[OPEN-ILS-DEV] OpenSRF 101

[Michael J. Giarlo]

Patch w/ DCO tarball attached to this email.  Apologies for newb
mistakes -- let me know if I should make any changes.  Patch includes
two diffs in opensrf.py, and a bunch of stuff in osrf_ctrl.sh.in to
enable python services -- though perhaps these changes should live in
a Makefile and should be dependent on the --enable-python option.

-Mike



On Thu, Nov 4, 2010 at 08:46, Bill Erickson <erickson at esilibrary.com> wrote:
>
> 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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