Re: [Jython-dev] Custom JAR using standalone Jython 2.7.2 doesn't obey JYTHONPATH

[Alan K. <jyt...@xh...>]

Is this documentation out of date?

https://www.jython.org/registry.html

I always found it accurate in the past.

Alan.


On Sun, Mar 29, 2020, 8:43 PM Jeff Allen <ja...@fa...> wrote:

> I find initialisation difficult to follow too, although I have
> single-stepped it a hundred times. It may help to see where the environment
> is picked up now in the main program:
>
>
> https://github.com/jythontools/jython/blob/f77cc106afc4b0b61426ae4212c1e38d20ec942d/src/org/python/util/jython.java#L498
>
> and this simply involves getting things from the variables and setting
> them in the Java properties that get passed into initialisation:
>
>
> https://github.com/jythontools/jython/blob/f77cc106afc4b0b61426ae4212c1e38d20ec942d/src/org/python/util/jython.java#L709
>
> These are just the system properties in this case, although the
> initialisation is designed to allow them to come from elsewhere. (This is
> where I get lost, but the simple case is simple enough.)
>
> The manifest in the standalone JAR makes org.python.util.jython the main
> class, so it runs when you run the JAR with java -jar, therefore it picks
> up JYTHONPATH in the places I've linked, to be the default value of
> python.path. Or you could (I think) have given -Dpython.path=... to java
> instead.
>
> Sorry this change was a surprise. Of course, there are no major releases
> to come (no 2.8, I mean).
>
> Jeff
>
> Jeff Allen
>
> On 29/03/2020 10:06, Pekka Klärck wrote:
>
> Hi,
>
> I understand the idea to isolate the JAR from the environment, but I'm
> still a bit surprised that this was changed in a minor release and
> that when I use `java -jar jython-standalone-2.7.2.jar` JYTHONPATH is
> actually obeyed. Anyway, this isn't a big problem for us as we can
> explicitly handle JYTHONPATH ourselves. My current solution is doing
> that on Python side and calling the function that does it as part of
> creating the runner on Java side. You can see it here if you are
> interested:https://github.com/robotframework/robotframework/commit/cce18967c8b27a14239112b74b66e57e4584f3b0
>
> I also looked at configuring `python.path` via `PythonInterpreter`. If
> I understood it correctly, I should call
> `PythonInterpreter.initialize` before creating a `PythonInterpreter`
> instance and the `initialize` method needs also arguments in addition
> to properties. Due to how our code is structured and arguments are
> passed nowadays, that looked rather complicated. If there's some
> easier way to set `pytohn.path` perhaps it could work. That said, I'm
> fine with the above solution that seems to work fine in our tests.
>
> Thanks again for Jython 2.7.2 everyone involved!
>
> Cheers,
>     .peke
>
> la 28. maalisk. 2020 klo 13.48 Jeff Allen (ja...@fa...) kirjoitti:
>
>
> I think this is because you are no longer running the interpreter via the jython.main() programme. Try setting in the Java System property python.path, what you might have put in JYTHONPATH.
>
> If you are initialising Jython with your own properties object(s) it should go in the earliest consulted, I suspect.
>
> Rationale
>
> The design intent in Jython is that it use the registry (Java properties) as the means of configuring the interpreter. (Well, it seems to have been that from early on: I'm inferring a principle from the implementation.) Java promotes a platform-independent world where the Java interpreter can be launched any number of ways, and there isn't necessarily a shell environment in the way Unix and C have led us to expect. System properties, however, are a Java feature so it must always be possible to set them.
>
> The main program, that you might invoke from the console (even if it is via the java command rather than the launcher), sits as a bridge between console world and Java world, and so I think it is only there that environment variables should be consulted, rather than in a scattered way. (This was mostly true already, but maybe not for JYTHONPATH.) Implementation of the -E option (ignore environment variables), and of trying to be more faithful to CPython in our main program, is behind making this absolute.
>
> Jeff
>
> On 27/03/2020 21:59, Pekka Klärck wrote:
>
> Hi,
>
> In the Robot Framework project
> (https://github.com/robotframework/robotframework) one of our
> distributions is a standalone JAR that is built on top of standalone
> Jython. We've earlier used Jython 2.7.0, but there have been lot of
> fixes since that and we are now planning to switch to Jython 2.7.2. I
> have already changed our build scripts and have been running all our
> acceptance tests using the new JAR.
>
> Things have worked pretty well with the new JAR otherwise, but it
> seems it doesn't obey JYTHONPATH set externally before execution.
> Executing Python code can see the environment variable, but Python
> modules in directories listed in it cannot be imported. I just tested
> that if I build a JAR from same sources with Jython 2.7.0, JYTHONPATH
> works as expected.
>
> The strange thing is that when I tested with the standalone Jython
> 2.7.2 alone, it did handle JYTHONPATH just fine. This got me thinking
> that perhaps we are somehow embedding Jython wrong. Are there some
> know changes related to embedding Jython using PythonInterpreter?
> Should we perhaps configure it somehow to get JYTHONPATH processed
> correctly? The code currently just initialized PythonInterpreter
> without any arguments and then calls `interpreter.exec(code)`. You can
> find the full code here:https://github.com/robotframework/robotframework/blob/master/src/java/org/robotframework/RobotRunner.java
>
> One workaround for us is processing JYTHONPATH in our code and I
> already tested that it works. If that turns out to be the only
> solution, I just need to find a way to do that only when using the JAR
> distribution.
>
> Cheers,
>     .peke
>
>
>
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