29106ebc4b
Consider a scenario where two jobs are concurrently accessing a job with a lock mechanism. If the second job accesses lock_manager.locked? before the first job called lock_manager.lock(lock_key), it would return a false positive. At this point, both jobs can be executed freely. To address this issue, the following change ensures that only the current thread that has set the lock can execute. Otherwise, a LockAcquisitionError will be thrown. Co-authored-by: Sojan Jose <sojan@pepalo.com> Co-authored-by: Shivam Mishra <scm.mymail@gmail.com>
34 lines
1.4 KiB
Ruby
34 lines
1.4 KiB
Ruby
# MutexApplicationJob serves as a base class for jobs that require distributed locking mechanisms.
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# It abstracts the locking logic using Redis and ensures that a block of code can be executed with
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# mutual exclusion.
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#
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# The primary mechanism provided is the `with_lock` method, which accepts a key format and associated
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# arguments. This method attempts to acquire a lock using the generated key, and if successful, it
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# executes the provided block of code. If the lock cannot be acquired, it raises a LockAcquisitionError.
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#
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# To use this class, inherit from MutexApplicationJob and make use of the `with_lock` method in the
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# `perform` method of the derived job class.
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#
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# Also see, retry mechanism here: https://edgeapi.rubyonrails.org/classes/ActiveJob/Exceptions/ClassMethods.html#method-i-retry_on
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#
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class MutexApplicationJob < ApplicationJob
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class LockAcquisitionError < StandardError; end
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def with_lock(key_format, *args)
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lock_key = format(key_format, *args)
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lock_manager = Redis::LockManager.new
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begin
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if lock_manager.lock(lock_key)
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Rails.logger.info "[#{self.class.name}] Acquired lock for: #{lock_key} on attempt #{executions}"
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yield
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else
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Rails.logger.warn "[#{self.class.name}] Failed to acquire lock on attempt #{executions}: #{lock_key}"
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raise LockAcquisitionError, "Failed to acquire lock for key: #{lock_key}"
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end
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ensure
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lock_manager.unlock(lock_key)
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end
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end
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end
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