Embedding version in command-line program

[Loris Bennett]

Hi Heinrich,

Heinrich Kruger <heindsight at kruger.dev> writes:

> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Thursday, October 8, 2020 2:00 PM, Loris Bennett <loris.bennett at fu-berlin.de> wrote:
>
>> Marco Sulla Marco.Sulla.Python at gmail.com writes:
>>
>> > On Wed, 7 Oct 2020 at 14:16, Loris Bennett loris.bennett at fu-berlin.de
>> > wrote:
>> >
>> > > But the toml file isn't part of the distribution and so it won't be
>> > > installed.
>> > > I suppose I could write a separate program which parses the toml file
>> > > and then just injects the version into init.py.
>> >
>> > Yes, I do not know poetry, but I suppose you can generate it in its
>> > setup. I usually create a separate VERSION file and I read it in
>> > init.py. Other people creates a version.py that is evaled inside
>> > init.py
>>
>> I ended up using the module
>>
>> poetry_version
>>
>> which allows one to extract the version like this:
>>
>> import poetry_version
>>
>> version = poetry_version.extract(source_file=file)
>>
>
> It looks to me like that package also just reads the pyproject.toml file.
>
> You could try using the "importlib.metadata" module
> (https://docs.python.org/3.8/library/importlib.metadata.html). If you're still
> using python 3.7 (or older) you can install importlib-metadata from PyPI
> (https://pypi.org/project/importlib-metadata/).
>
> Try putting something like
>
> ```
> from importlib import metadata
>
> __version__ = metadata.version(__name__)
> ```
> in your __init__.py file.
>
> Then you can do something like:
> ```
> from . import __version__
>
> def main():
>     print(f"Version: {__version__}")
> ```
>
> Bear in mind that this would only work if your package is installed (e.g. in
> virtual environment). Otherwise the `metadata.version(__name__)` call will fail
> with a `importlib.metadata.PackageNotFoundError` exception (of course you could
> catch that and fall back to trying to read the pyproject.toml file).

You're right of course, that 'poetry_version' just looks at the toml file.

I'm using Python 3.6, so I had to do

  import importlib_metadata as metadata

which works, although as you mention in you caveat, it is a bit of a
pain that this gives me the version of the installed version.

As someone who has only dabbled in Python up to know, I'm slightly
surprised that there is no obvious and accepted way of keeping the
version in the metadata of a module and the version which a command-line
wrapper around the module in sync.  Is my expectation that this should
be straightforward misguided?

<grumble>At the least I would have expected that, since poetry regards
the toml file as the primary source of project data, although it isn't
part of the installed package, that the 'poetry version' command would
offer the option of bumping the version directly in the code.<grumble/>

Cheers,

Loris

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