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
end

Instance Method Details

#get_or_refresh_lock ⇒ Object 



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# File 'lib/sidecloq/locker.rb', line 49

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

#has_lock? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/sidecloq/locker.rb', line 35

def has_lock?
  @obtained_lock.set?
end

#start ⇒ Object 



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# File 'lib/sidecloq/locker.rb', line 41

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

#stop(timeout = nil) ⇒ Object 



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# File 'lib/sidecloq/locker.rb', line 26

def stop(timeout = nil)
  if @check_task
    logger.debug("Stopping locker check task")
    @check_task.shutdown
    @check_task.wait_for_termination(timeout)
    logger.debug("Stopped locker check task")
  end
end

#with_lock ⇒ Object

blocks until lock is obtained, then yields



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# File 'lib/sidecloq/locker.rb', line 19

def with_lock
  start
  @obtained_lock.wait
  yield
  stop
end