A job object that is persisted to the database. Contains the work object as a YAML field.
# File lib/delayed/backend/active_record.rb, line 23 def self.after_fork ::ActiveRecord::Base.establish_connection end
# File lib/delayed/backend/active_record.rb, line 19 def self.before_fork ::ActiveRecord::Base.clear_all_connections! end
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
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 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
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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