debian-mirror-gitlab/app/services/concerns/exclusive_lease_guard.rb

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# frozen_string_literal: true
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#
# Concern that helps with getting an exclusive lease for running a block
# of code.
#
# `#try_obtain_lease` takes a block which will be run if it was able to
# obtain the lease. Implement `#lease_timeout` to configure the timeout
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# for the exclusive lease.
#
# Optionally override `#lease_key` to set the
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# lease key, it defaults to the class name with underscores.
#
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# Optionally override `#lease_release?` to prevent the job to
# be re-executed more often than LEASE_TIMEOUT.
#
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module ExclusiveLeaseGuard
extend ActiveSupport::Concern
def try_obtain_lease
lease = exclusive_lease.try_obtain
unless lease
log_error('Cannot obtain an exclusive lease. There must be another instance already in execution.')
return
end
begin
yield lease
ensure
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release_lease(lease) if lease_release?
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end
end
def exclusive_lease
@lease ||= Gitlab::ExclusiveLease.new(lease_key, timeout: lease_timeout)
end
def lease_key
@lease_key ||= self.class.name.underscore
end
def lease_timeout
raise NotImplementedError,
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"#{self.class.name} does not implement #{__method__}"
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end
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def lease_release?
true
end
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def release_lease(uuid)
Gitlab::ExclusiveLease.cancel(lease_key, uuid)
end
def renew_lease!
exclusive_lease.renew
end
def log_error(message, extra_args = {})
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Rails.logger.error(message)
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end
end