module Mixlib::Config

Constants

NOT_PASSED
VERSION

Public Class Methods

extended(base) click to toggle source
# File lib/mixlib/config.rb, line 29
def self.extended(base)
  class << base; attr_accessor :configuration; end
  class << base; attr_accessor :configurables; end
  class << base; attr_accessor :config_contexts; end
  class << base; attr_accessor :config_parent; end
  base.configuration = Hash.new
  base.configurables = Hash.new
  base.config_contexts = Hash.new
  base.initialize_mixlib_config
end

Public Instance Methods

[](config_option) click to toggle source

Get the value of a config option

Parameters

config_option<Symbol>

The config option to return

Returns

value

The value of the config option

Raises

<UnknownConfigOptionError>

If the config option does not exist and strict mode is on.

# File lib/mixlib/config.rb, line 73
def [](config_option)
  internal_get(config_option.to_sym)
end
[]=(config_option, value) click to toggle source

Set the value of a config option

Parameters

config_option<Symbol>

The config option to set (within the [])

value

The value for the config option

Returns

value

The new value of the config option

Raises

<UnknownConfigOptionError>

If the config option does not exist and strict mode is on.

# File lib/mixlib/config.rb, line 88
def []=(config_option, value)
  internal_set(config_option.to_sym, value)
end
config_attr_writer(method_symbol, &block) click to toggle source

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

# File lib/mixlib/config.rb, line 245
def config_attr_writer(method_symbol, &block)
  configurable(method_symbol).writes_value(&block)
end
config_context(symbol, &block) click to toggle source

Allows you to create a new config context where you can define new options with default values.

This method allows you to open up the configurable more than once.

For example:

config_context :server_info do

configurable(:url).defaults_to("http://localhost")

end

Parameters

symbol<Symbol>: the name of the context block<Block>: a block that will be run in the context of this new config class.

# File lib/mixlib/config.rb, line 313
def config_context(symbol, &block)
  if configurables.has_key?(symbol)
    raise ReopenedConfigurableWithConfigContextError, "Cannot redefine config value #{symbol} with a config context"
  end

  if config_contexts.has_key?(symbol)
    context = config_contexts[symbol]
  else
    context = Class.new
    context.extend(::Mixlib::Config)
    context.config_parent = self
    config_contexts[symbol] = context
    define_attr_accessor_methods(symbol)
  end

  if block
    context.instance_eval(&block)
  end

  context
end
config_strict_mode(value = NOT_PASSED) click to toggle source

Gets or sets strict mode. When strict mode is on, only values which were specified with configurable(), default() or writes_with() may be retrieved or set. Getting or setting anything else will cause Mixlib::Config::UnknownConfigOptionError to be thrown.

If this is set to :warn, unknown values may be get or set, but a warning will be printed with Chef::Log.warn if this occurs.

Parameters

value<String>

pass this value to set strict mode [optional]

Returns

Current value of config_strict_mode

Raises

<ArgumentError>

if value is set to something other than true, false, or :warn

# File lib/mixlib/config.rb, line 354
def config_strict_mode(value = NOT_PASSED)
  if value == NOT_PASSED
    if @config_strict_mode.nil?
      if config_parent
        config_parent.config_strict_mode
      else
        false
      end
    else
      @config_strict_mode
    end
  else
    self.config_strict_mode = value
  end
end
config_strict_mode=(value) click to toggle source

Sets strict mode. When strict mode is on, only values which were specified with configurable(), default() or writes_with() may be retrieved or set. All other values

If this is set to :warn, unknown values may be get or set, but a warning will be printed with Chef::Log.warn if this occurs.

Parameters

value<String>

pass this value to set strict mode [optional]

Raises

<ArgumentError>

if value is set to something other than true, false, or :warn

# File lib/mixlib/config.rb, line 383
def config_strict_mode=(value)
  if ![ true, false, :warn, nil ].include?(value)
    raise ArgumentError, "config_strict_mode must be true, false, nil or :warn"
  end
  @config_strict_mode = value
end
configurable(symbol) { |configurables| ... } click to toggle source

metaprogramming to set information about a config option. This may be used in one of two ways:

  1. Block-based:

configurable(:attr) do

defaults_to 4
writes_value { |value| 10 }

end

  1. Chain-based:

configurable(:attr).defaults_to(4).writes_value { |value| 10 }

Currently supported configuration:

defaults_to(value): value returned when configurable has no explicit value defaults_to BLOCK: block is run when the configurable has no explicit value writes_value BLOCK: block that is run to filter a value when it is being set

Parameters

symbol<Symbol>

Name of the config option

default_value<Object>

Default value [optional]

block<Block>

Logic block that calculates default value [optional]

Returns

The value of the config option.

# File lib/mixlib/config.rb, line 284
def configurable(symbol, &block)
  unless configurables[symbol]
    if config_contexts.has_key?(symbol)
      raise ReopenedConfigContextWithConfigurableError, "Cannot redefine config_context #{symbol} as a configurable value"
    end
    configurables[symbol] = Configurable.new(symbol)
    define_attr_accessor_methods(symbol)
  end
  if block
    yield(configurables[symbol])
  end
  configurables[symbol]
end
configure() { |configuration| ... } click to toggle source

Pass Mixlib::Config.configure() a block, and it will yield itself

Parameters

block<Block>

A block that is called with self.configuration as the argument.

# File lib/mixlib/config.rb, line 59
def configure(&block)
  yield(self.configuration)
end
default(symbol, default_value = nil, &block) click to toggle source

metaprogramming to set the default value for the given config option

Parameters

symbol<Symbol>

Name of the config option

default_value<Object>

Default value (can be unspecified)

block<Block>

Logic block that calculates default value

# File lib/mixlib/config.rb, line 255
def default(symbol, default_value = nil, &block)
  configurable(symbol).defaults_to(default_value, &block)
end
delete(symbol) click to toggle source

Resets a config option to its default.

Parameters

symbol<Symbol>

Name of the config option

# File lib/mixlib/config.rb, line 108
def delete(symbol)
  self.configuration.delete(symbol)
end
from_file(filename) click to toggle source

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

filename<String>

A filename to read from

# File lib/mixlib/config.rb, line 51
def from_file(filename)
  self.instance_eval(IO.read(filename), filename, 1)
end
has_key?(key) click to toggle source

Check if Mixlib::Config has a config option.

Parameters

key<Symbol>

The config option to check for

Returns

<True>

If the config option exists

<False>

If the config option does not exist

# File lib/mixlib/config.rb, line 100
def has_key?(key)
  self.configuration.has_key?(key.to_sym)
end
hash_dup() click to toggle source

Creates a shallow copy of the internal hash NOTE: remove this in 3.0 in favor of save. This is completely useless with default values and configuration_context.

Returns

result of Hash#dup

# File lib/mixlib/config.rb, line 233
def hash_dup
  save
end
initialize_mixlib_config() click to toggle source
# File lib/mixlib/config.rb, line 40
def initialize_mixlib_config
  @config_strict_mode = nil
end
keys() click to toggle source

Return the set of config hash keys. This only returns hash keys which have been set by the user. In future versions this will likely be removed in favor of something more explicit. For now though, we want this to match has_key?

Returns

result of Hash#keys

# File lib/mixlib/config.rb, line 223
def keys
  self.configuration.keys
end
merge!(hash) click to toggle source

Merge an incoming hash with our config options

Parameters

hash<Hash>: a hash in the same format as output by save.

Returns

self

# File lib/mixlib/config.rb, line 204
def merge!(hash)
  hash.each do |key, value|
    if self.config_contexts.has_key?(key)
      # Grab the config context and let internal_get cache it if so desired
      self.config_contexts[key].restore(value)
    else
      self.configuration[key] = value
    end
  end
  self
end
method_missing(method_symbol, *args) click to toggle source

Allows for simple lookups and setting of config options via method calls on Mixlib::Config. If there any arguments to the method, they are used to set the value of the config option. Otherwise, it’s a simple get operation.

Parameters

method_symbol<Symbol>

The method called. Must match a config option.

*args

Any arguments passed to the method

Returns

value

The value of the config option.

Raises

<UnknownConfigOptionError>

If the config option does not exist and strict mode is on.

# File lib/mixlib/config.rb, line 403
def method_missing(method_symbol, *args)
  method_symbol = $1.to_sym if method_symbol.to_s =~ /(.+)=$/
  internal_get_or_set(method_symbol, *args)
end
reset() click to toggle source

Resets all config options to their defaults.

# File lib/mixlib/config.rb, line 113
def reset
  self.configuration = Hash.new
  self.config_contexts.values.each { |config_context| config_context.reset }
end
restore(hash) click to toggle source

Restore non-default values from the given hash.

Parameters

hash<Hash>: a hash in the same format as output by save.

Returns

self

# File lib/mixlib/config.rb, line 186
def restore(hash)
  self.configuration = hash.reject { |key, value| config_contexts.has_key?(key) }
  config_contexts.each do |key, config_context|
    if hash.has_key?(key)
      config_context.restore(hash[key])
    else
      config_context.reset
    end
  end
end
save(include_defaults = false) click to toggle source

Makes a copy of any non-default values.

This returns a shallow copy of the hash; while the hash itself is duplicated a la dup, modifying data inside arrays and hashes may modify the original Config object.

Returns

Hash of values the user has set.

Examples

For example, this config class:

class MyConfig < Mixlib::Config
  default :will_be_set, 1
  default :will_be_set_to_default, 1
  default :will_not_be_set, 1
  configurable(:computed_value) { |x| x*2 }
  config_context :group do
    default :will_not_be_set, 1
  end
  config_context :group_never_set
end

MyConfig.x = 2
MyConfig.will_be_set = 2
MyConfig.will_be_set_to_default = 1
MyConfig.computed_value = 2
MyConfig.group.x = 3

produces this:

MyConfig.save == {
  :x => 2,
  :will_be_set => 2,
  :will_be_set_to_default => 1,
  :computed_value => 4,
  :group => {
    :x => 3
  }
}
# File lib/mixlib/config.rb, line 161
def save(include_defaults = false)
  result = self.configuration.dup
  if include_defaults
    (self.configurables.keys - result.keys).each do |missing_default|
      # Ask any configurables to save themselves into the result array
      if self.configurables[missing_default].has_default
        result[missing_default] = self.configurables[missing_default].default
      end
    end
  end
  self.config_contexts.each_pair do |key, context|
    context_result = context.save(include_defaults)
    result[key] = context_result if context_result.size != 0 || include_defaults
  end
  result
end
Also aliased as: to_hash
to_hash(include_defaults = false)
Alias for: save

Private Instance Methods

define_attr_accessor_methods(symbol) click to toggle source
# File lib/mixlib/config.rb, line 457
def define_attr_accessor_methods(symbol)
  # When Ruby 1.8.7 is no longer supported, this stuff can be done with define_singleton_method!
  meta = class << self; self; end
  # Setter
  meta.send :define_method, "#{symbol}=".to_sym do |value|
    internal_set(symbol, value)
  end
  # Getter
  meta.send :define_method, symbol do |*args, &block|
    # If a block was given, eval it in the context
    if block
      # If the block expects no arguments, then instance_eval
      if block.arity == 0
        internal_get(symbol).instance_eval(&block)
      else # yield to the block
        block.yield(internal_get(symbol))
      end
    else
      internal_get_or_set(symbol, *args)
    end
  end
end
internal_get(symbol) click to toggle source
# File lib/mixlib/config.rb, line 431
def internal_get(symbol)
  if configurables.has_key?(symbol)
    configurables[symbol].get(self.configuration)
  elsif config_contexts.has_key?(symbol)
    config_contexts[symbol]
  else
    if config_strict_mode == :warn
      Chef::Log.warn("Reading unsupported config value #{symbol}.")
    elsif config_strict_mode
      raise UnknownConfigOptionError, "Reading unsupported config value #{symbol}."
    end
    configuration[symbol]
  end
end
internal_get_or_set(symbol, *args) click to toggle source
# File lib/mixlib/config.rb, line 446
def internal_get_or_set(symbol, *args)
  num_args = args.length
  # Setting
  if num_args > 0
    internal_set(symbol, num_args == 1 ? args[0] : args)
  end

  # Returning
  internal_get(symbol)
end
internal_set(symbol, value) click to toggle source

Internal dispatch setter for config values.

Parameters

symbol<Symbol>

Name of the method (variable setter)

value<Object>

Value to be set in config hash

# File lib/mixlib/config.rb, line 416
def internal_set(symbol, value)
  if configurables.has_key?(symbol)
    configurables[symbol].set(self.configuration, value)
  elsif config_contexts.has_key?(symbol)
    config_contexts[symbol].restore(value.to_hash)
  else
    if config_strict_mode == :warn
      Chef::Log.warn("Setting unsupported config value #{symbol}.")
    elsif config_strict_mode
      raise UnknownConfigOptionError, "Cannot set unsupported config value #{symbol}."
    end
    configuration[symbol] = value
  end
end