path: root/lib/puppet/provider.rb

# The container class for implementations.
class Puppet::Provider
  include Puppet::Util
  include Puppet::Util::Errors
  include Puppet::Util::Warnings
  extend Puppet::Util::Warnings

  require 'puppet/provider/confiner'

  extend Puppet::Provider::Confiner

  Puppet::Util.logmethods(self, true)

  class << self
    # Include the util module so we have access to things like 'which'
    include Puppet::Util, Puppet::Util::Docs
    include Puppet::Util::Logging
    attr_accessor :name

    # The source parameter exists so that providers using the same
    # source can specify this, so reading doesn't attempt to read the
    # same package multiple times.
    attr_writer :source

    # LAK 2007-05-09: Keep the model stuff around for backward compatibility
    attr_reader :model
    attr_accessor :resource_type
    attr_writer :doc
  end

  # LAK 2007-05-09: Keep the model stuff around for backward compatibility
  attr_reader :model
  attr_accessor :resource

  def self.command(name)
    name = symbolize(name)

    if defined?(@commands) and command = @commands[name]
      # nothing
    elsif superclass.respond_to? :command and command = superclass.command(name)
      # nothing
    else
      raise Puppet::DevError, "No command #{name} defined for provider #{self.name}"
    end

    which(command)
  end

  # Define commands that are not optional.
  def self.commands(hash)
    optional_commands(hash) do |name, path|
      confine :exists => path, :for_binary => true
    end
  end

  # Is the provided feature a declared feature?
  def self.declared_feature?(name)
    defined?(@declared_features) and @declared_features.include?(name)
  end

  # Does this implementation match all of the default requirements?  If
  # defaults are empty, we return false.
  def self.default?
    return false if @defaults.empty?
    if @defaults.find do |fact, values|
        values = [values] unless values.is_a? Array
        if fval = Facter.value(fact).to_s and fval != ""
          fval = fval.to_s.downcase.intern
        else
          return false
        end

        # If any of the values match, we're a default.
        if values.find do |value| fval == value.to_s.downcase.intern end
          false
        else
          true
        end
      end
      return false
    else
      return true
    end
  end

  # Store how to determine defaults.
  def self.defaultfor(hash)
    hash.each do |d,v|
      @defaults[d] = v
    end
  end

  def self.specificity
    (@defaults.length * 100) + ancestors.select { |a| a.is_a? Class }.length
  end

  def self.initvars
    @defaults = {}
    @commands = {}
  end

  # The method for returning a list of provider instances.  Note that it returns providers, preferably with values already
  # filled in, not resources.
  def self.instances
    raise Puppet::DevError, "Provider #{self.name} has not defined the 'instances' class method"
  end

  # Create the methods for a given command.
  def self.make_command_methods(name)
    # Now define a method for that command
    unless singleton_class.method_defined?(name)
      meta_def(name) do |*args|
        raise Puppet::Error, "Command #{name} is missing" unless command(name)
        if args.empty?
          cmd = [command(name)]
        else
          cmd = [command(name)] + args
        end
        # This might throw an ExecutionFailure, but the system above
        # will catch it, if so.
        return execute(cmd)
      end

      # And then define an instance method that just calls the class method.
      # We need both, so both instances and classes can easily run the commands.
      unless method_defined?(name)
        define_method(name) do |*args|
          self.class.send(name, *args)
        end
      end
    end
  end

  # Create getter/setter methods for each property our resource type supports.
  # They all get stored in @property_hash.  This method is useful
  # for those providers that use prefetch and flush.
  def self.mkmodelmethods
    warnonce "Provider.mkmodelmethods is deprecated; use Provider.mk_resource_methods"
    mk_resource_methods
  end

  # Create getter/setter methods for each property our resource type supports.
  # They all get stored in @property_hash.  This method is useful
  # for those providers that use prefetch and flush.
  def self.mk_resource_methods
    [resource_type.validproperties, resource_type.parameters].flatten.each do |attr|
      attr = symbolize(attr)
      next if attr == :name
      define_method(attr) do
        @property_hash[attr] || :absent
      end

      define_method(attr.to_s + "=") do |val|
        @property_hash[attr] = val
      end
    end
  end

  self.initvars

  # Define one or more binaries we'll be using.  If a block is passed, yield the name
  # and path to the block (really only used by 'commands').
  def self.optional_commands(hash)
    hash.each do |name, path|
      name = symbolize(name)
      @commands[name] = path

      yield(name, path) if block_given?

      # Now define the class and instance methods.
      make_command_methods(name)
    end
  end

  # Retrieve the data source.  Defaults to the provider name.
  def self.source
    @source ||= self.name
  end

  # Does this provider support the specified parameter?
  def self.supports_parameter?(param)
    if param.is_a?(Class)
      klass = param
    else
      unless klass = resource_type.attrclass(param)
        raise Puppet::DevError, "'#{param}' is not a valid parameter for #{resource_type.name}"
      end
    end
    return true unless features = klass.required_features

    !!satisfies?(*features)
  end

#    def self.to_s
#        unless defined?(@str)
#            if self.resource_type
#                @str = "#{resource_type.name} provider #{self.name}"
#            else
#                @str = "unattached provider #{self.name}"
#            end
#        end
#        @str
#    end

  dochook(:defaults) do
    if @defaults.length > 0
      return "  Default for " + @defaults.collect do |f, v|
        "`#{f}` == `#{v}`"
      end.join(" and ") + "."
    end
  end

  dochook(:commands) do
    if @commands.length > 0
      return "  Required binaries: " + @commands.collect do |n, c|
        "`#{c}`"
      end.join(", ") + "."
    end
  end

  dochook(:features) do
    if features.length > 0
      return "  Supported features: " + features.collect do |f|
        "`#{f}`"
      end.join(", ") + "."
    end
  end

  # Remove the reference to the resource, so GC can clean up.
  def clear
    @resource = nil
    @model = nil
  end

  # Retrieve a named command.
  def command(name)
    self.class.command(name)
  end

  # Get a parameter value.
  def get(param)
    @property_hash[symbolize(param)] || :absent
  end

  def initialize(resource = nil)
    if resource.is_a?(Hash)
      # We don't use a duplicate here, because some providers (ParsedFile, at least)
      # use the hash here for later events.
      @property_hash = resource
    elsif resource
      @resource = resource
      # LAK 2007-05-09: Keep the model stuff around for backward compatibility
      @model = resource
      @property_hash = {}
    else
      @property_hash = {}
    end
  end

  def name
    if n = @property_hash[:name]
      return n
    elsif self.resource
      resource.name
    else
      raise Puppet::DevError, "No resource and no name in property hash in #{self.class.name} instance"
    end
  end

  # Set passed params as the current values.
  def set(params)
    params.each do |param, value|
      @property_hash[symbolize(param)] = value
    end
  end

  def to_s
    "#{@resource}(provider=#{self.class.name})"
  end
end