Included Modules

Delayed::Backend::ActiveRecord::Job

A job object that is persisted to the database. Contains the work object as a YAML field.

Public Class Methods

after_fork() click to toggle source
# File lib/delayed/backend/active_record.rb, line 23
def self.after_fork
  ::ActiveRecord::Base.establish_connection
end
before_fork() click to toggle source
# File lib/delayed/backend/active_record.rb, line 19
def self.before_fork
  ::ActiveRecord::Base.clear_all_connections!
end
clear_locks!(worker_name) click to toggle source

When a worker is exiting, make sure we don't have any locked jobs.

# File lib/delayed/backend/active_record.rb, line 28
def self.clear_locks!(worker_name)
  update_all("locked_by = null, locked_at = null", ["locked_by = ?", worker_name])
end
db_time_now() click to toggle source

Get the current time (GMT or local depending on DB) Note: This does not ping the DB to get the time, so all your clients must have syncronized clocks.

# File lib/delayed/backend/active_record.rb, line 69
def self.db_time_now
  if Time.zone
    Time.zone.now
  elsif ::ActiveRecord::Base.default_timezone == :utc
    Time.now.utc
  else
    Time.now
  end
end
find_available(worker_name, limit = 5, max_run_time = Worker.max_run_time) click to toggle source

Find a few candidate jobs to run (in case some immediately get locked by others).

# File lib/delayed/backend/active_record.rb, line 33
def self.find_available(worker_name, limit = 5, max_run_time = Worker.max_run_time)
  scope = self.ready_to_run(worker_name, max_run_time)
  scope = scope.scoped(:conditions => ['priority >= ?', Worker.min_priority]) if Worker.min_priority
  scope = scope.scoped(:conditions => ['priority <= ?', Worker.max_priority]) if Worker.max_priority

  ::ActiveRecord::Base.silence do
    scope.by_priority.all(:limit => limit)
  end
end

Public Instance Methods

lock_exclusively!(max_run_time, worker) click to toggle source

Lock this job for this worker. Returns true if we have the lock, false otherwise.

# File lib/delayed/backend/active_record.rb, line 45
def lock_exclusively!(max_run_time, worker)
  now = self.class.db_time_now
  affected_rows = if locked_by != worker
    # We don't own this job so we will update the locked_by name and the locked_at
    self.class.update_all(["locked_at = ?, locked_by = ?", now, worker], ["id = ? and (locked_at is null or locked_at < ?) and (run_at <= ?)", id, (now - max_run_time.to_i), now])
  else
    # We already own this job, this may happen if the job queue crashes.
    # Simply resume and update the locked_at
    self.class.update_all(["locked_at = ?", now], ["id = ? and locked_by = ?", id, worker])
  end
  if affected_rows == 1
    self.locked_at = now
    self.locked_by = worker
    self.locked_at_will_change!
    self.locked_by_will_change!
    return true
  else
    return false
  end
end

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