path: root/lib/puppet/parameter.rb

require 'puppet/util/methodhelper'
require 'puppet/util/log_paths'
require 'puppet/util/logging'
require 'puppet/util/docs'
require 'puppet/util/cacher'

class Puppet::Parameter
    include Puppet::Util
    include Puppet::Util::Errors
    include Puppet::Util::LogPaths
    include Puppet::Util::Logging
    include Puppet::Util::MethodHelper
    include Puppet::Util::Cacher

    require 'puppet/parameter/value_collection'

    class << self
        include Puppet::Util
        include Puppet::Util::Docs
        attr_reader :validater, :munger, :name, :default, :required_features, :value_collection
        attr_accessor :metaparam

        # Define the default value for a given parameter or parameter.  This
        # means that 'nil' is an invalid default value.  This defines
        # the 'default' instance method.
        def defaultto(value = nil, &block)
            if block
                define_method(:default, &block)
            else
                if value.nil?
                    raise Puppet::DevError,
                        "Either a default value or block must be provided"
                end
                define_method(:default) do value end
            end
        end

        # Return a documentation string.  If there are valid values,
        # then tack them onto the string.
        def doc
            @doc ||= ""

            unless defined? @addeddocvals
                @doc += value_collection.doc

                if f = self.required_features
                    @doc += "  Requires features %s." % f.flatten.collect { |f| f.to_s }.join(" ")
                end
                @addeddocvals = true
            end

            @doc
        end

        def nodefault
            if public_method_defined? :default
                undef_method :default
            end
        end

        # Store documentation for this parameter.
        def desc(str)
            @doc = str
        end

        def initvars
            @value_collection = ValueCollection.new
        end

        # This is how we munge the value.  Basically, this is our
        # opportunity to convert the value from one form into another.
        def munge(&block)
            # I need to wrap the unsafe version in begin/rescue parameterments,
            # but if I directly call the block then it gets bound to the
            # class's context, not the instance's, thus the two methods,
            # instead of just one.
            define_method(:unsafe_munge, &block)
        end

        # Does the parameter supports reverse munge?
        # This will be called when something wants to access the parameter
        # in a canonical form different to what the storage form is.
        def unmunge(&block)
            define_method(:unmunge, &block)
        end

        # Optionaly convert the value to a canonical form so that it will
        # be found in hashes, etc.  Mostly useful for namevars.
        def to_canonicalize(&block)
            metaclass = (class << self; self; end)
            metaclass.send(:define_method,:canonicalize,&block)
        end

        # Mark whether we're the namevar.
        def isnamevar
            @isnamevar = true
            @required = true
        end

        # Is this parameter the namevar?  Defaults to false.
        def isnamevar?
            if defined? @isnamevar
                return @isnamevar
            else
                return false
            end
        end

        # This parameter is required.
        def isrequired
            @required = true
        end

        # Specify features that are required for this parameter to work.
        def required_features=(*args)
            @required_features = args.flatten.collect { |a| a.to_s.downcase.intern }
        end

        # Is this parameter required?  Defaults to false.
        def required?
            if defined? @required
                return @required
            else
                return false
            end
        end

        # Verify that we got a good value
        def validate(&block)
            define_method(:unsafe_validate, &block)
        end

        # Define a new value for our parameter.
        def newvalues(*names)
            @value_collection.newvalues(*names)
        end

        def aliasvalue(name, other)
            @value_collection.aliasvalue(name, other)
        end
    end

    # Just a simple method to proxy instance methods to class methods
    def self.proxymethods(*values)
        values.each { |val|
            define_method(val) do
                self.class.send(val)
            end
        }
    end

    # And then define one of these proxies for each method in our
    # ParamHandler class.
    proxymethods("required?", "isnamevar?")

    attr_accessor :resource
    # LAK 2007-05-09: Keep the @parent around for backward compatibility.
    attr_accessor :parent

    [:line, :file, :version].each do |param|
        define_method(param) do
            resource.send(param)
        end
    end

    def devfail(msg)
        self.fail(Puppet::DevError, msg)
    end

    def expirer
        resource.catalog
    end

    def fail(*args)
        type = nil
        if args[0].is_a?(Class)
            type = args.shift
        else
            type = Puppet::Error
        end

        error = type.new(args.join(" "))

        if defined? @resource and @resource and @resource.line
            error.line = @resource.line
        end

        if defined? @resource and @resource and @resource.file
            error.file = @resource.file
        end

        raise error
    end

    # Basic parameter initialization.
    def initialize(options = {})
        options = symbolize_options(options)
        if resource = options[:resource]
            self.resource = resource
            options.delete(:resource)
        else
            raise Puppet::DevError, "No resource set for %s" % self.class.name
        end

        set_options(options)
    end

    def log(msg)
        send_log(resource[:loglevel], msg)
    end

    # Is this parameter a metaparam?
    def metaparam?
        self.class.metaparam
    end

    # each parameter class must define the name() method, and parameter
    # instances do not change that name this implicitly means that a given
    # object can only have one parameter instance of a given parameter
    # class
    def name
        return self.class.name
    end

    # for testing whether we should actually do anything
    def noop
        unless defined? @noop
            @noop = false
        end
        tmp = @noop || self.resource.noop || Puppet[:noop] || false
        #debug "noop is %s" % tmp
        return tmp
    end

    # return the full path to us, for logging and rollback; not currently
    # used
    def pathbuilder
        if defined? @resource and @resource
            return [@resource.pathbuilder, self.name]
        else
            return [self.name]
        end
    end

    # If the specified value is allowed, then munge appropriately.
    # If the developer uses a 'munge' hook, this method will get overridden.
    def unsafe_munge(value)
        self.class.value_collection.munge(value)
    end

    # no unmunge by default
    def unmunge(value)
        value
    end

    # Assume the value is already in canonical form by default
    def self.canonicalize(value)
        value
    end

    def canonicalize(value)
        self.class.canonicalize(value)
    end

    # A wrapper around our munging that makes sure we raise useful exceptions.
    def munge(value)
        begin
            ret = unsafe_munge(canonicalize(value))
        rescue Puppet::Error => detail
            Puppet.debug "Reraising %s" % detail
            raise
        rescue => detail
            raise Puppet::DevError, "Munging failed for value %s in class %s: %s" % [value.inspect, self.name, detail], detail.backtrace
        end
        ret
    end

    # Verify that the passed value is valid.
    # If the developer uses a 'validate' hook, this method will get overridden.
    def unsafe_validate(value)
        self.class.value_collection.validate(value)
    end

    # A protected validation method that only ever raises useful exceptions.
    def validate(value)
        begin
            unsafe_validate(value)
        rescue ArgumentError => detail
            fail detail.to_s
        rescue Puppet::Error, TypeError
            raise
        rescue => detail
            raise Puppet::DevError, "Validate method failed for class %s: %s" % [self.name, detail], detail.backtrace
        end
    end

    def remove
        @resource = nil
    end

    def value
        unmunge(@value)
    end

    # Store the value provided.  All of the checking should possibly be
    # late-binding (e.g., users might not exist when the value is assigned
    # but might when it is asked for).
    def value=(value)
        validate(value)

        @value = munge(value)
    end

    # Retrieve the resource's provider.  Some types don't have providers, in which
    # case we return the resource object itself.
    def provider
        @resource.provider
    end

    # The properties need to return tags so that logs correctly collect them.
    def tags
        unless defined? @tags
            @tags = []
            # This might not be true in testing
            if @resource.respond_to? :tags
                @tags = @resource.tags
            end
            @tags << self.name.to_s
        end
        @tags
    end

    def to_s
        name.to_s
    end
end