Class: Hyrax::LockManager

Inherits:
Object
  • Object
show all
Defined in:
app/services/hyrax/lock_manager.rb

Defined Under Namespace

Classes: UnableToAcquireLockError

Instance Method Summary collapse

Constructor Details

#initialize(time_to_live, retry_count, retry_delay) ⇒ LockManager

Returns a new instance of LockManager.

Parameters:

  • time_to_live (Fixnum) —

    How long to hold the lock in milliseconds

  • retry_count (Fixnum) —

    How many times to retry to acquire the lock before raising UnableToAcquireLockError

  • retry_delay (Fixnum) —

    Maximum wait time in milliseconds before retrying. Wait time is a random value between 0 and retry_delay.



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# File 'app/services/hyrax/lock_manager.rb', line 11

def initialize(time_to_live, retry_count, retry_delay)
  @ttl = time_to_live
  @retry_count = retry_count
  @retry_delay = retry_delay
end

Instance Method Details

#lock(key) ⇒ Object

Blocks until lock is acquired or timeout.



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# File 'app/services/hyrax/lock_manager.rb', line 19

def lock(key)
  returned_from_block = nil

  pool.then do |conn|
    client(conn).lock(key, @ttl) do |locked|
      raise UnableToAcquireLockError unless locked
      returned_from_block = yield
    end
  end

  returned_from_block
rescue ConnectionPool::TimeoutError => err
  Hyrax.logger.error(err.message)
  raise(ConnectionPool::TimeoutError,
        "Failed to acquire a lock from Redlock due to a Redis connection " \
        "timeout: #{err}. If you are using Redis via `ConnectionPool` " \
        "you may wish to increase the pool size.")
end