gitlab-org--gitlab-foss/lib/gitlab/exclusive_lease_helpers.rb
2018-11-27 17:55:20 +01:00

33 lines
1.1 KiB
Ruby

# frozen_string_literal: true
module Gitlab
# This module provides helper methods which are intregrated with GitLab::ExclusiveLease
module ExclusiveLeaseHelpers
FailedToObtainLockError = Class.new(StandardError)
##
# This helper method blocks a process/thread until the other process cancel the obrainted lease key.
#
# Note: It's basically discouraged to use this method in the unicorn's thread,
# because it holds the connection until all `retries` is consumed.
# This could potentially eat up all connection pools.
def in_lock(key, ttl: 1.minute, retries: 10, sleep_sec: 0.01.seconds)
raise ArgumentError, 'Key needs to be specified' unless key
lease = Gitlab::ExclusiveLease.new(key, timeout: ttl)
until uuid = lease.try_obtain
# Keep trying until we obtain the lease. To prevent hammering Redis too
# much we'll wait for a bit.
sleep(sleep_sec)
break if (retries -= 1) < 0
end
raise FailedToObtainLockError, 'Failed to obtain a lock' unless uuid
yield
ensure
Gitlab::ExclusiveLease.cancel(key, uuid)
end
end
end