Class: Resque::Job

Inherits:
Object
  • Object
show all
Extended by:
Helpers
Includes:
Helpers
Defined in:
lib/resque/job.rb

Overview

A Resque::Job represents a unit of work. Each job lives on a single queue and has an associated payload object. The payload is a hash with two attributes: ‘class` and `args`. The `class` is the name of the Ruby class which should be used to run the job. The `args` are an array of arguments which should be passed to the Ruby class’s ‘perform` class-level method.

You can manually run a job using this code:

job = Resque::Job.reserve(:high)
klass = Resque::Job.constantize(job.payload['class'])
klass.perform(*job.payload['args'])

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Helpers

classify, constantize, decode, encode, redis

Constructor Details

#initialize(queue, payload) ⇒ Job

Returns a new instance of Job.



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# File 'lib/resque/job.rb', line 28

def initialize(queue, payload)
  @queue = queue
  @payload = payload
end

Instance Attribute Details

#payload ⇒ Object (readonly)

This job’s associated payload object.



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# File 'lib/resque/job.rb', line 26

def payload
  @payload
end

#queue ⇒ Object (readonly)

The name of the queue from which this job was pulled (or is to be placed)



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# File 'lib/resque/job.rb', line 23

def queue
  @queue
end

#worker ⇒ Object

The worker object which is currently processing this job.



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# File 'lib/resque/job.rb', line 19

def worker
  @worker
end

Class Method Details

.create(queue, klass, *args) ⇒ Object

Creates a job by placing it on a queue. Expects a string queue name, a string class name, and an optional array of arguments to pass to the class’ ‘perform` method.

Raises an exception if no queue or class is given.



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# File 'lib/resque/job.rb', line 38

def self.create(queue, klass, *args)
  if !queue
    raise NoQueueError.new("Jobs must be placed onto a queue.")
  end

  if klass.to_s.empty?
    raise NoClassError.new("Jobs must be given a class.")
  end

  Resque.push(queue, :class => klass.to_s, :args => args)
end

.destroy(queue, klass, *args) ⇒ Object

Removes a job from a queue. Expects a string queue name, a string class name, and, optionally, args.

Returns the number of jobs destroyed.

If no args are provided, it will remove all jobs of the class provided.

That is, for these two jobs:

{ ‘class’ => ‘UpdateGraph’, ‘args’ => [‘defunkt’] } { ‘class’ => ‘UpdateGraph’, ‘args’ => [‘mojombo’] }

The following call will remove both:

Resque::Job.destroy(queue, 'UpdateGraph')

Whereas specifying args will only remove the 2nd job:

Resque::Job.destroy(queue, 'UpdateGraph', 'mojombo')

This method can be potentially very slow and memory intensive, depending on the size of your queue, as it loads all jobs into a Ruby array before processing.



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# File 'lib/resque/job.rb', line 74

def self.destroy(queue, klass, *args)
  klass = klass.to_s
  queue = "queue:#{queue}"
  destroyed = 0

  redis.lrange(queue, 0, -1).each do |string|
    json   = decode(string)

    match  = json['class'] == klass
    match &= json['args'] == args unless args.empty?

    if match
      destroyed += redis.lrem(queue, 0, string).to_i
    end
  end

  destroyed
end

.reserve(queue) ⇒ Object

Given a string queue name, returns an instance of Resque::Job if any jobs are available. If not, returns nil.



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# File 'lib/resque/job.rb', line 95

def self.reserve(queue)
  return unless payload = Resque.pop(queue)
  new(queue, payload)
end

Instance Method Details

#==(other) ⇒ Object

Equality



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# File 'lib/resque/job.rb', line 140

def ==(other)
  queue == other.queue &&
    payload_class == other.payload_class &&
    args == other.args
end

#args ⇒ Object

Returns an array of args represented in this job’s payload.



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# File 'lib/resque/job.rb', line 113

def args
  @payload['args']
end

#fail(exception) ⇒ Object

Given an exception object, hands off the needed parameters to the Failure module.



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# File 'lib/resque/job.rb', line 119

def fail(exception)
  Failure.create \
    :payload   => payload,
    :exception => exception,
    :worker    => worker,
    :queue     => queue
end

#inspect ⇒ Object

String representation



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# File 'lib/resque/job.rb', line 134

def inspect
  obj = @payload
  "(Job{%s} | %s | %s)" % [ @queue, obj['class'], obj['args'].inspect ]
end

#payload_class ⇒ Object

Returns the actual class constant represented in this job’s payload.



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# File 'lib/resque/job.rb', line 108

def payload_class
  @payload_class ||= constantize(@payload['class'])
end

#perform ⇒ Object

Attempts to perform the work represented by this job instance. Calls #perform on the class given in the payload with the arguments given in the payload.



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# File 'lib/resque/job.rb', line 103

def perform
  args ? payload_class.perform(*args) : payload_class.perform
end

#recreate ⇒ Object

Creates an identical job, essentially placing this job back on the queue.



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# File 'lib/resque/job.rb', line 129

def recreate
  self.class.create(queue, payload_class, *args)
end