#
# Author:: John Keiser <jkeiser@chef.io>
# Copyright:: Copyright 2015-2016, John Keiser.
# 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.
#
require "chef/exceptions"
require "chef/delayed_evaluator"
require "chef/chef_class"
require "chef/log"
class Chef
#
# 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
#
class Property
#
# 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')
#
def self.derive(**options)
new(**options)
end
#
# 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.
#
def initialize(**options)
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
def to_s
"#{name || "<property type>"}#{declared_in ? " of resource #{declared_in.resource_name}" : ""}"
end
#
# The name of this property.
#
# @return [String]
#
def name
options[:name]
end
#
# The class this property was defined in.
#
# @return [Class]
#
def declared_in
options[:declared_in]
end
#
# The instance variable associated with this property.
#
# Defaults to `@<name>`
#
# @return [Symbol]
#
def instance_variable_name
if options.has_key?(:instance_variable_name)
options[:instance_variable_name]
elsif name
:"@#{name}"
end
end
#
# 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`
#
def default
return options[:default] if options.has_key?(:default)
return Chef::DelayedEvaluator.new { name } if name_property?
nil
end
#
# Whether this is part of the resource's natural identity or not.
#
# @return [Boolean]
#
def identity?
options[:identity]
end
#
# Whether this is part of desired state or not.
#
# Defaults to true.
#
# @return [Boolean]
#
def desired_state?
return true if !options.has_key?(:desired_state)
options[:desired_state]
end
#
# Whether this is name_property or not.
#
# @return [Boolean]
#
def name_property?
options[:name_property]
end
#
# Whether this property has a default value.
#
# @return [Boolean]
#
def has_default?
options.has_key?(:default) || name_property?
end
#
# Whether this property is required or not.
#
# @return [Boolean]
#
def required?
options[:required]
end
#
# Validation options. (See Chef::Mixin::ParamsValidate#validate.)
#
# @return [Hash<Symbol,Object>]
#
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
#
# 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.
#
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
#
# 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.
#
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
#
# 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.
#
def set(resource, value)
set_value(resource, input_to_stored_value(resource, value))
end
#
# 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]
#
def is_set?(resource)
value_is_set?(resource)
end
#
# 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.
#
def reset(resource)
reset_value(resource)
end
#
# 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.
#
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
#
# 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.
#
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
#
# 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.
#
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
#
# Emit the DSL for this property into the resource class (`declared_in`).
#
# Creates a getter and setter for the property.
#
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
protected
#
# The options this Property will use for get/set behavior and validation.
#
# @see #initialize for a list of valid options.
#
attr_reader :options
#
# 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
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
def get_value(resource)
if instance_variable_name
resource.instance_variable_get(instance_variable_name)
else
resource.send(name)
end
end
def set_value(resource, value)
if instance_variable_name
resource.instance_variable_set(instance_variable_name, value)
else
resource.send(name, value)
end
end
def value_is_set?(resource)
if instance_variable_name
resource.instance_variable_defined?(instance_variable_name)
else
true
end
end
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
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
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
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
# 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.
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
def nillable?
!!options[:nillable]
end
end
end