class ChefCompat::CopiedFromChef::Chef::Property

Type and validation information for a property on a resource.

A property named “x” manipulates the “@x” instance variable on a resource. The presence of the variable (`instance_variable_defined?(@x)`) tells whether the variable is defined; it may have any actual value, constrained only by validation.

Properties may have validation, defaults, and coercion, and have full support for lazy values.

@see Chef::Resource.property @see Chef::DelayedEvaluator

Attributes

options[R]

The options this Property will use for get/set behavior and validation.

@see initialize for a list of valid options.

Public Class Methods

derive(**options) click to toggle source

Create a reusable property type that can be used in multiple properties in different resources.

@param options [Hash<Symbol,Object>] Validation options. See Chef::Resource.property for

the list of options.

@example

Property.derive(default: 'hi')
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 55
def self.derive(**options)
  new(**options)
end
new(**options) click to toggle source

Create a new property.

@param options [Hash<Symbol,Object>] Property options, including

control options here, as well as validation options (see
Chef::Mixin::ParamsValidate#validate for a description of validation
options).
@option options [Symbol] :name The name of this property.
@option options [Class] :declared_in The class this property comes from.
@option options [Symbol] :instance_variable_name The instance variable
  tied to this property. Must include a leading `@`. Defaults to `@<name>`.
  `nil` means the property is opaque and not tied to a specific instance
  variable.
@option options [Boolean] :desired_state `true` if this property is part of desired
  state. Defaults to `true`.
@option options [Boolean] :identity `true` if this property is part of object
  identity. Defaults to `false`.
@option options [Boolean] :name_property `true` if this
  property defaults to the same value as `name`. Equivalent to
  `default: lazy { name }`, except that #property_is_set? will
  return `true` if the property is set *or* if `name` is set.
@option options [Boolean] :nillable `true` opt-in to Chef-13 style behavior where
  attempting to set a nil value will really set a nil value instead of issuing
  a warning and operating like a getter
@option options [Object] :default The value this property
  will return if the user does not set one. If this is `lazy`, it will
  be run in the context of the instance (and able to access other
  properties) and cached. If not, the value will be frozen with Object#freeze
  to prevent users from modifying it in an instance.
@option options [Proc] :coerce A proc which will be called to
  transform the user input to canonical form. The value is passed in,
  and the transformed value returned as output. Lazy values will *not*
  be passed to this method until after they are evaluated. Called in the
  context of the resource (meaning you can access other properties).
@option options [Boolean] :required `true` if this property
  must be present; `false` otherwise. This is checked after the resource
  is fully initialized.
Calls superclass method
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 97
    def initialize(**options)
super if defined?(::Chef::Property)
      options = options.inject({}) { |memo, (key, value)| memo[key.to_sym] = value; memo }
      @options = options
      options[:name] = options[:name].to_sym if options[:name]
      options[:instance_variable_name] = options[:instance_variable_name].to_sym if options[:instance_variable_name]

      # Replace name_attribute with name_property
      if options.has_key?(:name_attribute)
        # If we have both name_attribute and name_property and they differ, raise an error
        if options.has_key?(:name_property)
          raise ArgumentError, "Cannot specify both name_property and name_attribute together on property #{self}."
        end
        # replace name_property with name_attribute in place
        options = Hash[options.map { |k, v| k == :name_attribute ? [ :name_property, v ] : [ k, v ] }]
        @options = options
      end

      # Only pick the first of :default, :name_property and :name_attribute if
      # more than one is specified.
      if options.has_key?(:default) && options[:name_property]
        if options[:default].nil? || options.keys.index(:name_property) < options.keys.index(:default)
          options.delete(:default)
          preferred_default = :name_property
        else
          options.delete(:name_property)
          preferred_default = :default
        end
        Chef.log_deprecation("Cannot specify both default and name_property together on property #{self}. Only one (#{preferred_default}) will be obeyed. In Chef 13, this will become an error. Please remove one or the other from the property.")
      end

      # Validate the default early, so the user gets a good error message, and
      # cache it so we don't do it again if so
      begin
        # If we can validate it all the way to output, do it.
        @stored_default = input_to_stored_value(nil, default, is_default: true)
      rescue Chef::Exceptions::CannotValidateStaticallyError
        # If the validation is not static (i.e. has procs), we will have to
        # coerce and validate the default each time we run
      end
    end

Public Instance Methods

call(resource, value = NOT_PASSED) click to toggle source

Handle the property being called.

The base implementation does the property get-or-set:

“`ruby resource.myprop # get resource.myprop value # set “`

Subclasses may implement this with any arguments they want, as long as the corresponding DSL calls it correctly.

@param resource [Chef::Resource] The resource to get the property from. @param value The value to set (or NOT_PASSED if it is a get).

@return The current value of the property. If it is a `set`, lazy values

will be returned without running, validating or coercing. If it is a
`get`, the non-lazy, coerced, validated value will always be returned.
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 269
def call(resource, value = NOT_PASSED)
  if value == NOT_PASSED
    return get(resource)
  end

  if value.nil? && !nillable?
    # In Chef 12, value(nil) does a *get* instead of a set, so we
    # warn if the value would have been changed. In Chef 13, it will be
    # equivalent to value = nil.
    result = get(resource, nil_set: true)

    # Warn about this becoming a set in Chef 13.
    begin
      input_to_stored_value(resource, value)
      # If nil is valid, and it would change the value, warn that this will change to a set.
      if !result.nil?
        Chef.log_deprecation("An attempt was made to change #{name} from #{result.inspect} to nil by calling #{name}(nil). In Chef 12, this does a get rather than a set. In Chef 13, this will change to set the value to nil.")
      end
    rescue Chef::Exceptions::DeprecatedFeatureError
      raise
    rescue
      # If nil is invalid, warn that this will become an error.
      Chef.log_deprecation("nil is an invalid value for #{self}. In Chef 13, this warning will change to an error. Error: #{$!}")
    end

    result
  else
    # Anything else, such as myprop(value) is a set
    set(resource, value)
  end
end
coerce(resource, value) click to toggle source

Coerce an input value into canonical form for the property.

After coercion, the value is suitable for storage in the resource. You must validate values after coercion, however.

Does no special handling for lazy values.

@param resource [Chef::Resource] The resource we're coercing against

(to provide context for the coerce).

@param value The value to coerce.

@return The coerced value.

@raise Chef::Exceptions::ValidationFailed If the value is invalid for

this property.
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 449
def coerce(resource, value)
  if options.has_key?(:coerce)
    # If we have no default value, `nil` is never coerced or validated
    unless !has_default? && value.nil?
      value = exec_in_resource(resource, options[:coerce], value)
    end
  end
  value
end
declared_in() click to toggle source

The class this property was defined in.

@return [Class]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 157
def declared_in
  options[:declared_in]
end
default() click to toggle source

The raw default value for this resource.

Does not coerce or validate the default. Does not evaluate lazy values.

Defaults to `lazy { name }` if name_property is true; otherwise defaults to `nil`

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 184
def default
  return options[:default] if options.has_key?(:default)
  return Chef::DelayedEvaluator.new { name } if name_property?
  nil
end
derive(**modified_options) click to toggle source

Derive a new Property that is just like this one, except with some added or changed options.

@param options [Hash<Symbol,Object>] List of options that would be passed

to #initialize.

@return [Property] The new property type.

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 493
def derive(**modified_options)
  # Since name_property, name_attribute and default override each other,
  # if you specify one of them in modified_options it overrides anything in
  # the original options.
  options = self.options
  if modified_options.has_key?(:name_property) ||
      modified_options.has_key?(:name_attribute) ||
      modified_options.has_key?(:default)
    options = options.reject { |k, v| k == :name_attribute || k == :name_property || k == :default }
  end
  self.class.new(options.merge(modified_options))
end
desired_state?() click to toggle source

Whether this is part of desired state or not.

Defaults to true.

@return [Boolean]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 206
def desired_state?
  return true if !options.has_key?(:desired_state)
  options[:desired_state]
end
emit_dsl() click to toggle source

Emit the DSL for this property into the resource class (`declared_in`).

Creates a getter and setter for the property.

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 511
    def emit_dsl
      # We don't create the getter/setter if it's a custom property; we will
      # be using the existing getter/setter to manipulate it instead.
      return if !instance_variable_name

      # We prefer this form because the property name won't show up in the
      # stack trace if you use `define_method`.
      declared_in.class_eval <<-EOM, __FILE__, __LINE__ + 1
        def #{name}(value=NOT_PASSED)
          raise "Property #{name} of \#{self} cannot be passed a block! If you meant to create a resource named #{name} instead, you'll need to first rename the property." if block_given?
          self.class.properties[#{name.inspect}].call(self, value)
        end
        def #{name}=(value)
          raise "Property #{name} of \#{self} cannot be passed a block! If you meant to create a resource named #{name} instead, you'll need to first rename the property." if block_given?
          self.class.properties[#{name.inspect}].set(self, value)
        end
      EOM
    rescue SyntaxError
      # If the name is not a valid ruby name, we use define_method.
      declared_in.define_method(name) do |value = NOT_PASSED, &block|
        raise "Property #{name} of #{self} cannot be passed a block! If you meant to create a resource named #{name} instead, you'll need to first rename the property." if block
        self.class.properties[name].call(self, value)
      end
      declared_in.define_method("#{name}=") do |value, &block|
        raise "Property #{name} of #{self} cannot be passed a block! If you meant to create a resource named #{name} instead, you'll need to first rename the property." if block
        self.class.properties[name].set(self, value)
      end
    end
explicitly_accepts_nil?(resource) click to toggle source

Find out whether this type accepts nil explicitly.

A type accepts nil explicitly if “is” allows nil, it validates as nil, and is not simply an empty type.

A type is presumed to accept nil if it does coercion (which must handle nil).

These examples accept nil explicitly: “`ruby property :a, [ String, nil ] property :a, [ String, NilClass ] property :a, [ String, proc { |v| v.nil? } ] “`

This does not (because the “is” doesn't exist or doesn't have nil):

“`ruby property :x, String “`

These do not, even though nil would validate fine (because they do not have “is”):

“`ruby property :a property :a, equal_to: [ 1, 2, 3, nil ] property :a, kind_of: [ String, NilClass ] property :a, respond_to: [ ] property :a, callbacks: { “a” => proc { |v| v.nil? } } “`

@param resource [Chef::Resource] The resource we're coercing against

(to provide context for the coerce).

@return [Boolean] Whether this value explicitly accepts nil.

@api private

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 585
def explicitly_accepts_nil?(resource)
  options.has_key?(:coerce) ||
    (options.has_key?(:is) && resource.send(:_pv_is, { name => nil }, name, options[:is], raise_error: false))
end
get(resource, nil_set: false) click to toggle source

Get the property value from the resource, handling lazy values, defaults, and validation.

  • If the property's value is lazy, it is evaluated, coerced and validated.

  • If the property has no value, and is required, raises ValidationFailed.

  • If the property has no value, but has a lazy default, it is evaluated, coerced and validated. If the evaluated value is frozen, the resulting

  • If the property has no value, but has a default, the default value will be returned and frozen. If the default value is lazy, it will be evaluated, coerced and validated, and the result stored in the property.

  • If the property has no value, but is name_property, `resource.name` is retrieved, coerced, validated and stored in the property.

  • Otherwise, `nil` is returned.

@param resource [Chef::Resource] The resource to get the property from.

@return The value of the property.

@raise Chef::Exceptions::ValidationFailed If the value is invalid for

this property, or if the value is required and not set.
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 323
def get(resource, nil_set: false)
  # If it's set, return it (and evaluate any lazy values)
  if is_set?(resource)
    value = get_value(resource)
    value = stored_value_to_output(resource, value)

  else
    # We are getting the default value.

    # If the user does something like this:
    #
    # ```
    # class MyResource < Chef::Resource
    #   property :content
    #   action :create do
    #     file '/x.txt' do
    #       content content
    #     end
    #   end
    # end
    # ```
    #
    # It won't do what they expect. This checks whether you try to *read*
    # `content` while we are compiling the resource.
    if !nil_set &&
        resource.respond_to?(:resource_initializing) &&
        resource.resource_initializing &&
        resource.respond_to?(:enclosing_provider) &&
        resource.enclosing_provider &&
        resource.enclosing_provider.new_resource &&
        resource.enclosing_provider.new_resource.respond_to?(name)
      Chef::Log.warn("#{Chef::Log.caller_location}: property #{name} is declared in both #{resource} and #{resource.enclosing_provider}. Use new_resource.#{name} instead. At #{Chef::Log.caller_location}")
    end

    if has_default?
      # If we were able to cache the stored_default, grab it.
      if defined?(@stored_default)
        value = @stored_default
      else
        # Otherwise, we have to validate it now.
        value = input_to_stored_value(resource, default, is_default: true)
      end
      value = stored_value_to_output(resource, value, is_default: true)

      # If the value is mutable (non-frozen), we set it on the instance
      # so that people can mutate it.  (All constant default values are
      # frozen.)
      if !value.frozen? && !value.nil?
        set_value(resource, value)
      end

      value

    elsif required?
      raise Chef::Exceptions::ValidationFailed, "#{name} is required"
    end
  end
end
get_value(resource) click to toggle source

@api private

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 591
def get_value(resource)
  if instance_variable_name
    resource.instance_variable_get(instance_variable_name)
  else
    resource.send(name)
  end
end
has_default?() click to toggle source

Whether this property has a default value.

@return [Boolean]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 225
def has_default?
  options.has_key?(:default) || name_property?
end
identity?() click to toggle source

Whether this is part of the resource's natural identity or not.

@return [Boolean]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 195
def identity?
  options[:identity]
end
instance_variable_name() click to toggle source

The instance variable associated with this property.

Defaults to `@<name>`

@return [Symbol]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 168
def instance_variable_name
  if options.has_key?(:instance_variable_name)
    options[:instance_variable_name]
  elsif name
    :"@#{name}"
  end
end
is_set?(resource) click to toggle source

Find out whether this property has been set.

This will be true if:

  • The user explicitly set the value

  • The property has a default, and the value was retrieved.

From this point of view, it is worth looking at this as “what does the user think this value should be.” In order words, if the user grabbed the value, even if it was a default, they probably based calculations on it. If they based calculations on it and the value changes, the rest of the world gets inconsistent.

@param resource [Chef::Resource] The resource to get the property from.

@return [Boolean]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 418
def is_set?(resource)
  value_is_set?(resource)
end
name() click to toggle source

The name of this property.

@return [String]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 148
def name
  options[:name]
end
name_property?() click to toggle source

Whether this is name_property or not.

@return [Boolean]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 216
def name_property?
  options[:name_property]
end
required?() click to toggle source

Whether this property is required or not.

@return [Boolean]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 234
def required?
  options[:required]
end
reset(resource) click to toggle source

Reset the value of this property so that is_set? will return false and the default will be returned in the future.

@param resource [Chef::Resource] The resource to get the property from.

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 428
def reset(resource)
  reset_value(resource)
end
reset_value(resource) click to toggle source

@api private

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 618
def reset_value(resource)
  if instance_variable_name
    if value_is_set?(resource)
      resource.remove_instance_variable(instance_variable_name)
    end
  else
    raise ArgumentError, "Property #{name} has no instance variable defined and cannot be reset"
  end
end
set(resource, value) click to toggle source

Set the value of this property in the given resource.

Non-lazy values are coerced and validated before being set. Coercion and validation of lazy values is delayed until they are first retrieved.

@param resource [Chef::Resource] The resource to set this property in. @param value The value to set.

@return The value that was set, after coercion (if lazy, still returns

the lazy value)

@raise Chef::Exceptions::ValidationFailed If the value is invalid for

this property.
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 397
def set(resource, value)
  set_value(resource, input_to_stored_value(resource, value))
end
set_value(resource, value) click to toggle source

@api private

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 600
def set_value(resource, value)
  if instance_variable_name
    resource.instance_variable_set(instance_variable_name, value)
  else
    resource.send(name, value)
  end
end
to_s() click to toggle source
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 139
def to_s
  "#{name || "<property type>"}#{declared_in ? " of resource #{declared_in.resource_name}" : ""}"
end
validate(resource, value) click to toggle source

Validate a value.

Calls Chef::Mixin::ParamsValidate#validate with validation_options as options.

@param resource [Chef::Resource] The resource we're validating against

(to provide context for the validate).

@param value The value to validate.

@raise Chef::Exceptions::ValidationFailed If the value is invalid for

this property.
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 472
def validate(resource, value)
  # If we have no default value, `nil` is never coerced or validated
  unless value.nil? && !has_default?
    if resource
      resource.validate({ name => value }, { name => validation_options })
    else
      name = self.name || :property_type
      Chef::Mixin::ParamsValidate.validate({ name => value }, { name => validation_options })
    end
  end
end
validation_options() click to toggle source

Validation options. (See Chef::Mixin::ParamsValidate#validate.)

@return [Hash<Symbol,Object>]

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 243
def validation_options
  @validation_options ||= options.reject { |k, v|
    [:declared_in, :name, :instance_variable_name, :desired_state, :identity, :default, :name_property, :coerce, :required, :nillable].include?(k)
  }
end
value_is_set?(resource) click to toggle source

@api private

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 609
def value_is_set?(resource)
  if instance_variable_name
    resource.instance_variable_defined?(instance_variable_name)
  else
    true
  end
end

Private Instance Methods

coerce_and_validate(resource, value, is_default: false) click to toggle source

Coerces and validates the value. If the value is a default, it will warn the user that invalid defaults are bad mmkay, and return it as if it were valid.

# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 662
def coerce_and_validate(resource, value, is_default: false)
  result = coerce(resource, value)
  begin
    # If the input is from a default, we need to emit an invalid default warning on validate.
    validate(resource, result)
  rescue Chef::Exceptions::CannotValidateStaticallyError
    # This one gets re-raised
    raise
  rescue
    # Anything else is just an invalid default: in those cases, we just
    # warn and return the (possibly coerced) value to the user.
    if is_default
      if value.nil?
        Chef.log_deprecation("Default value nil is invalid for property #{self}. Possible fixes: 1. Remove 'default: nil' if nil means 'undefined'. 2. Set a valid default value if there is a reasonable one. 3. Allow nil as a valid value of your property (for example, 'property #{name.inspect}, [ String, nil ], default: nil'). Error: #{$!}")
      else
        Chef.log_deprecation("Default value #{value.inspect} is invalid for property #{self}. In Chef 13 this will become an error: #{$!}.")
      end
    else
      raise
    end
  end

  result
end
exec_in_resource(resource, proc, *args) click to toggle source
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 630
def exec_in_resource(resource, proc, *args)
  if resource
    if proc.arity > args.size
      value = proc.call(resource, *args)
    else
      value = resource.instance_exec(*args, &proc)
    end
  else
    # If we don't have a resource yet, we can't exec in resource!
    raise Chef::Exceptions::CannotValidateStaticallyError, "Cannot validate or coerce without a resource"
  end
end
input_to_stored_value(resource, value, is_default: false) click to toggle source
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 643
def input_to_stored_value(resource, value, is_default: false)
  unless value.is_a?(DelayedEvaluator)
    value = coerce_and_validate(resource, value, is_default: is_default)
  end
  value
end
nillable?() click to toggle source
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 687
def nillable?
  !!options[:nillable]
end
stored_value_to_output(resource, value, is_default: false) click to toggle source
# File files/lib/chef_compat/copied_from_chef/chef/property.rb, line 650
def stored_value_to_output(resource, value, is_default: false)
  # Crack open lazy values before giving the result to the user
  if value.is_a?(DelayedEvaluator)
    value = exec_in_resource(resource, value)
    value = coerce_and_validate(resource, value, is_default: is_default)
  end
  value
end