Add Rails::Application#config_for

[rafaelfranca]

This is a convenience for loading configuration for the current Rails
environment.

production:
  url: http://127.0.0.1:8080
  namespace: bc3_production
development:
  url: http://bc3.dev/cleversafe
  namespace: bc3_development

Cleversafe.config = Application.config_for :cleversafe

cc @dhh

[dhh]

Might use a better example, like:

# config/production.rb
BCX::Application.configure do
  config.middleware.use ExceptionNotifier, config_for(:exception_notification)
end

Otherwise looks good!

[matthewd]

Might be clearer to read if this was called something else? As it is, the test later uses 'custom' in two places to refer to different things...

[egilburg]

If Rails will provide canonical way to manage env-specific configuration from yaml, should it be in scope to have inheritable application yaml configuration, overridable per environment, similar to how the ruby config in environment.rb/application.rb is inherited and overridable by environments/foo.rb?

[rafaelfranca]

@egilburg not sure if I follow. Is not YAML inheritance sufficient?

development: &default
  foo:
  bar:

production:
  <<*default
  bar:

[dhh]

I haven’t found that helpful or useful for my usage of this feature. These config files are usually pretty small, and it gives more clarity to have the env declarations together.

On Jul 10, 2014, at 3:59 PM, Eugene Gilburg notifications@github.com wrote:

If Rails will provide canonical way to manage env-specific configuration from yaml, should it be in scope to have inheritable application yaml configuration, overridable per environment, similar to how the ruby config in environment.rb is inherited and overridable by environments/foo.rb?

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[egilburg]

@rafaelfranca, sure, but this is a bit of sugar to match the sugar we get from the Ruby config. So instead of:

  default: &default
    foo: 'bar'
  production:
    << &default
    baz: 'production_baz'

We'd have:

  application:
    foo: 'bar'
  production:
    baz: 'production_baz'

It only saves a few lines, but the idea that it follows the pattern Rails uses where environment/production.rb inherits everything in application.rb, helping to group concerns together.

[rafaelfranca]

I really believe we should not try to include new features on yaml parsing 😄

[dhh]

Ah, Eugene, I see what you mean. I thought you wanted separate files per env.

I’m with Rafael, though. YAML is hairy enough as it is. I don’t think we want to add to that.

On Jul 10, 2014, at 4:04 PM, Eugene Gilburg notifications@github.com wrote:

@rafaelfranca, sure, but this is a bit of sugar to match the sugar we get from the Ruby config. So instead of:

default:

foo: 'bar'

production:

<< &default

baz: 'production_baz'
We'd have:

application:

foo: 'bar'

production:

baz: 'production_baz'
It only saves a few lines, but the idea that it follows the pattern Rails uses where environment/production.rb inherits everything in application.rb, helping to group concerns together.

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[guilleiguaran]

+1 to @dhh @rafaelfranca please keep yaml parsing as is 😅

[egilburg]

This wouldn't be so much parsing as merging the already parsed values:

  data = YAML.load(ERB.new(yaml.read).result) || {}
  data['application'] || {}).merge(data[Rails.env] || {}).presence

If it's not considered useful from behavior perspective, sure. Just pointing out we don't need to change any of the actual Yaml parsing itself.

[egilburg]

Also, if yaml has no env key defined, it seems current implementation returns nil. Should it return empty hash instead to behave more like a null object? Otherwise users must remember to always define all environment keys even if they only need config for some environments.

[rafaelfranca]

This would lead some questions like: Why database.yml doesn't work this way? Why it doesn't work when I don't use config_for? Why it only work inside Rails?

I think we should stick with what yaml give to us.

About the nil return my first implementation was returning {}, so I'm fine to changing it to always return a Hash.

[robin850]

Nitpicking but the comma's place is wrong.

[robin850]

Nice patch! 👍 Maybe we can also simplify Rails::Application#secrets definition with this feature, no ?

[rafaelfranca]

I can't simplify secrets because the behaviour when the secrets.yml files doesn't exist is different from when a generic config file doesn't exist. To use config_for in secrets I'd had to raise an specific exception when the file doesn't exist and catching on secrets. I believe it is not worth to remove this duplication.

[mdeering]

Any reason behind raising the default RuntimeError VS something more specific such as IOError or reraising the Errno::ENOENT?

[dhh]

Nope, fine to raise re-raise, as long as we use that new message.

On Feb 16, 2015, at 10:35, Michael Deering notifications@github.com wrote:

In railties/lib/rails/application.rb:

• url: http://localhost:3001

• namespace: my_app_development

• # config/production.rb

• MyApp::Application.configure do

• config.middleware.use ExceptionNotifier, config_for(:exception_notification)

• end

• def config_for(name)

•  yaml = Pathname.new("#{paths["config"].existent.first}/#{name}.yml")
  

•  if yaml.exist?
  

•    require "yaml"
  

•    require "erb"
  

•    (YAML.load(ERB.new(yaml.read).result) || {})[Rails.env] || {}
  

•  else
  

•    raise "Could not load configuration. No such file - #{yaml}"
  

Any reason behind raising the default RuntimeError VS something more specific such as IOError or reraising the Errno::ENOENT?

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