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#
# Author:: Adam Jacob (<adam@opscode.com>)
# Author:: Nuo Yan (<nuo@opscode.com>)
# Author:: Christopher Brown (<cb@opscode.com>)
# Copyright:: Copyright (c) 2008 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
module Mixlib
module Config
def self.extended(base)
class << base; attr_accessor :configuration; end
base.configuration = Hash.new
end
# Loads a given ruby file, and runs instance_eval against it in the context of the current
# object.
#
# Raises an IOError if the file cannot be found, or is not readable.
#
# === Parameters
# <string>:: A filename to read from
def from_file(filename)
self.instance_eval(IO.read(filename), filename, 1)
end
# Pass Mixlib::Config.configure() a block, and it will yield self.configuration.
#
# === Parameters
# <block>:: A block that is sent self.configuration as its argument
def configure(&block)
block.call(self.configuration)
end
# Get the value of a configuration option
#
# === Parameters
# config_option<Symbol>:: The configuration option to return
#
# === Returns
# value:: The value of the configuration option
#
# === Raises
# <ArgumentError>:: If the configuration option does not exist
def [](config_option)
self.configuration[config_option.to_sym]
end
# Set the value of a configuration option
#
# === Parameters
# config_option<Symbol>:: The configuration option to set (within the [])
# value:: The value for the configuration option
#
# === Returns
# value:: The new value of the configuration option
def []=(config_option, value)
internal_set(config_option,value)
end
# Check if Mixlib::Config has a configuration option.
#
# === Parameters
# key<Symbol>:: The configuration option to check for
#
# === Returns
# <True>:: If the configuration option exists
# <False>:: If the configuration option does not exist
def has_key?(key)
self.configuration.has_key?(key.to_sym)
end
# Merge an incoming hash with our config options
#
# === Parameters
# hash<Hash>:: The incoming hash
#
# === Returns
# result of Hash#merge!
def merge!(hash)
self.configuration.merge!(hash)
end
# Return the set of config hash keys
#
# === Returns
# result of Hash#keys
def keys
self.configuration.keys
end
# Creates a shallow copy of the internal hash
#
# === Returns
# result of Hash#dup
def hash_dup
self.configuration.dup
end
# Internal dispatch setter, calling either the real defined method or setting the
# hash value directly
#
# === Parameters
# method_symbol<Symbol>:: Name of the method (variable setter)
# value<Object>:: Value to be set in config hash
#
def internal_set(method_symbol,value)
method_name = method_symbol.id2name
if self.respond_to?("#{method_name}=".to_sym)
self.send("#{method_name}=", value)
else
self.configuration[method_symbol] = value
end
end
protected :internal_set
# metaprogramming to ensure that the slot for method_symbol
# gets set to value after any other logic is run
# === Parameters
# method_symbol<Symbol>:: Name of the method (variable setter)
# blk<Block>:: logic block to run in setting slot method_symbol to value
# value<Object>:: Value to be set in config hash
#
def config_attr_writer(method_symbol, &blk)
meta = class << self; self; end
method_name = "#{method_symbol.to_s}=".to_sym
meta.send :define_method, method_name do |value|
self.configuration[method_symbol] = blk.call(value)
end
end
# Allows for simple lookups and setting of configuration options via method calls
# on Mixlib::Config. If there any arguments to the method, they are used to set
# the value of the configuration option. Otherwise, it's a simple get operation.
#
# === Parameters
# method_symbol<Symbol>:: The method called. Must match a configuration option.
# *args:: Any arguments passed to the method
#
# === Returns
# value:: The value of the configuration option.
#
# === Raises
# <ArgumentError>:: If the method_symbol does not match a configuration option.
def method_missing(method_symbol, *args)
num_args = args.length
# Setting
if num_args > 0
method_symbol = $1.to_sym unless (method_symbol.to_s =~ /(.+)=$/).nil?
internal_set method_symbol, (num_args == 1 ? args[0] : args)
end
# Returning
self.configuration[method_symbol]
end
end
end
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