Class: MiddleManagement::Manager

Inherits:
Object
  • Object
show all
Defined in:
lib/middle_management/manager.rb

Class Method Summary collapse

Class Method Details

.calculate_needed_worker_count(num_jobs) ⇒ Object 



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# File 'lib/middle_management/manager.rb', line 56

def self.calculate_needed_worker_count(num_jobs)
  ideal_worker_count = num_jobs / MiddleManagement::Config::JOBS_PER_WORKER + 1
  ideal_worker_count -= 1 if num_jobs % MiddleManagement::Config::JOBS_PER_WORKER == 0
  [MiddleManagement::Config::MIN_WORKERS, [ideal_worker_count, MiddleManagement::Config::MAX_WORKERS].min].max
end

.current_jobs_count ⇒ Object 



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# File 'lib/middle_management/manager.rb', line 48

def self.current_jobs_count
  if @@current_jobs_count.nil? || @@current_jobs_count == 0 || self.current_jobs_count_last_queried.nil? || self.current_jobs_count_last_queried < 1.minute.ago
    self.current_jobs_count = Delayed::Backend::ActiveRecord::Job.where("run_at <= ? AND failed_at IS NULL AND locked_by IS NULL", Delayed::Backend::ActiveRecord::Job.db_time_now).count
    self.current_jobs_count_last_queried = Time.now
  end
  @@current_jobs_count
end

.enforce_number_of_current_jobs(_num_workers_last_set_at = nil, _last_enforcement_job_set_for = nil) ⇒ Object

ToDo: Figure out what to do about caching worker counts



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# File 'lib/middle_management/manager.rb', line 8

def self.enforce_number_of_current_jobs(_num_workers_last_set_at = nil, _last_enforcement_job_set_for = nil)
  self.current_worker_count = self.get_heroku_client.info(MiddleManagement::Config::HEROKU_APP)[:workers].to_i
  # Do nothing if our worker figures are up-to-date
  return if !self.num_jobs_changes_worker_count?(self.current_jobs_count)
  
  # Load cached values if they're supplied. This is to prevent different instances
  # from re-querying the heroku API.
  self.num_workers_last_set_at = _num_workers_last_set_at unless _num_workers_last_set_at.nil?
  self.last_enforcement_job_set_for = _last_enforcement_job_set_for unless _last_enforcement_job_set_for.nil?
  
  # Set number of workers if we haven't set it recently
  if self.num_workers_last_set_at.nil? || self.num_workers_last_set_at < 10.seconds.ago || self.current_worker_count.nil? || self.current_worker_count == 0
    self.set_num_workers(self.calculate_needed_worker_count(self.current_jobs_count))
    self.num_workers_last_set_at = Time.now
  else
    # Schedule job with cached data if we don't have one scheduled
    if self.last_enforcement_job_set_for.nil? || Time.now > self.last_enforcement_job_set_for # Prevent multiple jobs within our window
      self.last_enforcement_job_set_for = Time.now + 10.seconds
      self.delay(:run_at => self.last_enforcement_job_set_for).enforce_number_of_current_jobs(self.num_workers_last_set_at, self.last_enforcement_job_set_for)
      # Make sure we have at least one worker running to cover the job.
      self.set_num_workers(1) if self.current_worker_count == 0
    end
  end
end

.get_heroku_client ⇒ Object 



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# File 'lib/middle_management/manager.rb', line 72

def self.get_heroku_client
  Heroku::Client.new(MiddleManagement::Config::HEROKU_USERNAME, MiddleManagement::Config::HEROKU_PASSWORD)
end

.num_jobs_changes_worker_count?(num_jobs) ⇒ Boolean

Returns:



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# File 'lib/middle_management/manager.rb', line 62

def self.num_jobs_changes_worker_count?(num_jobs)
  return false if num_jobs.nil?
  return false if self.calculate_needed_worker_count(num_jobs) == self.current_worker_count
  return true if self.current_worker_count.nil?
  # Next two lines are verified in calculate_needed_worker_count(), but let's be safe since we're dealing with real money...
  return false if self.calculate_needed_worker_count(num_jobs) < MiddleManagement::Config::MIN_WORKERS
  return false if self.calculate_needed_worker_count(num_jobs) > MiddleManagement::Config::MAX_WORKERS
  true
end

.set_num_workers(num_workers) ⇒ Object 



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# File 'lib/middle_management/manager.rb', line 76

def self.set_num_workers(num_workers)
  self.current_worker_count = num_workers
  self.get_heroku_client.set_workers(MiddleManagement::Config::HEROKU_APP, num_workers)
end

.track_completion ⇒ Object 



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# File 'lib/middle_management/manager.rb', line 37

def self.track_completion
  self.current_jobs_count -= 1
end

.track_creation ⇒ Object 



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# File 'lib/middle_management/manager.rb', line 33

def self.track_creation
  self.current_jobs_count += 1
end