In order to allow multiple processes to access a database (currently
SQLite) I want to run the process in a separate thread. Because it will
be accessed from multiple processes I intent to use Queues for shifting
messages back and forth. But none of the individuals processes will
know when all of the others are through. It there a way to properly
close the database, or does it need to be done from the parent process?
What I want to do is detect that a request to shutdown the Process has
been received, and then execute a close procedure that cleans things up
and shutdown. Terminate is the obvious procedure to use, but that comes
with a warning not to use it if there is an queue attached (and without
defining attached).
OTOH, since the queue will never be read after the process has been
shutdown, perhaps rendering it unusable is the proper thing.
Could someone comment on this step of the design?
The basic idea is:
class handledb(Process):
def __init__(self, q, otherstuff):
self.q = q
def run(self, msg):
while (true):
if self.q.empty():
sleep(someamountoftime)
else:
while (not self.q.empty()):
read and parse message
if message says to shutdown: self.shutdown()
def shutdown(self):
close things down
?? terminate ?? <<-- should this be done
while q is live?
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