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'])

Constant Summary collapse

DontPerform =

Raise Resque::Job::DontPerform from a before_perform hook to abort the job.

Class.new(StandardError)

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(queue, payload) ⇒ Job

Returns a new instance of Job.



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# File 'lib/resque/job.rb', line 76

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

Instance Attribute Details

#payload ⇒ Object (readonly)

This job's associated payload object.



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

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 71

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 67

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 87

def self.create(queue, klass, *args)
  Resque.validate(klass, queue)

  if Resque.inline?
    # Instantiating a Resque::Job and calling perform on it so callbacks run
    # decode(encode(args)) to ensure that args are normalized in the same manner as a non-inline job
    new(:inline, {'class' => klass, 'args' => decode(encode(args))}).perform
  else
    Resque.push(queue, :class => klass.to_s, :args => args)
  end
end

.data_store ⇒ Object 



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

def self.data_store
  self.redis
end

.decode(object) ⇒ Object

Given a string, returns a Ruby object.



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# File 'lib/resque/job.rb', line 48

def self.decode(object)
  Resque.decode(object)
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 123

def self.destroy(queue, klass, *args)
  klass = klass.to_s
  destroyed = 0

  if args.empty?
    data_store.everything_in_queue(queue).each do |string|
      if decode(string)['class'] == klass
        destroyed += data_store.remove_from_queue(queue,string).to_i
      end
    end
  else
    destroyed += data_store.remove_from_queue(queue, encode(:class => klass, :args => args))
  end

  destroyed
end

.encode(object) ⇒ Object

Given a Ruby object, returns a string suitable for storage in a queue.



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# File 'lib/resque/job.rb', line 43

def self.encode(object)
  Resque.encode(object)
end

.redis ⇒ Object 



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# File 'lib/resque/job.rb', line 22

def self.redis
  Resque.redis
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 142

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 261

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

#after_hooks ⇒ Object 



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# File 'lib/resque/job.rb', line 275

def after_hooks
  @after_hooks ||= Plugin.after_hooks(payload_class)
end

#always_hooks ⇒ Object 



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# File 'lib/resque/job.rb', line 283

def always_hooks
  @always_hooks ||= Plugin.always_hooks(payload_class)
end

#args ⇒ Object

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



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# File 'lib/resque/job.rb', line 228

def args
  @payload['args']
end

#around_hooks ⇒ Object 



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# File 'lib/resque/job.rb', line 271

def around_hooks
  @around_hooks ||= Plugin.around_hooks(payload_class)
end

#before_hooks ⇒ Object 



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# File 'lib/resque/job.rb', line 267

def before_hooks
  @before_hooks ||= Plugin.before_hooks(payload_class)
end

#classify(dashed_word) ⇒ Object

Given a word with dashes, returns a camel cased version of it.



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# File 'lib/resque/job.rb', line 53

def classify(dashed_word)
  Resque.classify(dashed_word)
end

#constantize(camel_cased_word) ⇒ Object

Tries to find a constant with the name specified in the argument string



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# File 'lib/resque/job.rb', line 58

def constantize(camel_cased_word)
  Resque.constantize(camel_cased_word)
end

#data_store ⇒ Object 



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# File 'lib/resque/job.rb', line 20

def redis
  Resque.redis
end

#decode(object) ⇒ Object

Given a string, returns a Ruby object.



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# File 'lib/resque/job.rb', line 37

def decode(object)
  Resque.decode(object)
end

#encode(object) ⇒ Object

Given a Ruby object, returns a string suitable for storage in a queue.



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# File 'lib/resque/job.rb', line 32

def encode(object)
  Resque.encode(object)
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 234

def fail(exception)
  begin
    run_failure_hooks(exception)
  rescue Exception => e
    raise e
  ensure
    Failure.create \
      :payload   => payload,
      :exception => exception,
      :worker    => worker,
      :queue     => queue
  end
end

#failure_hooks ⇒ Object 



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# File 'lib/resque/job.rb', line 279

def failure_hooks
  @failure_hooks ||= Plugin.failure_hooks(payload_class)
end

#has_payload_class? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/resque/job.rb', line 221

def has_payload_class?
  payload_class != Object
rescue NameError
  false
end

#inspect ⇒ Object

String representation



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# File 'lib/resque/job.rb', line 255

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 210

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

#payload_class_name ⇒ Object

Returns the payload class as a string without raising NameError



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# File 'lib/resque/job.rb', line 215

def payload_class_name
  payload_class.to_s
rescue NameError
  'No Name'
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 150

def perform
  job = payload_class
  job_args = args || []
  job_was_performed = false

  begin
    # Execute before_perform hook. Abort the job gracefully if
    # Resque::Job::DontPerform is raised.
    begin
      before_hooks.each do |hook|
        job.send(hook, *job_args)
      end
    rescue DontPerform
      return false
    end

    # Execute the job. Do it in an around_perform hook if available.
    if around_hooks.empty?
      job.perform(*job_args)
      job_was_performed = true
    else
      # We want to nest all around_perform plugins, with the last one
      # finally calling perform
      stack = around_hooks.reverse.inject(nil) do |last_hook, hook|
        if last_hook
          lambda do
            job.send(hook, *job_args) { last_hook.call }
          end
        else
          lambda do
            job.send(hook, *job_args) do
              result = job.perform(*job_args)
              job_was_performed = true
              result
            end
          end
        end
      end
      stack.call
    end

    # Execute after_perform hook
    after_hooks.each do |hook|
      job.send(hook, *job_args)
    end

    # Return true if the job was performed
    return job_was_performed

  # If an exception occurs during the job execution, look for an
  # on_failure hook then re-raise.
  rescue Object => e
    run_failure_hooks(e)
    raise e
  ensure
    run_always_hooks($!)
  end
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 250

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

#redis ⇒ Object 



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# File 'lib/resque/job.rb', line 17

def redis
  Resque.redis
end

#run_always_hooks(job_failure = nil) ⇒ Object 



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# File 'lib/resque/job.rb', line 302

def run_always_hooks(job_failure = nil)
  job_args = args || []
  always_hooks.each { |hook| payload_class.send(hook, *job_args) } if has_payload_class?
rescue Exception => e
  if job_failure
    error_message = "Additional error (#{e.class}: #{e}) occurred in running always hooks for job #{inspect}\n" \
      "Original error that caused job failure was #{e.class}: #{job_failure.class}: #{job_failure.message}"
    raise RuntimeError.new(error_message)
  end
  raise e
end

#run_failure_hooks(exception) ⇒ Object 



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# File 'lib/resque/job.rb', line 287

def run_failure_hooks(exception)
  begin
    job_args = args || []
    if has_payload_class?
      failure_hooks.each { |hook| payload_class.send(hook, exception, *job_args) } unless @failure_hooks_ran
    end
  rescue Exception => e
    error_message = "Additional error (#{e.class}: #{e}) occurred in running failure hooks for job #{inspect}\n" \
                    "Original error that caused job failure was #{e.class}: #{exception.class}: #{exception.message}"
    raise RuntimeError.new(error_message)
  ensure
    @failure_hooks_ran = true
  end
end