Class: Puppet::Indirector::Indirection

Inherits:
Object
  • Object
show all
Includes:
Util::Docs
Defined in:
lib/puppet/indirector/indirection.rb

Overview

The class that connects functional classes with their different collection back-ends. Each indirection has a set of associated terminus classes, each of which is a subclass of Puppet::Indirector::Terminus.

Constant Summary collapse

@@indirections =
[]

Constants included from Util::Docs

Util::Docs::HEADER_LEVELS

Instance Attribute Summary collapse

Attributes included from Util::Docs

#nodoc

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Util::Docs

#desc, #dochook, #doctable, #markdown_definitionlist, #markdown_header, #nodoc?, #pad, scrub

Constructor Details

#initialize(model, name, doc: nil, indirected_class: nil, cache_class: nil, terminus_class: nil, terminus_setting: nil, extend: nil) ⇒ Indirection

Returns a new instance of Indirection

Raises:

  • (ArgumentError)

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# File 'lib/puppet/indirector/indirection.rb', line 95

def initialize(model, name, doc: nil, indirected_class: nil, cache_class: nil, terminus_class: nil, terminus_setting: nil, extend: nil)
  @model = model
  @name = name
  @termini = {}

  @doc = doc

  raise(ArgumentError, _("Indirection %{name} is already defined") % { name: @name }) if @@indirections.find { |i| i.name == @name }
  @@indirections << self

  @indirected_class = indirected_class
  self.extend(extend) if extend

  # Setting these depend on the indirection already being installed so they have to be at the end
  set_global_setting(:cache_class, cache_class)
  set_global_setting(:terminus_class, terminus_class)
  set_global_setting(:terminus_setting, terminus_setting)
end

Instance Attribute Details

#modelObject

Returns the value of attribute model


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# File 'lib/puppet/indirector/indirection.rb', line 13

def model
  @model
end

#nameObject

Returns the value of attribute name


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# File 'lib/puppet/indirector/indirection.rb', line 13

def name
  @name
end

#terminiObject (readonly)

Returns the value of attribute termini


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# File 'lib/puppet/indirector/indirection.rb', line 14

def termini
  @termini
end

Class Method Details

.instance(name) ⇒ Object

Find an indirection by name. This is provided so that Terminus classes can specifically hook up with the indirections they are associated with.


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# File 'lib/puppet/indirector/indirection.rb', line 20

def self.instance(name)
  @@indirections.find { |i| i.name == name }
end

.instancesObject

Return a list of all known indirections. Used to generate the reference.


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# File 'lib/puppet/indirector/indirection.rb', line 26

def self.instances
  @@indirections.collect { |i| i.name }
end

.model(name) ⇒ Object

Find an indirected model by name. This is provided so that Terminus classes can specifically hook up with the indirections they are associated with.


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# File 'lib/puppet/indirector/indirection.rb', line 32

def self.model(name)
  match = @@indirections.find { |i| i.name == name }
  return nil unless match
  match.model
end

Instance Method Details

#allow_remote_requests?Boolean


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# File 'lib/puppet/indirector/indirection.rb', line 205

def allow_remote_requests?
  terminus.allow_remote_requests?
end

#cacheObject

Create and return our cache terminus.

Raises:


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# File 'lib/puppet/indirector/indirection.rb', line 39

def cache
  raise Puppet::DevError, _("Tried to cache when no cache class was set") unless cache_class
  terminus(cache_class)
end

#cache?Boolean

Should we use a cache?


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# File 'lib/puppet/indirector/indirection.rb', line 45

def cache?
  cache_class ? true : false
end

#cache_classObject


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# File 'lib/puppet/indirector/indirection.rb', line 49

def cache_class
  @cache_class.value
end

#cache_class=(class_name) ⇒ Object

Define a terminus class to be used for caching.


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# File 'lib/puppet/indirector/indirection.rb', line 54

def cache_class=(class_name)
  validate_terminus_class(class_name) if class_name
  @cache_class.value = class_name
end

#deleteObject

This is only used for testing.


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# File 'lib/puppet/indirector/indirection.rb', line 60

def delete
  @@indirections.delete(self) if @@indirections.include?(self)
end

#destroy(key, options = {}) ⇒ Object

Remove something via the terminus.


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# File 'lib/puppet/indirector/indirection.rb', line 280

def destroy(key, options={})
  request = request(:destroy, key, nil, options)
  terminus = prepare(request)

  result = terminus.destroy(request)

  if cache? and cache.find(request(:find, key, nil, options))
    # Reuse the existing request, since it's equivalent.
    cache.destroy(request)
  end

  result
end

#docObject

Generate the full doc string.


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# File 'lib/puppet/indirector/indirection.rb', line 82

def doc
  text = ""

  text << scrub(@doc) << "\n\n" if @doc

  text << "* **Indirected Class**: `#{@indirected_class}`\n";
  if terminus_setting
    text << "* **Terminus Setting**: #{terminus_setting}\n"
  end

  text
end

#expirationObject

Calculate the expiration date for a returned instance.


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# File 'lib/puppet/indirector/indirection.rb', line 77

def expiration
  Time.now + ttl
end

#expire(key, options = {}) ⇒ Object

Expire a cached object, if one is cached. Note that we don't actually remove it, we expire it and write it back out to disk. This way people can still use the expired object if they want.


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# File 'lib/puppet/indirector/indirection.rb', line 189

def expire(key, options={})
  request = request(:expire, key, nil, options)

  return nil unless cache? && !request.ignore_cache_save?

  instance = cache.find(request(:find, key, nil, options))
  return nil unless instance

  Puppet.info _("Expiring the %{cache} cache of %{instance}") % { cache: self.name, instance: instance.name }

  # Set an expiration date in the past
  instance.expiration = Time.now - 60

  cache.save(request(:save, nil, instance, options))
end

#find(key, options = {}) ⇒ Object

Search for an instance in the appropriate terminus, caching the results if caching is configured..


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# File 'lib/puppet/indirector/indirection.rb', line 211

def find(key, options={})
  request = request(:find, key, nil, options)
  terminus = prepare(request)

  result = find_in_cache(request)
  if not result.nil?
    result
  elsif request.ignore_terminus?
    nil
  else
    # Otherwise, return the result from the terminus, caching if
    # appropriate.
    result = terminus.find(request)
    if not result.nil?
      result.expiration ||= self.expiration if result.respond_to?(:expiration)
      if cache? && !request.ignore_cache_save?
        Puppet.info _("Caching %{indirection} for %{request}") % { indirection: self.name, request: request.key }
        begin
          cache.save request(:save, key, result, options)
        rescue => detail
          Puppet.log_exception(detail)
          raise detail
        end
      end

      filtered = result
      if terminus.respond_to?(:filter)
        Puppet::Util::Profiler.profile(_("Filtered result for %{indirection} %{request}") % { indirection: self.name, request: request.key }, [:indirector, :filter, self.name, request.key]) do
          begin
            filtered = terminus.filter(result)
          rescue Puppet::Error => detail
            Puppet.log_exception(detail)
            raise detail
          end
        end
      end
      filtered
    end
  end
end

#find_in_cache(request) ⇒ Object


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# File 'lib/puppet/indirector/indirection.rb', line 263

def find_in_cache(request)
  # See if our instance is in the cache and up to date.
  cached = cache.find(request) if cache? && ! request.ignore_cache?
  return nil unless cached
  if cached.expired?
    Puppet.info _("Not using expired %{indirection} for %{request} from cache; expired at %{expiration}") % { indirection: self.name, request: request.key, expiration: cached.expiration }
    return nil
  end

  Puppet.debug "Using cached #{self.name} for #{request.key}"
  cached
rescue => detail
  Puppet.log_exception(detail, _("Cached %{indirection} for %{request} failed: %{detail}") % { indirection: self.name, request: request.key, detail: detail })
  nil
end

#head(key, options = {}) ⇒ Object

Search for an instance in the appropriate terminus, and return a boolean indicating whether the instance was found.


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# File 'lib/puppet/indirector/indirection.rb', line 254

def head(key, options={})
  request = request(:head, key, nil, options)
  terminus = prepare(request)

  # Look in the cache first, then in the terminus.  Force the result
  # to be a boolean.
  !!(find_in_cache(request) || terminus.head(request))
end

#request(*args) ⇒ Object

Set up our request object.


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# File 'lib/puppet/indirector/indirection.rb', line 131

def request(*args)
  Puppet::Indirector::Request.new(self.name, *args)
end

#reset_terminus_classObject


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# File 'lib/puppet/indirector/indirection.rb', line 165

def reset_terminus_class
  @terminus_class.value = nil
end

#save(instance, key = nil, options = {}) ⇒ Object

Save the instance in the appropriate terminus. This method is normally an instance method on the indirected class.


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# File 'lib/puppet/indirector/indirection.rb', line 312

def save(instance, key = nil, options={})
  request = request(:save, key, instance, options)
  terminus = prepare(request)

  result = terminus.save(request)

  # If caching is enabled, save our document there
  cache.save(request) if cache? && !request.ignore_cache_save?

  result
end

#search(key, options = {}) ⇒ Object

Search for more than one instance. Should always return an array.


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# File 'lib/puppet/indirector/indirection.rb', line 295

def search(key, options={})
  request = request(:search, key, nil, options)
  terminus = prepare(request)

  result = terminus.search(request)
  if result
    raise Puppet::DevError, _("Search results from terminus %{terminus_name} are not an array") % { terminus_name: terminus.name } unless result.is_a?(Array)
    result.each do |instance|
      next unless instance.respond_to? :expiration
      instance.expiration ||= self.expiration
    end
    return result
  end
end

#set_global_setting(setting, value) ⇒ Object

Use this to set indirector settings globally across threads.


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# File 'lib/puppet/indirector/indirection.rb', line 115

def set_global_setting(setting, value)
  case setting
  when :cache_class
    validate_terminus_class(value) if !value.nil?
    @cache_class = Puppet::ThreadLocal.new(value)
  when :terminus_class
    validate_terminus_class(value) if !value.nil?
    @terminus_class = Puppet::ThreadLocal.new(value)
  when :terminus_setting
    @terminus_setting = Puppet::ThreadLocal.new(value)
  else
    raise(ArgumentError, _("The setting %{setting} is not a valid indirection setting.") % {setting: setting})
  end
end

#terminus(terminus_name = nil) ⇒ Object

Return the singleton terminus for this indirection.

Raises:


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# File 'lib/puppet/indirector/indirection.rb', line 136

def terminus(terminus_name = nil)
  # Get the name of the terminus.
  raise Puppet::DevError, _("No terminus specified for %{name}; cannot redirect") % { name: self.name } unless terminus_name ||= terminus_class

  termini[terminus_name] ||= make_terminus(terminus_name)
end

#terminus_classObject

Determine the terminus class.


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# File 'lib/puppet/indirector/indirection.rb', line 153

def terminus_class
  unless @terminus_class.value
    setting = self.terminus_setting
    if setting
      self.terminus_class = Puppet.settings[setting]
    else
      raise Puppet::DevError, _("No terminus class nor terminus setting was provided for indirection %{name}") % { name: self.name}
    end
  end
  @terminus_class.value
end

#terminus_class=(klass) ⇒ Object

Specify the terminus class to use.


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# File 'lib/puppet/indirector/indirection.rb', line 170

def terminus_class=(klass)
  validate_terminus_class(klass)
  @terminus_class.value = klass
end

#terminus_settingObject

These can be used to select the terminus class.


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# File 'lib/puppet/indirector/indirection.rb', line 144

def terminus_setting
  @terminus_setting.value
end

#terminus_setting=(setting) ⇒ Object


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# File 'lib/puppet/indirector/indirection.rb', line 148

def terminus_setting=(setting)
  @terminus_setting.value = setting
end

#ttlObject

Default to the runinterval for the ttl.


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# File 'lib/puppet/indirector/indirection.rb', line 72

def ttl
  @ttl ||= Puppet[:runinterval]
end

#ttl=(value) ⇒ Object

Set the time-to-live for instances created through this indirection.

Raises:

  • (ArgumentError)

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# File 'lib/puppet/indirector/indirection.rb', line 65

def ttl=(value)
  #TRANSLATORS "TTL" stands for "time to live" and refers to a duration of time
  raise ArgumentError, _("Indirection TTL must be an integer") unless value.is_a?(Integer)
  @ttl = value
end

#validate_terminus_class(terminus_class) ⇒ Object

This is used by terminus_class= and cache=.


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# File 'lib/puppet/indirector/indirection.rb', line 176

def validate_terminus_class(terminus_class)
  unless terminus_class and terminus_class.to_s != ""
    raise ArgumentError, _("Invalid terminus name %{terminus_class}") % { terminus_class: terminus_class.inspect }
  end
  unless Puppet::Indirector::Terminus.terminus_class(self.name, terminus_class)
    raise ArgumentError, _("Could not find terminus %{terminus_class} for indirection %{name}") %
        { terminus_class: terminus_class, name: self.name }
  end
end