debian-mirror-gitlab/lib/gitlab/job_waiter.rb

75 lines
2.4 KiB
Ruby
Raw Normal View History

2017-08-17 22:00:37 +05:30
module Gitlab
# JobWaiter can be used to wait for a number of Sidekiq jobs to complete.
2018-03-17 18:26:18 +05:30
#
# Its use requires the cooperation of the sidekiq jobs themselves. Set up the
# waiter, then start the jobs, passing them its `key`. Their `perform` methods
# should look like:
#
# def perform(args, notify_key)
# # do work
# ensure
# ::Gitlab::JobWaiter.notify(notify_key, jid)
# end
#
# The JobWaiter blocks popping items from a Redis array. All the sidekiq jobs
# push to that array when done. Once the waiter has popped `count` items, it
# knows all the jobs are done.
2017-08-17 22:00:37 +05:30
class JobWaiter
2018-03-27 19:54:05 +05:30
KEY_PREFIX = "gitlab:job_waiter".freeze
2018-03-17 18:26:18 +05:30
def self.notify(key, jid)
Gitlab::Redis::SharedState.with { |redis| redis.lpush(key, jid) }
end
2018-03-27 19:54:05 +05:30
def self.key?(key)
key.is_a?(String) && key =~ /\A#{KEY_PREFIX}:\h{8}-\h{4}-\h{4}-\h{4}-\h{12}\z/
end
2018-03-17 18:26:18 +05:30
attr_reader :key, :finished
attr_accessor :jobs_remaining
2017-08-17 22:00:37 +05:30
2018-03-17 18:26:18 +05:30
# jobs_remaining - the number of jobs left to wait for
# key - The key of this waiter.
2018-03-27 19:54:05 +05:30
def initialize(jobs_remaining = 0, key = "#{KEY_PREFIX}:#{SecureRandom.uuid}")
2018-03-17 18:26:18 +05:30
@key = key
@jobs_remaining = jobs_remaining
@finished = []
2017-08-17 22:00:37 +05:30
end
# Waits for all the jobs to be completed.
#
# timeout - The maximum amount of seconds to block the caller for. This
# ensures we don't indefinitely block a caller in case a job takes
# long to process, or is never processed.
2017-09-10 17:25:29 +05:30
def wait(timeout = 10)
2018-03-17 18:26:18 +05:30
deadline = Time.now.utc + timeout
Gitlab::Redis::SharedState.with do |redis|
# Fallback key expiry: allow a long grace period to reduce the chance of
# a job pushing to an expired key and recreating it
redis.expire(key, [timeout * 2, 10.minutes.to_i].max)
while jobs_remaining > 0
# Redis will not take fractional seconds. Prefer waiting too long over
# not waiting long enough
seconds_left = (deadline - Time.now.utc).ceil
2017-08-17 22:00:37 +05:30
2018-03-17 18:26:18 +05:30
# Redis interprets 0 as "wait forever", so skip the final `blpop` call
break if seconds_left <= 0
2017-08-17 22:00:37 +05:30
2018-03-17 18:26:18 +05:30
list, jid = redis.blpop(key, timeout: seconds_left)
break unless list && jid # timed out
@finished << jid
@jobs_remaining -= 1
end
# All jobs have finished, so expire the key immediately
redis.expire(key, 0) if jobs_remaining == 0
2017-08-17 22:00:37 +05:30
end
2018-03-17 18:26:18 +05:30
finished
2017-08-17 22:00:37 +05:30
end
end
end