Ruby Configuration: replacing nested key value for dev environment doesn't work

Question

Case: Development environment log level is DEBUG while Production is INFO. I want to use every default log configuration and overwrite only level if environment == develoment.

Problem: first level configs can be over-written but not sub levels.

Consider Example Code:

#file: config.rb

default = Configuration.for('default'){
  log {
    file '/tmp/foo.log'
    level 'WARN'
    freq 'daily'
  }
}

development = Configuration.for( 'development', default) {
  log {
    level 'DEBUG'
  }
}

In main file, I use the above code like so

# main.rb

require 'config.rb'    
$CONFIG = Configuration.for $DEV_ENV # either ('default' || 'development')
p $CONFIG.log.freq

I get an method missing error:

`undefined method `freq' for #<Configuration:0x00000003a65d80> (NoMethodError)`

The only (ugly) solution i have is to point file and freq values back to default like so:

  log {
    file default.log.file
    level 'DEBUG'
    freq default.log.freq
  }

EEWWW!! Nasty!

Any other suggestions? I've tried to implement something like this with SettingsLogic and Configatron too at no avail. There goes the three top configuration gems for Ruby. Do I need to make my own?? Is this really such an exotic example?

Would love your feedback or suggestions.

Answer 1

I was able to solve your problem with SettingsLogic and anchor labels in YAML.

My config file:

defaults: &defaults
  log: &logdefault
      file:  /tmp/foo.log
      level: WARN
      freq: daily

development:
  <<: *defaults
  log:
      <<: *logdefault
      level: DEBUG

test:
  <<: *defaults

production:
  <<: *defaults

The trick is to store the defaults in an anchor label and re-use it, when you try to redefine a part of it. You need an anchor for each level.

You can use it as

require 'settingslogic'  #https://github.com/settingslogic/settingslogic
class SettingsDEV < Settingslogic
  source "./application.yml"
  namespace 'development'
end
p SettingsDEV.log #{"file"=>"/tmp/foo.log", "level"=>"DEBUG", "freq"=>"daily"}

class SettingsProd < Settingslogic
  source "./application.yml"
  namespace 'production'
end
p SettingsProd.log  #{"file"=>"/tmp/foo.log", "level"=>"WARN", "freq"=>"daily"}