fun_with_configurations : Your objects must be configurized!

Configuration and settings are the beating heart and dark, twisted soul of your operation.

Let’s look at some example code:

class Computer; end;

Computer.install_fwc_config do
  servers do
    hopeful_host do
      ip "192.168.0.25"
      services :mysql, :memcached, :email, :backup
      uptime `uptime`.strip
      config_script "/var/configurations/hopeful.conf"
    end

    squishy_host do
      ip "192.168.0.27"
      services :postresql, :couchdb
      uptime `uptime`.strip
      config_script "/var/configurations/squishy.conf"
    end
  end

  workstations do
    betty do
      ip "192.168.0.14"
      os "Ubuntu Linux 13.04"
    end

    veronica do
      ip "192.168.0.15"
      os "Solaris 10"
    end
  end
end

Computers.config.servers.hopeful_host.ip  # "192.168.0.25"
Computers.config.workstations.betty.ip    # "192.168.0.14"
Computers.config.try.servers.grumpy_host.ip.success?    # false  (doesn't have that configuration setting)

You can also load from a hash:

@obj.install_fwc_config_from_hash({
  servers: {
    hopeful_host: {
      ip: "192.168.0.25",
      services :mysql, :memcached, :email, :backup   # stores args as an array

      ...  (and so on)
    }
  }
})

@obj.config.servers.hopeful_host.services    # [:mysql, :memcached, :email, :backup]

Or from a yaml string:

@obj.install_fwc_config_from_file( "~/data/configs/circumstantial.yml" )   # looks for .yml or .yaml as the file extension

The file should represent hashes of hashes. Anything not a hash will be treated as a leaf setting (arrays, etc.).

Last and best, you can load a pure Ruby configuration:

@obj.install_fwc_config_from_file( "~/data/configs/rubicon.rb" )

Contents of rubicon.rb would be similar to what appears in the install_fwc_config block:

server do
  thor do
    ip "212.36.64.10"
    role "mysql"
  end

  loki do
    ip "212.36.64.11"
    role "web"
  end

  odin do
    ip "212.36.64.12"
    role "bitcoin_mining"
  end

  fenrir do
    ip "212.36.64.13"
    role "igniting_ragnarok"
  end
end

Other features

There are a couple of affordances for assigning variables to an object from a config. The first is fwc_assign!(), which takes an object and assigns its instance_vars. More code!

require "fun_with_configurations"
class Person
  attr_accessor :ssn, :birthdate, :password
end

p = Person.new
p.install_fwc_config do
  age 51

  data do
    personal do
      ssn "555-555-5555"
      birthdate "2001-03-01"
      password  "mice"
    end
  end
end

p.config.data.personal.fwc_assign!

p.ssn   # => "555-555-5555"
p.birthdate   # => "2001-03-01"
(and so on)

By default, fwc_assign!() assigns the instance variables of the config’s object (the object you call object.config on). But you can also pass fwc_assign a different object to config instead.

class Computer; end

Computer.install_fwc_config_from_file( file )

betty = Computer.config.betty.fwc_assign!( Computer.new )
veronica = Computer.config.veronica.fwc_assign!( Computer.new )
odin = Computer.config.odin.fwc_assign!( Computer.new )

computers = {}

# Alternately
Computer.config.fwc do |c|    # You'll meet .fwc() soon
  c.each do |k, config|
    computers[k] = config.fwc_assign!( Computer.new )
  end
end

odin.ip # "192.168.0.15"

Another convenience method lets

MyRails.config.constant_contact.fwc do |config|
  @key      = config.oauth.key
  @secret   = config.oauth.secret
  @redir    = config.oauth.redirect_url
  @user     = config.user
  @password = config.password
end

Basically, this is meant to spare you from typing the longhand form:

@key      = MyRails.config.constant_contact.oauth.key
@secret   = MyRails.config.constant_contact.oauth.secret
@redir    = MyRails.config.constant_contact.oauth.redirect_url
@user     = MyRails.config.constant_contact.user
@password = MyRails.config.constant_contact.password

FunWith::Patterns::Loader integration

To use configurations with the Loader pattern:

require 'fun_with_configurations'
require 'fun_with_patterns'

class Computer
  attr_accessor :label

  # Look up individual configurations via Computer[:bob_system]
  loader_pattern_configure( :bracketwise_lookup,
                            :warn_on_key_change,  # Warn if an existing lookup key is overwritten
                            { :key   => :label,     # Key is found by calling method label()
                              :style => FunWith::Configurations::LoadingStyle } ) # Interprets the file as a FWC::Config
end

Computer.loader_pattern_load_from_dir( "~/.config/computers" )  # loads all the configurations in the directory
puts Computer[:bob_system].memory  # ==> "4GB"

Internally, the LoadingStyle simply offloads the loading work to Config.from_file(), so any valid configuration format will do (.rb, .yaml).

Contributing to fun_with_configurations

Boilerplate from Jeweler. Seems reasonable.

Check out the latest master to make sure the feature hasn’t been implemented or the bug hasn’t been fixed yet.
Check out the issue tracker to make sure someone already hasn’t requested it and/or contributed it.
Fork the project.
Start a feature/bugfix branch.
Commit and push until you are happy with your contribution.
Make sure to add tests for it. This is important so I don’t break it in a future version unintentionally.
Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.

fun_with_configurations : Your objects must be configurized!

Other features

FunWith::Patterns::Loader integration

Contributing to fun_with_configurations

Copyright