Module: Mixlib::Config

Defined in:
lib/mixlib/config.rb,
lib/mixlib/config/version.rb,
lib/mixlib/config/configurable.rb,
lib/mixlib/config/unknown_config_option_error.rb,
lib/mixlib/config/reopened_config_context_with_configurable_error.rb,
lib/mixlib/config/reopened_configurable_with_config_context_error.rb

Defined Under Namespace

Classes: Configurable, ReopenedConfigContextWithConfigurableError, ReopenedConfigurableWithConfigContextError, UnknownConfigOptionError

Constant Summary collapse

NOT_PASSED = 
Object.new
VERSION = 
"2.2.1"

Class Method Summary collapse

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_symbol, *args) ⇒ Object

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.



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# File 'lib/mixlib/config.rb', line 393

def method_missing(method_symbol, *args)
  method_symbol = $1.to_sym if method_symbol.to_s =~ /(.+)=$/
  internal_get_or_set(method_symbol, *args)
end

Class Method Details

.extended(base) ⇒ Object 



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# 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
end

Instance Method Details

#[](config_option) ⇒ Object

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.



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# File 'lib/mixlib/config.rb', line 68

def [](config_option)
  internal_get(config_option.to_sym)
end

#[]=(config_option, value) ⇒ Object

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.



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# File 'lib/mixlib/config.rb', line 83

def []=(config_option, value)
  internal_set(config_option.to_sym, value)
end

#config_attr_writer(method_symbol, &block) ⇒ Object

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



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# File 'lib/mixlib/config.rb', line 235

def config_attr_writer(method_symbol, &block)
  configurable(method_symbol).writes_value(&block)
end

#config_context(symbol, &block) ⇒ Object

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.



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# File 'lib/mixlib/config.rb', line 303

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) ⇒ Object

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



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# File 'lib/mixlib/config.rb', line 344

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) ⇒ Object

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



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# File 'lib/mixlib/config.rb', line 373

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, &block) ⇒ Object

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.



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# File 'lib/mixlib/config.rb', line 274

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
    block.call(configurables[symbol])
  end
  configurables[symbol]
end

#configure(&block) ⇒ Object

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.



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# File 'lib/mixlib/config.rb', line 54

def configure(&block)
  block.call(self.configuration)
end

#default(symbol, default_value = nil, &block) ⇒ Object

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



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# File 'lib/mixlib/config.rb', line 245

def default(symbol, default_value = nil, &block)
  configurable(symbol).defaults_to(default_value, &block)
end

#delete(symbol) ⇒ Object

Resets a config option to its default.

Parameters

symbol<Symbol>

Name of the config option



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# File 'lib/mixlib/config.rb', line 103

def delete(symbol)
  self.configuration.delete(symbol)
end

#from_file(filename) ⇒ Object

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



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# File 'lib/mixlib/config.rb', line 46

def from_file(filename)
  self.instance_eval(IO.read(filename), filename, 1)
end

#has_key?(key) ⇒ Boolean

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

Returns:

  • (Boolean) 


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# File 'lib/mixlib/config.rb', line 95

def has_key?(key)
  self.configuration.has_key?(key.to_sym)
end

#hash_dup ⇒ Object

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



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# File 'lib/mixlib/config.rb', line 223

def hash_dup
  save
end

#keys ⇒ Object

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



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# File 'lib/mixlib/config.rb', line 213

def keys
  self.configuration.keys
end

#merge!(hash) ⇒ Object

Merge an incoming hash with our config options

Parameters

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

Returns

self



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# File 'lib/mixlib/config.rb', line 194

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

#reset ⇒ Object

Resets all config options to their defaults.



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# File 'lib/mixlib/config.rb', line 108

def reset
  self.configuration = Hash.new
  self.config_contexts.values.each { |config_context| config_context.reset }
end

#restore(hash) ⇒ Object

Restore non-default values from the given hash.

This method is the equivalent of reset followed by merge!(hash).

Parameters

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

Returns

self



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# File 'lib/mixlib/config.rb', line 182

def restore(hash)
  reset
  merge!(hash)
end

#save(include_defaults = false) ⇒ Object

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
  }
}



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# File 'lib/mixlib/config.rb', line 156

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