Python Embedding Thread

[otr2@tuningchannel.de]

Hi :)

I want to run Python in my app. That works still fine. But my app
supports now Threads and I would like to know what to do, that it runs
without problems.

PyGILState_Rele ase and PyGILState_Ensu re should solve the problem
right? Where do I have to put this two commands around? between each
Command that increase, decrease a reference?



Currently, this is a small code-snippet that represents the part of
the code-execution:






PyObject *f_globals=NULL , *f_locals=NULL, *mod=NULL, *rv=NULL;

mod = PyImport_Import Module("__main_ _");
if (!mod)
return;

f_globals = PyModule_GetDic t(mod);
f_locals = PyDict_New();
PyDict_Update(f _locals, f_globals);
if (!f_locals) {
Py_DECREF(mod);
PyErr_Print();
return;
}



rv = PyRun_String( <my code , Py_file_input, f_locals,
f_locals);
if (!rv)
PyErr_Print();


Py_XDECREF(rv);
Py_DECREF(mod);
Py_DECREF(f_loc als);
Py_DECREF(f_loc als);






Thanks a lot for your help :)

[googler.1.webmaster@spamgourmet.com]

Re: Python Embedding Thread

Does anyone has a tip?

[Benjamin]

Re: Python Embedding Thread

On Jul 21, 6:56 am, o...@tuningchan nel.de wrote:

Hi :)
>
I want to run Python in my app. That works still fine. But my app
supports now Threads and I would like to know what to do, that it runs
without problems.
>
PyGILState_Rele ase and PyGILState_Ensu re should solve the problem
right? Where do I have to put this two commands around? between each
Command that increase, decrease a reference?

Two threads should not be running through the Python VM concurrently
in the same process. The GIL has to be held *any* time you use the
Python API. When you want to release the GIL (to process something in
C), use PY_BEGIN_ALLOW_ THREADS and PY_END_ALLOW_TH READS around the
places where threads can run.

>
Currently, this is a small code-snippet that represents the part of
the code-execution:
>
                                PyObject *f_globals=NULL , *f_locals=NULL, *mod=NULL, *rv=NULL;
>
                                mod = PyImport_Import Module("__main_ _");
                                if (!mod)
                                        return;
>
                                f_globals= PyModule_GetDic t(mod);
                                f_locals = PyDict_New();
                                PyDict_Update(f _locals, f_globals);
                                if (!f_locals) {
                                                Py_DECREF(mod);
                                                PyErr_Print();
                                                return;
                                }
>
                                rv = PyRun_String(    <my code , Py_file_input, f_locals,
f_locals);
                                if (!rv)
                                        PyErr_Print();
>
                                Py_XDECREF(rv);
                                Py_DECREF(mod);
                                Py_DECREF(f_loc als);
                                Py_DECREF(f_loc als);
>
Thanks a lot for your help :)

[Jaimy Azle]

Re: Python Embedding Thread

"Benjamin" <musiccompositi on@gmail.comwro te:

Two threads should not be running through the Python VM concurrently
in the same process. The GIL has to be held *any* time you use the
Python API. When you want to release the GIL (to process something in
C), use PY_BEGIN_ALLOW_ THREADS and
PY_END_ALLOW_TH READS around the
places where threads can run.

I think he is trying to call python from thread, according to the
documentation:

"Beginning with version 2.3, threads can now take advantage of the
PyGILState_*() functions to do all of the above automatically."
- http://docs.python.org/api/threads.html

I use it everywhere on my multithreaded server without problem.

Salam,

-Jaimy

[googler.1.webmaster@spamgourmet.com]

Re: Python Embedding Thread

Hi!

Thank you very much for your answers. I have a menue with a script in
it.
So my app starts a new thread for each script.

So I would like to run two scripts all the same time. Could someone
give me a tip,
what I have to set in my code?

Thank you :)

[googler.1.webmaster@spamgourmet.com]

Re: Python Embedding Thread

Hi!

I fixed the code. This code snippet runs in a seperate thread:


PyObject *dict=NULL;
PyGILState_STAT E state = PyGILState_Ensu re();
dict = CreateMyGlobalD ictionary();

PyRun_String(<m y code>, Py_file_input, dict, dict);

ReleaseGlobalDi ctionary(dict);

But it still does not work... :-/

[Jaimy Azle]

Re: Python Embedding Thread

<googler.1.webm aster@spamgourm et.comwrote:

I fixed the code. This code snippet runs in a seperate thread:
>
>
PyObject *dict=NULL;
PyGILState_STAT E state = PyGILState_Ensu re();
dict = CreateMyGlobalD ictionary();
>
PyRun_String(<m y code>, Py_file_input, dict, dict);
>
ReleaseGlobalDi ctionary(dict);
>
But it still does not work... :-/

Have you initialize interpreter with PyEval_InitThre ads? look at
http://www.python.org/doc/1.5.2/api/threads.html for more information.

Oh, btw... I did use python in a bit different scenario than you've
described. Since you attempt to run different script per-host thread, you
might need python multiple interpreter support, I suggest you take a look
mod_python implementation.

Salam,

-Jaimy.

[Graham Dumpleton]

Re: Python Embedding Thread

On Jul 23, 12:15 pm, "Jaimy Azle" <ja...@nospam.l og.web.idwrote:

<googler.1.webm as...@spamgourm et.comwrote:

I fixed the code. This code snippet runs in a seperate thread:

>

PyObject *dict=NULL;
PyGILState_STAT E state = PyGILState_Ensu re();
dict = CreateMyGlobalD ictionary();

>

PyRun_String(<m y code>, Py_file_input, dict, dict);

>

ReleaseGlobalDi ctionary(dict);

>

But it still does not work... :-/

>
Have you initialize interpreter with PyEval_InitThre ads? look athttp://www.python.org/doc/1.5.2/api/threads.htmlfor more information.
>
Oh, btw... I did use python in a bit different scenario than you've
described. Since you attempt to run different script per-host thread, you
might need python multiple interpreter support, I suggest you take a lookmod_pythoni mplementation.

Please don't look at mod_python. Current versions of mod_python don't
use Python simplified GIL APIs correctly.

http://issues.apache.org/jira/browse/MODPYTHON-217

Look at mod_wsgi instead, it is closer to the mark, although still has
some not quite cruft in there to workaround mistakes in mod_python for
case where mod_python and mod_wsgi are being loaded together. :-(

Graham