Class: Bookie::Database::Lock

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
lib/bookie/database/lock.rb

Overview

Simulates table locks on databases that only have row locks

Based on kseebaldt.blogspot.com/2007/11/synchronizing-using-active-record.html

This should probably not be called within a transaction block. The transaction that this method creates uses the option :requires_new => true, limiting the negative effects of nested transactions, but concurrency safety is still strongly dependent on how the database engine handles locks.

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.[](name) ⇒ Object

Returns a lock by name



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# File 'lib/bookie/database/lock.rb', line 29

def self.[](name)
  @locks[name.to_sym] ||= find_by!(name: name.to_s)
end

Instance Method Details

#synchronize ⇒ Object

Acquires the lock, runs the given block, and releases the lock when finished



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# File 'lib/bookie/database/lock.rb', line 17

def synchronize
  transaction(:requires_new => true) do
    #Lock this record to be inaccessible to others until this transaction is completed.
    self.class.lock.find(id)
    yield
  end
end