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Diffstat (limited to 'lib/mixlib/config.rb')
| -rw-r--r-- | lib/mixlib/config.rb | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/lib/mixlib/config.rb b/lib/mixlib/config.rb new file mode 100644 index 0000000..bfa488c --- /dev/null +++ b/lib/mixlib/config.rb @@ -0,0 +1,118 @@ +# +# Author:: Adam Jacob (<adam@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 + + @@configuration = Hash.new + + # 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) + if File.exists?(filename) && File.readable?(filename) + self.instance_eval(IO.read(filename), filename, 1) + else + raise IOError, "Cannot open or read #{filename}!" + end + end + + # Pass Mixlib::Config.configure() a block, and it will yield @configuration. + # + # === Parameters + # <block>:: A block that takes @configure as it's argument + def configure(&block) + block.call(@@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) + if @@configuration.has_key?(config_option.to_sym) + @@configuration[config_option.to_sym] + else + raise ArgumentError, "Cannot find configuration option #{config_option.to_s}" + end + 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) + @@configuration[config_option.to_sym] = 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) + @@configuration.has_key?(key.to_sym) + 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 + + # If we have the symbol, or if we need to set it + if @@configuration.has_key?(method_symbol) || num_args > 0 + if num_args > 0 + @@configuration[method_symbol] = num_args == 1 ? args[0] : args + end + return @@configuration[method_symbol] + else + # Otherwise, we're just looking it up + raise ArgumentError, "Cannot find configuration option #{method_symbol.to_s}" + end + end + + end +end |