gitlab-org--gitlab-foss/app/workers/background_migration_worker.rb

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class BackgroundMigrationWorker
include ApplicationWorker
# The minimum amount of time between processing two jobs of the same migration
# class.
#
# This interval is set to 5 minutes so autovacuuming and other maintenance
# related tasks have plenty of time to clean up after a migration has been
# performed.
MIN_INTERVAL = 5.minutes.to_i
# Performs the background migration.
#
# See Gitlab::BackgroundMigration.perform for more information.
#
# class_name - The class name of the background migration to run.
# arguments - The arguments to pass to the migration class.
def perform(class_name, arguments = [])
should_perform, ttl = perform_and_ttl(class_name)
if should_perform
Gitlab::BackgroundMigration.perform(class_name, arguments)
else
# If the lease could not be obtained this means either another process is
# running a migration of this class or we ran one recently. In this case
# we'll reschedule the job in such a way that it is picked up again around
# the time the lease expires.
self.class.perform_in(ttl || MIN_INTERVAL, class_name, arguments)
end
end
def perform_and_ttl(class_name)
if always_perform?
# In test environments `perform_in` will run right away. This can then
# lead to stack level errors in the above `#perform`. To work around this
# we'll just perform the migration right away in the test environment.
[true, nil]
else
lease = lease_for(class_name)
[lease.try_obtain, lease.ttl]
end
end
def lease_for(class_name)
Gitlab::ExclusiveLease
.new("#{self.class.name}:#{class_name}", timeout: MIN_INTERVAL)
end
def always_perform?
Rails.env.test?
end
end