[Twisted-Python] Regarding Twisted Matrix

[Valeriy Pogrebitskiy]

Naman,

 

Another problem you might (possibly) be encountering - is the way your
server and/or client protocol is implemented. If you just inherit from
"plain" twisted.internet.protocol.Protocol - you are automatically using
write () and dataReceived() methods that do not implement buffering (it is
left up to developer). To enforce that line (string) oriented communication
works correctly - you might want to refactor to use
twisted.protocols.basic.LineReceiver instead. 

 

Kind regards,

 

Valeriy Pogrebitskiy

Email: vpogrebi at iname.com

 

 

-----Original Message-----
From: twisted-python-bounces at twistedmatrix.com
[mailto:twisted-python-bounces at twistedmatrix.com] On Behalf Of naman jain
Sent: Tuesday, October 27, 2009 6:36 AM
To: Twisted general discussion
Subject: Re: [Twisted-Python] Regarding Twisted Matrix

 

I tried to implement this:

parent_conn, child_conn = Pipe()

f = defer.Deferred()
f = threads.deferToThread(start_test.main_func, SCRIPT_PATH,
TEMP_OUTPUT_PATH, self.output_name, child_conn)

response = parent_conn.recv()
print response //prints like: initialization done
self.transport.write(response)

response = parent_conn.recv()
print response // configuration done
self.transport.write(response)

But get the same output ie all status messages concatenated and sent at
once.!

[Do we need to put some deffered/callback  mechanism on parent_conn.recv()
??
as that is the call blocking the thread waiting for reading.]

Any ideas ? How is such stuff done in twisted servers??

Naman



On Tue, Oct 27, 2009 at 7:03 AM, Nathan <nathan.stocks at gmail.com> wrote:

On Mon, Oct 26, 2009 at 11:44 PM, naman jain <namanvit at gmail.com> wrote:
> Hi,
>
> I have a client server model in twisted, where the server spawns a thread
(
> basically a test script in python that runs for about 20 mins)
> I want to track the progress of the thread, and send the progress to the
> client back
>
> So, I write something like this in my server:
>
> parent_conn, child_conn = Pipe()
> thread = Process(target = start_test.main_func, args=(SCRIPT_PATH,
> TEMP_OUTPUT_PATH, self.output_name, child_conn))
> thread.start()
>
> response = parent_conn.recv()
> print response //prints like: initialization done
> self.transport.write(response)
>
>
> response = parent_conn.recv()
> print response // configuration done
> self.transport.write(response)
>
> .
> .
> .
>
> thread.join()
>
>
> But the transport.write calls don't send at the same time. instead they
wait
> for the thread to finish (coz of thread.join) and then append all the
> response and send it back; like "initialization doneconfiguration
> done...done"
> thereby defeating the purpose of creating a thread.
>
> How do I give the control to the reactor to write the data back, and still
> keep the thread running?
> or is there any other way these kinda of progress can be tracked ?
> I am kinda stuck with this :(

I'm no expert with threads, but I don't see any deferToThread in
there, which is what people on this list tend to mention whenever
threading comes up.  Perhaps you need to switch to the "twisted way"
to create your thread?

http://twistedmatrix.com/documents/8.2.0/api/twisted.internet.threads.html

~ Nathan


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