Module: Revenant::MySQL

Extended by:
MySQL
Included in:
MySQL
Defined in:
lib/locks/mysql.rb

Instance Method Summary collapse

Instance Method Details

#acquire_lock(lock_name) ⇒ Object

Expects the connection to behave like an instance of Mysql If you need something else, replace acquire_lock with your own code. Or define your own lock_function while configuring a new Revenant task.



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# File 'lib/locks/mysql.rb', line 21

def acquire_lock(lock_name)
  begin
    acquired = false
    sql = lock_query(lock_name)
    connection.query(sql) do |result|
      acquired = result.fetch_row.first == "1"
    end
    acquired
  rescue ::Exception
    false
  end
end

#connection ⇒ Object

Currently defaults to the ActiveRecord connection if AR is loaded. Set this in your task setup block if that is not what you want.



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# File 'lib/locks/mysql.rb', line 40

def connection
  @connection ||= if defined?(ActiveRecord)
                    ActiveRecord::Base.connection.raw_connection
                  else
                    raise "No connection established or discovered. Use Revenant::MySQL::connection="
                  end
end

#connection=(conn) ⇒ Object 



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# File 'lib/locks/mysql.rb', line 48

def connection=(conn)
  @connection = conn
end

#lock_function ⇒ Object 



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# File 'lib/locks/mysql.rb', line 12

def lock_function
  Proc.new do |lock_name|
    ::Revenant::MySQL.acquire_lock(lock_name)
  end
end

#lock_query(lock_name) ⇒ Object 



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# File 'lib/locks/mysql.rb', line 34

def lock_query(lock_name)
  "select get_lock('#{lock_name}',0);"
end