Class: Puppet::Indirector::Queue

Inherits:
Terminus show all
Extended by:
Util::Queue
Includes:
Util
Defined in:
lib/vendor/puppet/indirector/queue.rb

Overview

Implements the :queue abstract indirector terminus type, for storing model instances to a message queue, presumably for the purpose of out-of-process handling of changes related to the model.

Relies upon Puppet::Util::Queue for registry and client object management, and specifies a default queue type of :stomp, appropriate for use with a variety of message brokers.

It’s up to the queue client type to instantiate itself correctly based on Puppet configuration information.

A single queue client is maintained for the abstract terminus, meaning that you can only use one type of queue client, one message broker solution, etc., with the indirection mechanism.

Per-indirection queues are assumed, based on the indirection name. If the :catalog indirection makes use of this :queue terminus, queue operations work against the “catalog” queue. It is up to the queue client library to handle queue creation as necessary (for a number of popular queuing solutions, queue creation is automatic and not a concern).

Direct Known Subclasses

Resource::Catalog::Queue

Constant Summary

Constants included from Util

Util::AbsolutePathPosix, Util::AbsolutePathWindows

Constants included from Util::Docs

Util::Docs::HEADER_LEVELS

Instance Attribute Summary

Attributes included from Util::Docs

#doc, #nodoc

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Util::Queue

client_class, queue_type_from_class, queue_type_to_class, register_queue_type

Methods included from Util::InstanceLoader

#instance_docs, #instance_hash, #instance_load, #instance_loader, #instance_loading?, #loaded_instance, #loaded_instances

Methods included from Util

absolute_path?, activerecord_version, benchmark, binread, chuser, classproxy, #execfail, #execpipe, execute, execute_posix, execute_windows, logmethods, memory, path_to_uri, proxy, replace_file, safe_posix_fork, symbolize, symbolizehash, symbolizehash!, synchronize_on, thinmark, #threadlock, uri_to_path, wait_for_output, which, withumask

Methods included from Util::POSIX

#get_posix_field, #gid, #idfield, #methodbyid, #methodbyname, #search_posix_field, #uid

Methods inherited from Terminus

abstract_terminus?, const2name, #indirection, indirection_name, inherited, mark_as_abstract_terminus, #model, model, #name, name2const, register_terminus_class, terminus_class, terminus_classes, #terminus_type

Methods included from Util::Docs

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

Constructor Details

#initialize(*args) ⇒ Queue

Returns a new instance of Queue.

Raises:

  • (ArgumentError) 


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# File 'lib/vendor/puppet/indirector/queue.rb', line 25

def initialize(*args)
  super
  raise ArgumentError, "Queueing requires pson support" unless Puppet.features.pson?
end

Class Method Details

.intern(message) ⇒ Object

converts the message from deserialized format to an actual model instance.



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

def self.intern(message)
  result = nil
  benchmark :info, "Loaded queued #{indirection.name}" do
    result = model.convert_from(:pson, message)
  end
  result
end

.queue ⇒ Object 



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# File 'lib/vendor/puppet/indirector/queue.rb', line 46

def self.queue
  indirection_name
end

.subscribe ⇒ Object

Provides queue subscription functionality; for a given indirection, use this method on the terminus to subscribe to the indirection-specific queue. Your block will be executed per new indirection model received from the queue, with obj being the model instance.



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# File 'lib/vendor/puppet/indirector/queue.rb', line 71

def self.subscribe
  client.subscribe(queue) do |msg|
    begin
      yield(self.intern(msg))
    rescue => detail
      puts detail.backtrace if Puppet[:trace]
      Puppet.err "Error occured with subscription to queue #{queue} for indirection #{indirection_name}: #{detail}"
    end
  end
end

Instance Method Details

#client ⇒ Object

Returns the singleton queue client object.



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# File 'lib/vendor/puppet/indirector/queue.rb', line 55

def client
  self.class.client
end

#find(request) ⇒ Object

Queue has no idiomatic “find”



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# File 'lib/vendor/puppet/indirector/queue.rb', line 31

def find(request)
  nil
end

#queue ⇒ Object 



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# File 'lib/vendor/puppet/indirector/queue.rb', line 50

def queue
  self.class.queue
end

#save(request) ⇒ Object

Place the request on the queue



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# File 'lib/vendor/puppet/indirector/queue.rb', line 36

def save(request)
    result = nil
    benchmark :info, "Queued #{indirection.name} for #{request.key}" do
      result = client.publish_message(queue, request.instance.render(:pson))
    end
    result
rescue => detail
    raise Puppet::Error, "Could not write #{request.key} to queue: #{detail}\nInstance::#{request.instance}\n client : #{client}"
end