[OPEN-ILS-DEV] OpenSRF 101

[Bill Erickson]

Hi Michael,

If you want to send your diffs as a patch file (with DCO [1]), I'll merge
them into OpenSRF trunk in preparation for the 2.0 release.

-b

[1] http://svn.open-ils.org/trac/ILS/browser/trunk/DCO-1.1.txt


On Sat, Oct 30, 2010 at 6:23 PM, Michael J. Giarlo <
leftwing at alumni.rutgers.edu> wrote:

> Thanks a bunch, Dan; my test Python service is now running.  Thanks
> also to Jeff, who replied with much the same suggestions on my gist.
>
> Some notes below.
>
> On Sat, Oct 30, 2010 at 03:59, Dan Scott <dan at coffeecode.net> wrote:
> >
> > First up: your config settings look pretty good to me. Bravo! One thing
> > to point out, though, is that the Python service needs to be implemented
> > as a module available from sys.path, and the name of the module is what
> > you need to specify as the content of the <implementation> element in
> > the application config section. So I copied osrf_reverse.py to
> > /usr/lib/python2.6/site-packages/. and changed
> > <implementation>osrf.test</implementation> to
> > <implementation>osrf_reverse</implementation>
>
> Aha, that makes sense.  What I did:
>
>  * Added an /opensrf/lib/python directory
>  * Symlinked my osrf_test.py from /opensrf/lib/python into my
> workspace, so I can continue coding in my usual place
>  * Pulled opensrf.py from the source into /opensrf/bin
>  * Tweaked opensrf.py's default path by adding:
>    sys.path.append(os.path.join(os.path.dirname(__file__), "lib",
> "python"))
>
> > Second: to start the Python service, you don't run it directly; instead,
> > you use the Python controller script to run it (similar to how
> > osrf_ctl.sh invokes opensrf-perl.pl to start the Perl services). This
> > controller script can be found in src/python/opensrf.py - we don't
> > install it into /openils/bin/ yet because nobody was using Python in
> > OpenSRF yet - so let's give it a shot with the following (using "-l"
> > assuming that we're pointing to the "<localhost>" set of services) as
> > the opensrf user:
>
> Great.  I also tweaked osrf_ctl.sh to hook into opensrf.py.
>
> Then I noticed some odd behavior re what's returned via
> osrf.set.get('apps').  One key returned in the dict is "#comments",
> which does not contain the 'language' key, so a KeyError exception is
> raised.  Fixed that with the following diff in opensrf.py:
>
> 114c112
> <         if isinstance(svc, dict) and 'language' in svc and
> svc['language'] == 'python':
> ---
> >         if isinstance(svc, dict) and svc['language'] == 'python':
>
>
> > ... this is a painful Python DNS issue that is fortunately nicely
> > documented in the OpenSRF README - see "dnsmasq".
>
> I did indeed run into this, and the stuff in the README worked
> brilliantly.  Huzzah for good documentation!
>
> > YAY! Looks like an off-by-one error on the "n" but
> > otherwise that's what we want.
>
> Yep.  Simplified my reverse_text method to a one liner:
>
>    request.respond(message[::-1])
>
> No more off-by-one.
>
> > However, given an actual user of this
> > code, I'll be happy to put some energy into refining the packaging to
> > (for example) get opensrf.py installed if people choose --enable-python,
> > provide some more examples / test cases, put together some docs, etc.
>
> It's early days yet, but I can see the potential in using OpenSRF for
> what we're about to start prototyping at Penn State.  If so, we're
> pretty gung ho about Python, so we're likely to cross paths again,
> i.e., I think we can help you help us.
>
> Thanks again, Dan & Jeff!
>
> -Mike
>
> P.S. Here are the osrf_ctl.sh diffs, trivial though they are:
>
> 51,53d50
> <     start_python
> <     stop_python
> <     restart_python
> 159,179d155
> < start_python() {
> <     echo "Starting OpenSRF Python";
> <     OPT_LOCAL=""
> <     if [ "$OSRF_HOSTNAME" = "localhost" ]; then
> <       OPT_LOCAL="-l"
> <     fi
> <     opensrf.py -d -p $OPT_PID_DIR -f $OPT_CONFIG -a start_all $OPT_LOCAL
> <     return 0;
> < }
> <
> < stop_python() {
> <     echo "Stopping OpenSRF Python";
> <     OPT_LOCAL=""
> <     if [ "$OSRF_HOSTNAME" = "localhost" ]; then
> <       OPT_LOCAL="-l"
> <     fi
> <     opensrf.py -p $OPT_PID_DIR -f $OPT_CONFIG -a stop_all $OPT_LOCAL
> <     sleep 1;
> <     return 0;
> < }
> <
> 223,225d198
> <       "start_python") start_python;;
> <       "stop_python") stop_python;;
> <       "restart_python") stop_python; start_python;;
> 229,234c202,207
> <       "start_osrf") start_perl; start_c; start_python;;
> <       "stop_osrf") stop_perl; stop_c; start_python;;
> <       "restart_osrf") stop_perl; stop_c; stop_python; start_perl;
> start_c; start_python;;
> <       "stop_all") stop_c; stop_perl; stop_python; stop_router;;
> <       "start_all") start_router; start_perl; start_c; start_python;;
> <       "restart_all") stop_c; stop_perl; stop_python; stop_router;
> start_router; start_perl; start_c; start_python;;
> ---
> >       "start_osrf") start_perl; start_c;;
> >       "stop_osrf") stop_perl; stop_c;;
> >       "restart_osrf") stop_perl; stop_c; start_perl; start_c;;
> >       "stop_all") stop_c; stop_perl; stop_router;;
> >       "start_all") start_router; start_perl; start_c;;
> >       "restart_all") stop_c; stop_perl; stop_router; start_router;
> start_perl; start_c;;
>



-- 
Bill Erickson
| VP, Software Development & Integration
| Equinox Software, Inc. / Your Library's Guide to Open Source
| phone: 877-OPEN-ILS (673-6457)
| email: erickson at esilibrary.com
| web: http://esilibrary.com
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