Class: Sidecloq::Locker

Inherits:
Object
  • Object
show all
Includes:
Utils
Defined in:
lib/sidecloq/locker.rb

Overview

Locker obtains or waits for an exclusive lock on a key in redis

Constant Summary collapse

DEFAULT_LOCK_KEY = 
'sidecloq_leader_lock'

Instance Method Summary collapse

Methods included from Utils

included, #logger, #redis, #will_never_run

Constructor Details

#initialize(options = {}) ⇒ Locker

Returns a new instance of Locker.



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# File 'lib/sidecloq/locker.rb', line 8

def initialize(options = {})
  # we keep a connection from the pool by default
  @redis = options[:redis] || Sidekiq.redis_pool.checkout
  @key = options[:lock_key] || DEFAULT_LOCK_KEY
  @ttl = options[:ttl] || 60
  @check_interval = options[:check_interval] || 15
  @lock_manager = Redlock::Client.new([@redis])
  @obtained_lock = Concurrent::Event.new
  @lock = nil
end

Instance Method Details

#locked? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sidecloq/locker.rb', line 36

def locked?
  @obtained_lock.set?
end

#start ⇒ Object 



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# File 'lib/sidecloq/locker.rb', line 42

def start
  logger.debug('Starting locker check task')
  @check_task = Concurrent::TimerTask.new(
    execution_interval: @check_interval,
    run_now: true
  ) do
    try_to_get_or_refresh_lock
  end
  @check_task.execute
end

#stop(timeout = nil) ⇒ Object 



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# File 'lib/sidecloq/locker.rb', line 27

def stop(timeout = nil)
  return unless @check_task

  logger.debug('Stopping locker check task')
  @check_task.shutdown
  @check_task.wait_for_termination(timeout)
  logger.debug('Stopped locker check task')
end

#try_to_get_or_refresh_lock ⇒ Object 



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# File 'lib/sidecloq/locker.rb', line 53

def try_to_get_or_refresh_lock
  # redlock is in ms, not seconds
  if @lock
    @lock = @lock_manager.lock(@key, @ttl * 1000, extend: @lock)
  else
    @lock = @lock_manager.lock(@key, @ttl * 1000)
  end
  @obtained_lock.set if @lock
  logger.debug("Leader lock #{'not ' unless @lock}held")
  @lock
end

#with_lock ⇒ Object

blocks until lock is obtained, then yields



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# File 'lib/sidecloq/locker.rb', line 20

def with_lock
  start
  @obtained_lock.wait
  yield
  stop
end