Re: [SQLObject] SQLObject+Quixote+SCGI

[Oleg B. <ph...@ma...>]

On Wed, Oct 27, 2004 at 11:15:29AM +0200, Ksenia Marasanova wrote:
> Op 24-okt-04 om 14:04 heeft Oleg Broytmann het volgende geschreven:
> >   People, how do you handle forks and transactions?
> 
> I am on the same path (SQLObject + Quixote + SCGI), but earlier - 
> worring about more primitive things yet :) But I share your concern. 
> There is a mention of preferred connection approach in Quixote on this 
> page: http://wiki.sqlobject.org/connections.html, but it's all I can 

   I saw it already, of course. Actually, I have searched SQLObject and
Quixote mailing lists using Google and Gmane.

> find. Maybe it's related to the forking problem?
> More comments are greatly appreciated...

   Well, now I do as follows. Firest, transactions. I initialize
transactions in my DB.py, where I declare all my tables:

from Cfg import dbName, dbUser, dbPassword, dbHost
dbConn = PostgresConnection(db=dbName, user=dbUser, passwd=dbPassword, host=dbHost)
dbConn.debug = True

transaction = dbConn.transaction()
transaction._makeObsolete() # prepare for .begin()

def transaction_begin():
   transaction.begin()

def transaction_commit():
   transaction.commit()

def transaction_rollback():
   transaction.rollback()


# the parent class for all my tables
class Table(SQLObject):
   _connection = transaction


   In the main script:

class MyPublisher(Publisher):

    def process_request(self, request, env):
        from DB import transaction_begin, transaction_commit, transaction_rollback
        transaction_begin()
        try:
           output = Publisher.process_request(self, request, env)
        except:
           transaction_rollback()
           raise
        else:
           transaction_commit()
        return output


   Second, forking. I have to delay importing DB until after forking.
Actually, I import it now only when it is required. In main script right
in process_request(), in other modules - in appropriate methods. This
late import delays creating the connection, so the real connection to
the database is being created late enough - after SCGI has forked.

Oleg.
-- 
     Oleg Broytmann            http://phd.pp.ru/            ph...@ph...
           Programmers don't die, they just GOSUB without RETURN.