Class: Resque::Worker

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

Overview

A Resque Worker processes jobs. On platforms that support fork(2), the worker will fork off a child to process each job. This ensures a clean slate when beginning the next job and cuts down on gradual memory growth as well as low level failures.

It also ensures workers are always listening to signals from you, their master, and can react accordingly.

Constant Summary collapse

WILDCARDS =
['*', '?', '{', '}', '[', ']'].freeze
@@all_heartbeat_threads =
[]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Helpers

classify, constantize

Methods included from Logging

debug, error, fatal, info, log, warn

Constructor Details

#initialize(*queues) ⇒ Worker

Workers should be initialized with an array of string queue names. The order is important: a Worker will check the first queue given for a job. If none is found, it will check the second queue name given. If a job is found, it will be processed. Upon completion, the Worker will again check the first queue given, and so forth. In this way the queue list passed to a Worker on startup defines the priorities of queues.

If passed a single “*”, this Worker will operate on all queues in alphabetical order. Queues can be dynamically added or removed without needing to restart workers using this method.

Workers should have `#prepare` called after they are initialized if you are running work on the worker.


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# File 'lib/resque/worker.rb', line 143

def initialize(*queues)
  @shutdown = nil
  @paused = nil
  @before_first_fork_hook_ran = false

  @heartbeat_thread = nil
  @heartbeat_thread_signal = nil

  @last_state = :idle

  verbose_value = ENV['LOGGING'] || ENV['VERBOSE']
  self.verbose = verbose_value if verbose_value
  self.very_verbose = ENV['VVERBOSE'] if ENV['VVERBOSE']
  self.pre_shutdown_timeout = (ENV['RESQUE_PRE_SHUTDOWN_TIMEOUT'] || 0.0).to_f
  self.term_timeout = (ENV['RESQUE_TERM_TIMEOUT'] || 4.0).to_f
  self.term_child = ENV['TERM_CHILD']
  self.graceful_term = ENV['GRACEFUL_TERM']
  self.run_at_exit_hooks = ENV['RUN_AT_EXIT_HOOKS']

  self.queues = queues
end

Instance Attribute Details

#fork_per_job=(value) ⇒ Object (writeonly)

Sets the attribute fork_per_job

Parameters:

  • value

    the value to set the attribute fork_per_job to.


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# File 'lib/resque/worker.rb', line 65

def fork_per_job=(value)
  @fork_per_job = value
end

#graceful_termObject

should term kill workers gracefully (vs. immediately) Makes SIGTERM work like SIGQUIT


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# File 'lib/resque/worker.rb', line 59

def graceful_term
  @graceful_term
end

#hostnameObject

chomp'd hostname of this worker's machine


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# File 'lib/resque/worker.rb', line 820

def hostname
  @hostname ||= Socket.gethostname
end

#job(reload = true) ⇒ Object Also known as: processing

Returns a hash explaining the Job we're currently processing, if any.


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# File 'lib/resque/worker.rb', line 775

def job(reload = true)
  @job = nil if reload
  @job ||= decode(data_store.get_worker_payload(self)) || {}
end

#pidObject

Returns Integer PID of running worker


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# File 'lib/resque/worker.rb', line 825

def pid
  @pid ||= Process.pid
end

#pre_shutdown_timeoutObject

Returns the value of attribute pre_shutdown_timeout.


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# File 'lib/resque/worker.rb', line 50

def pre_shutdown_timeout
  @pre_shutdown_timeout
end

#run_at_exit_hooksObject

When set to true, forked workers will exit with `exit`, calling any `at_exit` code handlers that have been registered in the application. Otherwise, forked workers exit with `exit!`


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# File 'lib/resque/worker.rb', line 63

def run_at_exit_hooks
  @run_at_exit_hooks
end

#term_childObject

decide whether to use new_kill_child logic


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# File 'lib/resque/worker.rb', line 55

def term_child
  @term_child
end

#term_child_signalObject

Returns the value of attribute term_child_signal.


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# File 'lib/resque/worker.rb', line 52

def term_child_signal
  @term_child_signal
end

#term_timeoutObject

Returns the value of attribute term_timeout.


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

def term_timeout
  @term_timeout
end

#to_sObject Also known as: id

The string representation is the same as the id for this worker instance. Can be used with `Worker.find`.


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# File 'lib/resque/worker.rb', line 814

def to_s
  @to_s ||= "#{hostname}:#{pid}:#{@queues.join(',')}"
end

#verboseObject

Returns the value of attribute verbose.


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# File 'lib/resque/worker.rb', line 887

def verbose
  @verbose
end

#very_verboseObject

Returns the value of attribute very_verbose.


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# File 'lib/resque/worker.rb', line 887

def very_verbose
  @very_verbose
end

Class Method Details

.allObject

Returns an array of all worker objects.


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# File 'lib/resque/worker.rb', line 71

def self.all
  data_store.worker_ids.map { |id| find(id, :skip_exists => true) }.compact
end

.all_heartbeatsObject


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# File 'lib/resque/worker.rb', line 496

def self.all_heartbeats
  data_store.all_heartbeats
end

.all_workers_with_expired_heartbeatsObject

Returns a list of workers that have sent a heartbeat in the past, but which already expired (does NOT include workers that have never sent a heartbeat at all).


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# File 'lib/resque/worker.rb', line 502

def self.all_workers_with_expired_heartbeats
  # Use `Worker.all_heartbeats` instead of `Worker.all`
  # to prune workers which haven't been registered but have set a heartbeat.
  # https://github.com/resque/resque/pull/1751
  heartbeats = Worker.all_heartbeats
  now = data_store.server_time

  heartbeats.select do |id, heartbeat|
    if heartbeat
      seconds_since_heartbeat = (now - Time.parse(heartbeat)).to_i
      seconds_since_heartbeat > Resque.prune_interval
    else
      false
    end
  end.each_key.map do |id|
    # skip_exists must be true to include not registered workers
    find(id, :skip_exists => true)
  end
end

.attach(worker_id) ⇒ Object

Alias of `find`


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

def self.attach(worker_id)
  find(worker_id)
end

.data_storeObject


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# File 'lib/resque/worker.rb', line 33

def self.data_store
  self.redis
end

.exists?(worker_id) ⇒ Boolean

Given a string worker id, return a boolean indicating whether the worker exists

Returns:

  • (Boolean)

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# File 'lib/resque/worker.rb', line 125

def self.exists?(worker_id)
  data_store.worker_exists?(worker_id)
end

.find(worker_id, options = {}) ⇒ Object

Returns a single worker object. Accepts a string id.


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# File 'lib/resque/worker.rb', line 102

def self.find(worker_id, options = {})
  skip_exists = options[:skip_exists]

  if skip_exists || exists?(worker_id)
    host, pid, queues_raw = worker_id.split(':', 3)
    queues = queues_raw.split(',')
    worker = new(*queues)
    worker.hostname = host
    worker.to_s = worker_id
    worker.pid = pid.to_i
    worker
  else
    nil
  end
end

.kill_all_heartbeat_threadsObject


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

def self.kill_all_heartbeat_threads
  @@all_heartbeat_threads.each(&:kill).each(&:join)
  @@all_heartbeat_threads = []
end

.redisObject


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# File 'lib/resque/worker.rb', line 29

def self.redis
  Resque.redis
end

.workingObject

Returns an array of all worker objects currently processing jobs.


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# File 'lib/resque/worker.rb', line 77

def self.working
  names = all
  return [] unless names.any?

  reportedly_working = {}

  begin
    reportedly_working = data_store.workers_map(names).reject do |key, value|
      value.nil? || value.empty?
    end
  rescue Redis::Distributed::CannotDistribute
    names.each do |name|
      value = data_store.get_worker_payload(name)
      reportedly_working[name] = value unless value.nil? || value.empty?
    end
  end

  reportedly_working.keys.map do |key|
    worker = find(key.sub("worker:", ''), :skip_exists => true)
    worker.job = worker.decode(reportedly_working[key])
    worker
  end.compact
end

Instance Method Details

#==(other) ⇒ Object

Is this worker the same as another worker?


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# File 'lib/resque/worker.rb', line 804

def ==(other)
  to_s == other.to_s
end

#child_already_exited?Boolean

Returns:

  • (Boolean)

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# File 'lib/resque/worker.rb', line 568

def child_already_exited?
  Process.waitpid(@child, Process::WNOHANG)
end

#data_storeObject


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

def redis
  Resque.redis
end

#decode(object) ⇒ Object

Given a string, returns a Ruby object.


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# File 'lib/resque/worker.rb', line 44

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

#done_workingObject

Called when we are done working - clears our `working_on` state and tells Redis we processed a job.


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# File 'lib/resque/worker.rb', line 728

def done_working
  data_store.worker_done_working(self) do |**opts|
    processed!(**opts)
  end
end

#enable_gc_optimizationsObject

Enables GC Optimizations if you're running REE. www.rubyenterpriseedition.com/faq.html#adapt_apps_for_cow


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# File 'lib/resque/worker.rb', line 386

def enable_gc_optimizations
  if GC.respond_to?(:copy_on_write_friendly=)
    GC.copy_on_write_friendly = true
  end
end

#encode(object) ⇒ Object

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


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# File 'lib/resque/worker.rb', line 39

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

#failedObject

How many failed jobs has this worker seen? Returns an int.


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# File 'lib/resque/worker.rb', line 754

def failed
  Stat["failed:#{self}"]
end

#failed!Object

Tells Redis we've failed a job.


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# File 'lib/resque/worker.rb', line 759

def failed!
  Stat << "failed"
  Stat << "failed:#{self}"
end

#fork_per_job?Boolean

Returns:

  • (Boolean)

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# File 'lib/resque/worker.rb', line 792

def fork_per_job?
  return @fork_per_job if defined?(@fork_per_job)
  @fork_per_job = ENV["FORK_PER_JOB"] != 'false' && Kernel.respond_to?(:fork)
end

#glob_match(list, pattern) ⇒ Object


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# File 'lib/resque/worker.rb', line 219

def glob_match(list, pattern)
  list.select do |queue|
    File.fnmatch?(pattern, queue) &&
      @skip_queues.none? { |skip_pattern| File.fnmatch?(skip_pattern, queue) }
  end.sort
end

#heartbeatObject


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# File 'lib/resque/worker.rb', line 484

def heartbeat
  data_store.heartbeat(self)
end

#heartbeat!(time = data_store.server_time) ⇒ Object


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# File 'lib/resque/worker.rb', line 492

def heartbeat!(time = data_store.server_time)
  data_store.heartbeat!(self, time)
end

#idle?Boolean

Boolean - true if idle, false if not

Returns:

  • (Boolean)

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# File 'lib/resque/worker.rb', line 788

def idle?
  state == :idle
end

#inspectObject


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# File 'lib/resque/worker.rb', line 808

def inspect
  "#<Worker #{to_s}>"
end

#kill_background_threadsObject


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# File 'lib/resque/worker.rb', line 675

def kill_background_threads
  if @heartbeat_thread
    @heartbeat_thread_signal.signal
    @heartbeat_thread.join
  end
end

#kill_childObject

Kills the forked child immediately, without remorse. The job it is processing will not be completed.


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# File 'lib/resque/worker.rb', line 472

def kill_child
  if @child
    log_with_severity :debug, "Killing child at #{@child}"
    if `ps -o pid,state -p #{@child}`
      Process.kill("KILL", @child) rescue nil
    else
      log_with_severity :debug, "Child #{@child} not found, restarting."
      shutdown
    end
  end
end

#linux_worker_pidsObject

Find Resque worker pids on Linux and OS X.


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# File 'lib/resque/worker.rb', line 850

def linux_worker_pids
  `ps -A -o pid,command | grep -E "[r]esque:work|[r]esque:\sStarting|[r]esque-[0-9]" | grep -v "resque-web"`.split("\n").map do |line|
    line.split(' ')[0]
  end
end

#log(message) ⇒ Object


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# File 'lib/resque/worker.rb', line 878

def log(message)
  info(message)
end

#log!(message) ⇒ Object


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# File 'lib/resque/worker.rb', line 882

def log!(message)
  debug(message)
end

#new_kill_childObject

Kills the forked child immediately with minimal remorse. The job it is processing will not be completed. Send the child a TERM signal, wait <term_timeout> seconds, and then a KILL signal if it has not quit If pre_shutdown_timeout has been set to a positive number, it will allow the child that many seconds before sending the aforementioned TERM and KILL.


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# File 'lib/resque/worker.rb', line 543

def new_kill_child
  if @child
    unless child_already_exited?
      if pre_shutdown_timeout && pre_shutdown_timeout > 0.0
        log_with_severity :debug, "Waiting #{pre_shutdown_timeout.to_f}s for child process to exit"
        return if wait_for_child_exit(pre_shutdown_timeout)
      end

      log_with_severity :debug, "Sending TERM signal to child #{@child}"
      Process.kill("TERM", @child)

      if wait_for_child_exit(term_timeout)
        return
      else
        log_with_severity :debug, "Sending KILL signal to child #{@child}"
        Process.kill("KILL", @child)
      end
    else
      log_with_severity :debug, "Child #{@child} already quit."
    end
  end
rescue SystemCallError
  log_with_severity :error, "Child #{@child} already quit and reaped."
end

#pause_processingObject

Stop processing jobs after the current one has completed (if we're currently running one).


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# File 'lib/resque/worker.rb', line 587

def pause_processing
  log_with_severity :info, "USR2 received; pausing job processing"
  run_hook :before_pause, self
  @paused = true
end

#paused?Boolean

are we paused?

Returns:

  • (Boolean)

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# File 'lib/resque/worker.rb', line 581

def paused?
  @paused || redis.get('pause-all-workers').to_s.strip.downcase == 'true'
end

#perform(job) ⇒ Object

Processes a given job in the child.


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# File 'lib/resque/worker.rb', line 316

def perform(job)
  begin
    if fork_per_job?
      reconnect
      run_hook :after_fork, job
    end
    job.perform
  rescue Object => e
    report_failed_job(job,e)
  else
    log_with_severity :info, "done: #{job.inspect}"
  ensure
    yield job if block_given?
  end
end

#prepareObject

Daemonizes the worker if ENV is set and writes the process id to ENV if set. Should only be called once per worker.


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# File 'lib/resque/worker.rb', line 168

def prepare
  if ENV['BACKGROUND']
    Process.daemon(true)
  end

  if ENV['PIDFILE']
    File.open(ENV['PIDFILE'], 'w') { |f| f << pid }
  end

  self.reconnect if ENV['BACKGROUND']
end

#process(job = nil, &block) ⇒ Object

DEPRECATED. Processes a single job. If none is given, it will try to produce one. Usually run in the child.


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# File 'lib/resque/worker.rb', line 289

def process(job = nil, &block)
  return unless job ||= reserve

  job.worker = self
  working_on job
  perform(job, &block)
ensure
  done_working
end

#processedObject

How many jobs has this worker processed? Returns an int.


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# File 'lib/resque/worker.rb', line 743

def processed
  Stat["processed:#{self}"]
end

#processed!(**opts) ⇒ Object

Tell Redis we've processed a job.


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# File 'lib/resque/worker.rb', line 748

def processed!(**opts)
  Stat.incr("processed",         1, **opts)
  Stat.incr("processed:#{self}", 1, **opts)
end

#procline(string) ⇒ Object

Given a string, sets the procline ($0) and logs. Procline is always in the format of:

RESQUE_PROCLINE_PREFIXresque-VERSION: STRING

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# File 'lib/resque/worker.rb', line 873

def procline(string)
  $0 = "#{ENV['RESQUE_PROCLINE_PREFIX']}resque-#{Resque::VERSION}: #{string}"
  log_with_severity :debug, $0
end

#prune_dead_workersObject

Looks for any workers which should be running on this server and, if they're not, removes them from Redis.

This is a form of garbage collection. If a server is killed by a hard shutdown, power failure, or something else beyond our control, the Resque workers will not die gracefully and therefore will leave stale state information in Redis.

By checking the current Redis state against the actual environment, we can determine if Redis is old and clean it up a bit.


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# File 'lib/resque/worker.rb', line 610

def prune_dead_workers
  return unless data_store.acquire_pruning_dead_worker_lock(self, Resque.heartbeat_interval)

  all_workers = Worker.all

  known_workers = worker_pids
  all_workers_with_expired_heartbeats = Worker.all_workers_with_expired_heartbeats
  all_workers_with_expired_heartbeats.each do |worker|
    # If the worker hasn't sent a heartbeat, remove it from the registry.
    #
    # If the worker hasn't ever sent a heartbeat, we won't remove it since
    # the first heartbeat is sent before the worker is registred it means
    # that this is a worker that doesn't support heartbeats, e.g., another
    # client library or an older version of Resque. We won't touch these.
    log_with_severity :info, "Pruning dead worker: #{worker}"

    job_class = worker.job(false)['payload']['class'] rescue nil
    worker.unregister_worker(PruneDeadWorkerDirtyExit.new(worker.to_s, job_class))
  end

  all_workers.each do |worker|
    if all_workers_with_expired_heartbeats.include?(worker)
      next
    end

    host, pid, worker_queues_raw = worker.id.split(':')
    worker_queues = worker_queues_raw.split(",")
    unless @queues.include?("*") || (worker_queues.to_set == @queues.to_set)
      # If the worker we are trying to prune does not belong to the queues
      # we are listening to, we should not touch it.
      # Attempt to prune a worker from different queues may easily result in
      # an unknown class exception, since that worker could easily be even
      # written in different language.
      next
    end

    next unless host == hostname
    next if known_workers.include?(pid)

    log_with_severity :debug, "Pruning dead worker: #{worker}"
    worker.unregister_worker
  end
end

#queuesObject

Returns a list of queues to use when searching for a job. A splat (“*”) means you want every queue (in alpha order) - this can be useful for dynamically adding new queues.


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# File 'lib/resque/worker.rb', line 210

def queues
  if @has_dynamic_queues
    current_queues = Resque.queues
    @queues.map { |queue| glob_match(current_queues, queue) }.flatten.uniq
  else
    @queues
  end
end

#queues=(queues) ⇒ Object


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# File 'lib/resque/worker.rb', line 182

def queues=(queues)
  queues = (ENV["QUEUES"] || ENV['QUEUE']).to_s.split(',') if queues.empty?
  queues = queues.map { |queue| queue.to_s.strip }

  @skip_queues, @queues = queues.partition { |queue| queue.start_with?('!') }
  @skip_queues.map! { |queue| queue[1..-1] }

  # The behavior of `queues` is dependent on the value of `@has_dynamic_queues: if it's true, the method returns the result of filtering @queues with `glob_match`
  # if it's false, the method returns @queues directly. Since `glob_match` will cause skipped queues to be filtered out, we want to make sure it's called if we have @skip_queues.any?
  @has_dynamic_queues =
    @skip_queues.any? || WILDCARDS.any? { |char| @queues.join.include?(char) }

  validate_queues
end

#reconnectObject

Reconnect to Redis to avoid sharing a connection with the parent, retry up to 3 times with increasing delay before giving up.


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# File 'lib/resque/worker.rb', line 352

def reconnect
  tries = 0
  begin
    data_store.reconnect
  rescue Redis::BaseConnectionError
    if (tries += 1) <= 3
      log_with_severity :error, "Error reconnecting to Redis; retrying"
      sleep(tries)
      retry
    else
      log_with_severity :error, "Error reconnecting to Redis; quitting"
      raise
    end
  end
end

#redisObject


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# File 'lib/resque/worker.rb', line 24

def redis
  Resque.redis
end

#register_signal_handlersObject

Registers the various signal handlers a worker responds to.

TERM: Shutdown immediately, stop processing jobs.

INT: Shutdown immediately, stop processing jobs.

QUIT: Shutdown after the current job has finished processing. USR1: Kill the forked child immediately, continue processing jobs. USR2: Don't process any new jobs CONT: Start processing jobs again after a USR2


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# File 'lib/resque/worker.rb', line 400

def register_signal_handlers
  trap('TERM') { graceful_term ? shutdown : shutdown!  }
  trap('INT')  { shutdown!  }

  begin
    trap('QUIT') { shutdown   }
    if term_child
      trap('USR1') { new_kill_child }
    else
      trap('USR1') { kill_child }
    end
    trap('USR2') { pause_processing }
    trap('CONT') { unpause_processing }
  rescue ArgumentError
    log_with_severity :warn, "Signals QUIT, USR1, USR2, and/or CONT not supported."
  end

  log_with_severity :debug, "Registered signals"
end

#register_workerObject

Registers ourself as a worker. Useful when entering the worker lifecycle on startup.


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# File 'lib/resque/worker.rb', line 656

def register_worker
  data_store.register_worker(self)
end

#remove_heartbeatObject


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# File 'lib/resque/worker.rb', line 488

def remove_heartbeat
  data_store.remove_heartbeat(self)
end

#report_failed_job(job, exception) ⇒ Object

Reports the exception and marks the job as failed


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# File 'lib/resque/worker.rb', line 300

def report_failed_job(job,exception)
  log_with_severity :error, "#{job.inspect} failed: #{exception.inspect}"
  begin
    job.fail(exception)
  rescue Object => exception
    log_with_severity :error, "Received exception when reporting failure: #{exception.inspect}"
  end
  begin
    failed!
  rescue Object => exception
    log_with_severity :error, "Received exception when increasing failed jobs counter (redis issue) : #{exception.inspect}"
  end
end

#reserveObject

Attempts to grab a job off one of the provided queues. Returns nil if no job can be found.


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# File 'lib/resque/worker.rb', line 334

def reserve
  queues.each do |queue|
    log_with_severity :debug, "Checking #{queue}"
    if job = Resque.reserve(queue)
      log_with_severity :debug, "Found job on #{queue}"
      return job
    end
  end

  nil
rescue Exception => e
  log_with_severity :error, "Error reserving job: #{e.inspect}"
  log_with_severity :error, e.backtrace.join("\n")
  raise e
end

#run_hook(name, *args) ⇒ Object

Runs a named hook, passing along any arguments.


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# File 'lib/resque/worker.rb', line 661

def run_hook(name, *args)
  hooks = Resque.send(name)
  return if hooks.empty?
  return if name == :before_first_fork && @before_first_fork_hook_ran
  msg = "Running #{name} hooks"
  msg << " with #{args.inspect}" if args.any?
  log_with_severity :info, msg

  hooks.each do |hook|
    args.any? ? hook.call(*args) : hook.call
    @before_first_fork_hook_ran = true if name == :before_first_fork
  end
end

#shutdownObject

Schedule this worker for shutdown. Will finish processing the current job.


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# File 'lib/resque/worker.rb', line 441

def shutdown
  log_with_severity :info, 'Exiting...'
  @shutdown = true
end

#shutdown!Object

Kill the child and shutdown immediately. If not forking, abort this process.


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# File 'lib/resque/worker.rb', line 448

def shutdown!
  shutdown
  if term_child
    if fork_per_job?
      new_kill_child
    else
      # Raise TermException in the same process
      trap('TERM') do
        # ignore subsequent terms
      end
      raise TermException.new("SIGTERM")
    end
  else
    kill_child
  end
end

#shutdown?Boolean

Should this worker shutdown as soon as current job is finished?

Returns:

  • (Boolean)

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# File 'lib/resque/worker.rb', line 466

def shutdown?
  @shutdown
end

#solaris_worker_pidsObject

Find Resque worker pids on Solaris.

Returns an Array of string pids of all the other workers on this machine. Useful when pruning dead workers on startup.


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# File 'lib/resque/worker.rb', line 860

def solaris_worker_pids
  `ps -A -o pid,comm | grep "[r]uby" | grep -v "resque-web"`.split("\n").map do |line|
    real_pid = line.split(' ')[0]
    pargs_command = `pargs -a #{real_pid} 2>/dev/null | grep [r]esque | grep -v "resque-web"`
    if pargs_command.split(':')[1] == " resque-#{Resque::VERSION}"
      real_pid
    end
  end.compact
end

#start_heartbeatObject


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# File 'lib/resque/worker.rb', line 522

def start_heartbeat
  remove_heartbeat

  @heartbeat_thread_signal = Resque::ThreadSignal.new

  @heartbeat_thread = Thread.new do
    loop do
      heartbeat!
      signaled = @heartbeat_thread_signal.wait_for_signal(Resque.heartbeat_interval)
      break if signaled
    end
  end

  @@all_heartbeat_threads << @heartbeat_thread
end

#startedObject

What time did this worker start? Returns an instance of `Time`


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# File 'lib/resque/worker.rb', line 765

def started
  data_store.worker_start_time(self)
end

#started!Object

Tell Redis we've started


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# File 'lib/resque/worker.rb', line 770

def started!
  data_store.worker_started(self)
end

#startupObject

Runs all the methods needed when a worker begins its lifecycle.


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# File 'lib/resque/worker.rb', line 369

def startup
  $0 = "resque: Starting"

  enable_gc_optimizations
  register_signal_handlers
  start_heartbeat
  prune_dead_workers
  run_hook :before_first_fork
  register_worker

  # Fix buffering so we can `rake resque:work > resque.log` and
  # get output from the child in there.
  $stdout.sync = true
end

#stateObject

Returns a symbol representing the current worker state, which can be either :working or :idle


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# File 'lib/resque/worker.rb', line 799

def state
  data_store.get_worker_payload(self) ? :working : :idle
end

#state_changeObject


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# File 'lib/resque/worker.rb', line 734

def state_change
  current_state = state
  if current_state != @last_state
    run_hook :queue_empty if current_state == :idle
    @last_state = current_state
  end
end

#unpause_processingObject

Start processing jobs again after a pause


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# File 'lib/resque/worker.rb', line 594

def unpause_processing
  log_with_severity :info, "CONT received; resuming job processing"
  @paused = false
  run_hook :after_pause, self
end

#unregister_signal_handlersObject


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# File 'lib/resque/worker.rb', line 420

def unregister_signal_handlers
  trap('TERM') do
    trap('TERM') do
      # Ignore subsequent term signals
    end

    raise TermException.new("SIGTERM")
  end

  trap('INT', 'DEFAULT')

  begin
    trap('QUIT', 'DEFAULT')
    trap('USR1', 'DEFAULT')
    trap('USR2', 'DEFAULT')
  rescue ArgumentError
  end
end

#unregister_worker(exception = nil) ⇒ Object

Unregisters ourself as a worker. Useful when shutting down.


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# File 'lib/resque/worker.rb', line 683

def unregister_worker(exception = nil)
  # If we're still processing a job, make sure it gets logged as a
  # failure.
  if (hash = processing) && !hash.empty?
    job = Job.new(hash['queue'], hash['payload'])
    # Ensure the proper worker is attached to this job, even if
    # it's not the precise instance that died.
    job.worker = self
    begin
      job.fail(exception || DirtyExit.new("Job still being processed"))
    rescue RuntimeError => e
      log_with_severity :error, e.message
    end
  end

  kill_background_threads

  data_store.unregister_worker(self) do |**opts|
    Stat.clear("processed:#{self}", **opts)
    Stat.clear("failed:#{self}",    **opts)
  end
rescue Exception => exception_while_unregistering
  message = exception_while_unregistering.message
  if exception
    message += "\nOriginal Exception (#{exception.class}): #{exception.message}"
    message += "\n  #{exception.backtrace.join("  \n")}" if exception.backtrace
  end
  fail(exception_while_unregistering.class,
       message,
       exception_while_unregistering.backtrace)
end

#validate_queuesObject

A worker must be given a queue, otherwise it won't know what to do with itself.

You probably never need to call this.


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# File 'lib/resque/worker.rb', line 201

def validate_queues
  if @queues.nil? || @queues.empty?
    raise NoQueueError.new("Please give each worker at least one queue.")
  end
end

#wait_for_child_exit(timeout) ⇒ Object


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# File 'lib/resque/worker.rb', line 572

def wait_for_child_exit(timeout)
  (timeout * 10).round.times do |i|
    sleep(0.1)
    return true if child_already_exited?
  end
  false
end

#windows_worker_pidsObject

Returns an Array of string pids of all the other workers on this machine. Useful when pruning dead workers on startup.


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# File 'lib/resque/worker.rb', line 843

def windows_worker_pids
  tasklist_output = `tasklist /FI "IMAGENAME eq ruby.exe" /FO list`.encode("UTF-8", Encoding.locale_charmap)
  tasklist_output.split($/).select { |line| line =~ /^PID:/ }.collect { |line| line.gsub(/PID:\s+/, '') }
end

#work(interval = 5.0, &block) ⇒ Object

This is the main workhorse method. Called on a Worker instance, it begins the worker life cycle.

The following events occur during a worker's life cycle:

  1. Startup: Signals are registered, dead workers are pruned,

    and this worker is registered.
    
  2. Work loop: Jobs are pulled from a queue and processed.

  3. Teardown: This worker is unregistered.

Can be passed a float representing the polling frequency. The default is 5 seconds, but for a semi-active site you may want to use a smaller value.

Also accepts a block which will be passed the job as soon as it has completed processing. Useful for testing.


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# File 'lib/resque/worker.rb', line 242

def work(interval = 5.0, &block)
  interval = Float(interval)
  startup

  loop do
    break if shutdown?

    unless work_one_job(&block)
      state_change
      break if interval.zero?
      log_with_severity :debug, "Sleeping for #{interval} seconds"
      procline paused? ? "Paused" : "Waiting for #{queues.join(',')}"
      sleep interval
    end
  end

  unregister_worker
  run_hook :worker_exit
rescue Exception => exception
  return if exception.class == SystemExit && !@child && run_at_exit_hooks
  log_with_severity :error, "Failed to start worker : #{exception.inspect}"
  unregister_worker(exception)
  run_hook :worker_exit
end

#work_one_job(job = nil, &block) ⇒ Object


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

def work_one_job(job = nil, &block)
  return false if paused?
  return false unless job ||= reserve

  working_on job
  procline "Processing #{job.queue} since #{Time.now.to_i} [#{job.payload_class_name}]"

  log_with_severity :info, "got: #{job.inspect}"
  job.worker = self

  if fork_per_job?
    perform_with_fork(job, &block)
  else
    perform(job, &block)
  end

  done_working
  true
end

#worker_pidsObject

Returns an Array of string pids of all the other workers on this machine. Useful when pruning dead workers on startup.


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# File 'lib/resque/worker.rb', line 831

def worker_pids
  if RUBY_PLATFORM =~ /solaris/
    solaris_worker_pids
  elsif RUBY_PLATFORM =~ /mingw32/
    windows_worker_pids
  else
    linux_worker_pids
  end
end

#working?Boolean

Boolean - true if working, false if not

Returns:

  • (Boolean)

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# File 'lib/resque/worker.rb', line 783

def working?
  state == :working
end

#working_on(job) ⇒ Object

Given a job, tells Redis we're working on it. Useful for seeing what workers are doing and when.


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# File 'lib/resque/worker.rb', line 717

def working_on(job)
  data = encode \
    :queue   => job.queue,
    :run_at  => Time.now.utc.iso8601,
    :payload => job.payload
  data_store.set_worker_payload(self,data)
  state_change
end