Class: Gitlab::JobWaiter
- Inherits:
-
Object
- Object
- Gitlab::JobWaiter
- Defined in:
- lib/gitlab/job_waiter.rb
Overview
JobWaiter can be used to wait for a number of Sidekiq jobs to complete.
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.
Constant Summary collapse
- KEY_PREFIX =
"gitlab:job_waiter"
- STARTED_METRIC =
:gitlab_job_waiter_started_total
- TIMEOUTS_METRIC =
:gitlab_job_waiter_timeouts_total
- DEFAULT_TTL =
This TTL needs to be long enough to allow whichever Sidekiq job calls JobWaiter#wait to reach BLPOP.
6.hours.to_i
Instance Attribute Summary collapse
-
#finished ⇒ Object
readonly
Returns the value of attribute finished.
-
#jobs_remaining ⇒ Object
Returns the value of attribute jobs_remaining.
-
#key ⇒ Object
readonly
Returns the value of attribute key.
-
#worker_label ⇒ Object
readonly
Returns the value of attribute worker_label.
Class Method Summary collapse
- .delete_key(key) ⇒ Object
- .generate_key ⇒ Object
- .key?(key) ⇒ Boolean
- .notify(key, jid, ttl: DEFAULT_TTL) ⇒ Object
Instance Method Summary collapse
-
#initialize(jobs_remaining = 0, key = "#{KEY_PREFIX}:#{SecureRandom.uuid}", worker_label: nil) ⇒ JobWaiter
constructor
jobs_remaining - the number of jobs left to wait for key - The key of this waiter.
-
#wait(timeout = 10) ⇒ Object
Waits for all the jobs to be completed.
Constructor Details
#initialize(jobs_remaining = 0, key = "#{KEY_PREFIX}:#{SecureRandom.uuid}", worker_label: nil) ⇒ JobWaiter
jobs_remaining - the number of jobs left to wait for key - The key of this waiter.
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# File 'lib/gitlab/job_waiter.rb', line 56 def initialize(jobs_remaining = 0, key = "#{KEY_PREFIX}:#{SecureRandom.uuid}", worker_label: nil) @key = key @jobs_remaining = jobs_remaining @finished = [] @worker_label = worker_label end |
Instance Attribute Details
#finished ⇒ Object (readonly)
Returns the value of attribute finished.
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# File 'lib/gitlab/job_waiter.rb', line 51 def finished @finished end |
#jobs_remaining ⇒ Object
Returns the value of attribute jobs_remaining.
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# File 'lib/gitlab/job_waiter.rb', line 52 def jobs_remaining @jobs_remaining end |
#key ⇒ Object (readonly)
Returns the value of attribute key.
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# File 'lib/gitlab/job_waiter.rb', line 51 def key @key end |
#worker_label ⇒ Object (readonly)
Returns the value of attribute worker_label.
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# File 'lib/gitlab/job_waiter.rb', line 51 def worker_label @worker_label end |
Class Method Details
.delete_key(key) ⇒ Object
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# File 'lib/gitlab/job_waiter.rb', line 47 def self.delete_key(key) Gitlab::Redis::SharedState.with { |redis| redis.del(key) } if key?(key) end |
.generate_key ⇒ Object
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# File 'lib/gitlab/job_waiter.rb', line 43 def self.generate_key "#{KEY_PREFIX}:#{SecureRandom.uuid}" end |
.key?(key) ⇒ Boolean
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# File 'lib/gitlab/job_waiter.rb', line 39 def self.key?(key) key.is_a?(String) && key =~ /\A#{KEY_PREFIX}:\h{8}-\h{4}-\h{4}-\h{4}-\h{12}\z/o end |
.notify(key, jid, ttl: DEFAULT_TTL) ⇒ Object
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# File 'lib/gitlab/job_waiter.rb', line 29 def self.notify(key, jid, ttl: DEFAULT_TTL) Gitlab::Redis::SharedState.with do |redis| # Use a Redis MULTI transaction to ensure we always set an expiry redis.multi do |multi| multi.lpush(key, jid) multi.expire(key, ttl) end end end |
Instance Method Details
#wait(timeout = 10) ⇒ Object
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.
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# File 'lib/gitlab/job_waiter.rb', line 68 def wait(timeout = 10) deadline = Time.now.utc + timeout increment_counter(STARTED_METRIC) Gitlab::Redis::SharedState.with do |redis| 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 # Redis interprets 0 as "wait forever", so skip the final `blpop` call break if seconds_left <= 0 list, jid = redis.blpop(key, timeout: seconds_left) # timed out unless list && jid increment_counter(TIMEOUTS_METRIC) break end @finished << jid @jobs_remaining -= 1 end end finished end |