Class: Delayed::Worker

Inherits:
Object
  • Object
show all
Defined in:
lib/delayed/worker.rb

Constant Summary collapse

LINUX_PAGE_SIZE =

linux w/ proc fs

(size = `getconf PAGESIZE`.to_i; size > 0 ? size : 4096)

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Worker

Returns a new instance of Worker.



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# File 'lib/delayed/worker.rb', line 42

def initialize(options = {})
  @exit = false
  @parent_pid = options[:parent_pid]
  @queue_name = options[:queue] ||= Settings.queue
  @min_priority = options[:min_priority]
  @max_priority = options[:max_priority]
  @max_job_count = options[:worker_max_job_count].to_i
  @max_memory_usage = options[:worker_max_memory_usage].to_i
  @work_queue = options.delete(:work_queue) || WorkQueue::InProcess.new
  @config = options
  @job_count = 0

  app = Rails.application
  if app && !app.config.cache_classes
    Delayed::Worker.lifecycle.around(:perform) do |&block|
      reload = app.config.reload_classes_only_on_change != true || app.reloaders.map(&:updated?).any?
      ActionDispatch::Reloader.prepare! if reload
      begin
        block.call
      ensure
        ActionDispatch::Reloader.cleanup! if reload
      end
    end
  end

  plugins.each { |plugin| plugin.inject! }
end

Instance Attribute Details

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/delayed/worker.rb', line 9

def config
  @config
end

#max_priority ⇒ Object (readonly)

Returns the value of attribute max_priority.



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# File 'lib/delayed/worker.rb', line 9

def max_priority
  @max_priority
end

#min_priority ⇒ Object (readonly)

Returns the value of attribute min_priority.



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# File 'lib/delayed/worker.rb', line 9

def min_priority
  @min_priority
end

#queue_name ⇒ Object (readonly)

Returns the value of attribute queue_name.



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# File 'lib/delayed/worker.rb', line 9

def queue_name
  @queue_name
end

#work_queue ⇒ Object (readonly)

Returns the value of attribute work_queue.



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# File 'lib/delayed/worker.rb', line 9

def work_queue
  @work_queue
end

Class Method Details

.current_job ⇒ Object 



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# File 'lib/delayed/worker.rb', line 31

def self.current_job
  Thread.current[:running_delayed_job]
end

.lifecycle ⇒ Object 



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# File 'lib/delayed/worker.rb', line 27

def self.lifecycle
  @lifecycle ||= Delayed::Lifecycle.new
end

.on_max_failures=(block) ⇒ Object

Callback to fire when a delayed job fails max_attempts times. If this callback is defined, then the value of destroy_failed_jobs is ignored, and the job is destroyed if this block returns true.

This allows for destroying “uninteresting” failures, while keeping around interesting failures to be investigated later.

The block is called with args(job, last_exception)



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# File 'lib/delayed/worker.rb', line 19

def self.on_max_failures=(block)
  @@on_max_failures = block
end

.running_job(job) ⇒ Object 



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# File 'lib/delayed/worker.rb', line 35

def self.running_job(job)
  Thread.current[:running_delayed_job] = job
  yield
ensure
  Thread.current[:running_delayed_job] = nil
end

Instance Method Details

#configure_for_job(job) ⇒ Object

set up the session context information, so that it gets logged with the job log lines also set up a unique tmpdir, which will get removed at the end of the job.



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# File 'lib/delayed/worker.rb', line 205

def configure_for_job(job)
  previous_tmpdir = ENV['TMPDIR']

  self.class.running_job(job) do
    dir = Dir.mktmpdir("job-#{job.id}-#{self.name.gsub(/[^\w\.]/, '.')}-")
    begin
      ENV['TMPDIR'] = dir
      yield
    ensure
      FileUtils.remove_entry(dir, true)
    end
  end
ensure
  ENV['TMPDIR'] = previous_tmpdir
end

#exit? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/delayed/worker.rb', line 78

def exit?
  @exit || parent_exited?
end

#handle_failed_job(job, error) ⇒ Object 



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# File 'lib/delayed/worker.rb', line 180

def handle_failed_job(job, error)
  job.last_error = "#{error.message}\n#{error.backtrace.join("\n")}"
  say("Failed with #{error.class} [#{error.message}] (#{job.attempts} attempts)", :error)
  job.reschedule(error)
end

#id ⇒ Object 



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# File 'lib/delayed/worker.rb', line 186

def id
  Process.pid
end

#log_job(job, format = :short) ⇒ Object 



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# File 'lib/delayed/worker.rb', line 194

def log_job(job, format = :short)
  case format
  when :long
    "#{job.full_name} #{ job.to_json(:include_root => false, :only => %w(tag strand priority attempts created_at max_attempts source)) }"
  else
    job.full_name
  end
end

#name ⇒ Object 



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# File 'lib/delayed/worker.rb', line 70

def name
  @name ||= "#{Socket.gethostname rescue "X"}:#{self.id}"
end

#parent_exited? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/delayed/worker.rb', line 82

def parent_exited?
  @parent_pid && @parent_pid != Process.ppid
end

#perform(job) ⇒ Object 



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# File 'lib/delayed/worker.rb', line 140

def perform(job)
  count = 1
  raise Delayed::Backend::JobExpired, "job expired at #{job.expires_at}" if job.expired?
  self.class.lifecycle.run_callbacks(:perform, self, job) do
    set_process_name("run:#{Settings.worker_procname_prefix}#{job.id}:#{job.name}")
    say("Processing #{log_job(job, :long)}", :info)
    runtime = Benchmark.realtime do
      if job.batch?
        # each job in the batch will have perform called on it, so we don't
        # need a timeout around this
        count = perform_batch(job)
      else
        job.invoke_job
      end
      job.destroy
    end
    say("Completed #{log_job(job)} #{"%.0fms" % (runtime * 1000)}", :info)
  end
  count
rescue Exception => e
  self.class.lifecycle.run_callbacks(:error, self, job, e) do
    handle_failed_job(job, e)
  end
  count
end

#perform_batch(parent_job) ⇒ Object 



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# File 'lib/delayed/worker.rb', line 166

def perform_batch(parent_job)
  batch = parent_job.payload_object
  if batch.mode == :serial
    batch.jobs.each do |job|
      job.source = parent_job.source
      job.create_and_lock!(name)
      configure_for_job(job) do
        perform(job)
      end
    end
    batch.items.size
  end
end

#run ⇒ Object 



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# File 'lib/delayed/worker.rb', line 107

def run
  self.class.lifecycle.run_callbacks(:loop, self) do
    set_process_name("pop:#{Settings.worker_procname_prefix}#{@queue_name}:#{min_priority || 0}:#{max_priority || 'max'}")
    job = self.class.lifecycle.run_callbacks(:pop, self) do
      work_queue.get_and_lock_next_available(name, config)
    end

    if job
      configure_for_job(job) do
        @job_count += perform(job)

        if @max_job_count > 0 && @job_count >= @max_job_count
          say "Max job count of #{@max_job_count} exceeded, dying"
          @exit = true
        end

        if @max_memory_usage > 0
          memory = sample_memory
          if memory > @max_memory_usage
            say "Memory usage of #{memory} exceeds max of #{@max_memory_usage}, dying"
            @exit = true
          else
            say "Memory usage: #{memory}"
          end
        end
      end
    else
      set_process_name("wait:#{Settings.worker_procname_prefix}#{@queue_name}:#{min_priority || 0}:#{max_priority || 'max'}")
      sleep(Settings.sleep_delay + (rand * Settings.sleep_delay_stagger))
    end
  end
end

#sample_memory ⇒ Object

generic unix solution



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# File 'lib/delayed/worker.rb', line 231

def sample_memory
  s = File.read("/proc/#{Process.pid}/statm").to_i rescue 0
  s * LINUX_PAGE_SIZE / 1024
end

#say(msg, level = :debug) ⇒ Object 



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# File 'lib/delayed/worker.rb', line 190

def say(msg, level = :debug)
  Rails.logger.send(level, msg)
end

#set_process_name(new_name) ⇒ Object 



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# File 'lib/delayed/worker.rb', line 74

def set_process_name(new_name)
  $0 = "delayed:#{new_name}"
end

#start ⇒ Object 



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# File 'lib/delayed/worker.rb', line 86

def start
  say "Starting worker", :info
  set_process_name("start:#{Settings.worker_procname_prefix}#{@queue_name}:#{min_priority || 0}:#{max_priority || 'max'}")

  trap('INT') { say 'Exiting'; @exit = true }

  self.class.lifecycle.run_callbacks(:execute, self) do
    loop do
      run
      break if exit?
    end
  end

  say "Stopping worker", :info
rescue => e
  Rails.logger.fatal("Child process died: #{e.inspect}") rescue nil
  self.class.lifecycle.run_callbacks(:exceptional_exit, self, e) { }
ensure
  Delayed::Job.clear_locks!(name)
end