configuration.rb¶ ↑

pure ruby scoped configuration files (Forked version)

Description¶ ↑

configuration.rb provides a mechanism for configuring ruby programs with ruby configuration files. a configuration.rb file, for example ‘config/app.rb’, can be written simply as

Configuration.for('app') {
  key 'value'
  foo 'bar'
  port 42
}

and loaded via the normal ruby require/load mechanism

Kernel.load 'config/app.rb'

or with a slightly augmented loading mechnanism which simply searches an extra set of paths in addition to the standard ones

Configuration.path = %w( config configuration )

Configuration.load 'app'

configurations are completely open

Configuration.for('app') {
  object_id 'very open'
}

support arbitrarily nested values

Configuration.for('app') {
  a { b { c { d 42 } } }
}

c = Configuration.for 'app'

p c.a.b.c.d #=> 42

allow POLS scoped lookup of vars

Configuration.for('config') {
  outer 'bar'

  inner {
    value 42
  }
}

c = Configuration.for 'config'

p c.outer       #=> 'bar'
p c.inner.value #=> 42
p c.inner.outer #=> 'bar'

allow default values

default = Configuration.for( 'default' ) {
  a 1
  b 2
}

c = Configuration.for( 'config', default ) {
 a 10
}

p c.a     #=> 10
p c.b     #=> 2

and not a whole lot else - configuration.rb is s very small library consisting of one file and < 150 loc

Samples¶ ↑

samples/a.rb¶ ↑

~ > cat samples/a.rb

  #
  # basic usage is quite, simple, load the config and use it's values.  the
  # config syntax is fairly obvious, i think, but note that it *is* ruby and any
  # ruby can be included.  also note that each config is named, allowing
  # multiple configs to be places in one file
  #
    require 'configuration'

    c = Configuration.load 'a'

    p c.a + c.b - c.c

~ > ruby samples/a.rb

  42

samples/b.rb¶ ↑

~ > cat samples/b.rb

  #
  # configuration.rb supports a very natural nesting syntax.  note how values
  # are scoped in a POLS fashion
  #
    require 'configuration'

    c = Configuration.for 'b'

    p c.www.url
    p c.db.url
    p c.mail.url

~ > ruby samples/b.rb

  "http://codeforpeople.com:80"
  "db://codeforpeople.com:5342"
  "mail://gmail.com:25"

samples/c.rb¶ ↑

~ > cat samples/c.rb

  #
  # configuration.rb let's you keep code very dry.
  #

    require 'configuration'

    Configuration.load 'c'

    p Configuration.for('development').db
    p Configuration.for('production').db
    p Configuration.for('testing').db

~ > ruby samples/c.rb

  "db/development"
  "db/production"
  "db/testing"

samples/d.rb¶ ↑

~ > cat samples/d.rb

  #
  # configuration.rb makes use of an external blank slate dsl, this means that
  # you Configuration objects do, in fact, have all built-in ruby methods such
  # as #inspect, etc, *unless* you configure over the top of them.  the effect
  # is a configuration object that behaves like a nice ruby object, but which
  # allows *any* key to be configured
  #
    require 'configuration'

    c = Configuration.for 'd'

    p c.object_id
    p c.inspect
    p c.p

~ > ruby samples/d.rb

  config/d.rb:2:in `object_id': wrong number of arguments (1 for 0) (ArgumentError)
    from config/d.rb:2
    from ./lib/configuration.rb:159:in `instance_eval'
    from ./lib/configuration.rb:159:in `call'
    from ./lib/configuration.rb:159:in `method_missing'
    from ./lib/configuration.rb:105:in `evaluate'
    from ./lib/configuration.rb:68:in `initialize'
    from ./lib/configuration.rb:29:in `new'
    from ./lib/configuration.rb:29:in `for'
    from config/d.rb:1
    from ./lib/configuration.rb:53:in `load'
    from ./lib/configuration.rb:53:in `load'
    from ./lib/configuration.rb:31:in `for'
    from samples/d.rb:10

samples/e.rb¶ ↑

~ > cat samples/e.rb

  #
  # configuration.rb uses a totally clean slate dsl for the block.  if you need
  # to access base Object methods you can do this
  #

    require 'configuration'

    c = Configuration.for 'e'

    p c.foo
    p c.bar
    p c.foobar

~ > ruby samples/e.rb

  42
  "forty-two"
  42.0

samples/f.rb¶ ↑

~ > cat samples/f.rb

  #
  # configuration.rb let's you inherit values from another configuration.
  # Like this, you keep your code very dry.
  #

    require 'configuration'

    Configuration.load 'f'

    p c.a
    p c.b

~ > ruby samples/f.rb

  10
  2

Author¶ ↑

[email protected]

Forked to allow for upgrade to Ruby 1.9.3¶ ↑

in ruby 1.9.3 methods(false) returns an array of symbols in ruby 1.8.7 methods(false) returns an array of strings

the Configuration class supports an each method based on methods(false) Galaxy passes this output to the Sequel Gem Sequel treats symbols very differently from strings, symbols tend to be columns names, strings are values this fork will continue to make the output of Configuration#each an array of strings for compatibility with Sequel