activerecord/lib/active_record/railties/databases.rake#L229

So someone should send a patch for that. :slight_smile:

3

If you find entry points where the environment variable *isn't* used, then we should consider it a bug. For example, I just discovered that `rake db:schema:dump` will not use the environment variable:   https://github.com/rails/rails/blob/master/activerecord/lib/active_record/railties/databases.rake#L229

So someone should send a patch for that. :slight_smile:

Is it simple as:

- ActiveRecord::Base.establish_connection(Rails.env) + ActiveRecord::Base.establish_connection(ENV["DATABASE_URL"]

Rails.env)

wherever I see it not being used? Also inside namespace :test? Are there tests for rake tasks?

4

Yes, but I think it would be better if we change the definition of `establish_connection` in connection_handling.rb. Like this:

diff --git a/activerecord/lib/active_record/connection_handling.rb b/activerecord/lib/active_record/connection_handling.rb index bda41df..ce1f84f 100644 --- a/activerecord/lib/active_record/connection_handling.rb +++ b/activerecord/lib/active_record/connection_handling.rb @@ -36,7 +36,7 @@ module ActiveRecord