As an alternative, how about the python gods quit this ongoing assault on
backwards compatibility.
Just saying...
The whole venv seems to be a work-around to the disconnect between OS-based
python versions not advancing
and Python having this obsession with breaking things over minor revisions.
Wrong place, wrong time. Sorry.
Chris
On Tuesday, October 21, 2025 at 11:53:33 AM UTC-6 vince wrote:
> If pip bothers you, don't use pip. Use the packaged versions. That's why
> they're there...
>
> Long TL;DR; follows.....
>
> Some thoughts on risk mitigation from a too many decades to admit retired
> sysadmin and custom linux os developer at $work....
>
> 1. os upgrades can and do break things on every os I've ever seen
>
> - 'you' control whether your os updates things
> - you also control 'which' things you will permit to be updatable
> - you can pin packages to 'not' update if you are so inclined
> - for debian-like (apt-mark)
> - for redhat-like (there are several ways to do this)
>
> 2. if you understand your risks, you can choose to simply not update your
> os
>
> - yes I know others will differ in opinion here, everybody has a
> different risk decision to make
> - FWIW - I never update 'anything' on my home LAN-only weewx system.
> Never.
> - why ? Because I only upload outbound to Internet sites
> - and my gateway blocks all incoming traffic from Internet
>
>
> - just mentioning it above, although others can/will differ in
> opinion, so I don't want to start a flame war on that one
> - ultimately, the os upgrade setup is the admin's choice
>
> 3. for me, I run pip for a couple reasons
>
> - packaged installs tend, for me, to be less stable/predictable in
> what they will upgrade, sometimes os by os
> - packaging is hard. Real hard. And real painful for the
> developer. (many thanks to matthew there)
>
>
> - for pip I know exactly what it'll do, and it has been 100%
> rock-solid for me in literally dozens of installs
>
> 4. creating your venv slightly differently to select a specific python
> version can help a little
>
> - "python3 -m venv" expects the os default python version to never
> change
> - but "python3.11 -m venv" will use a specific python version
> available on the system
>
>
> - so in the latter case, unless the python3.11 packages get deleted,
> your venv will be fine
> - and if an os upgrade (bookworm=>trixie) 'did' delete that version,
> just add it back in ('apt install python3.11')
>
> 5. reinstalling via pip is not 'that' painful really if you do a 'little'
> up front work even if you've added a lot of python libraries
>
> - on a working system save your venv python setup to a file
> - activate your venv
> - source ~/weewx-venv/bin/activate
> - save a listing of the libs and their versions to a file in a
> persistent location (weew-data)
> - pip3 freeze > ~/weewx-data/requirements.txt
>
>
> - if you ever have to rebuild your venv from scratch
> - create a new venv
> - python3 -m venv weewx-venv
> - activate your new venv
> - source weewx-data/bin/activate
> - use the saved requirements.txt file to reinstall your libs
> - pip3 install -r ~/weewx-data/requirements.txt
> - and you'll have a new complete weewx-venv with all the libs you
> had before in the old version
>
> Personally - I kinda like item (5) above a lot.
>
> - stash a requirements.txt file that itemizes your setup
> - use it if you ever 'do' need to recreate a previously working setup
> - all without needing to remember what you added months or years ago
> - quick test here in debian took under 20 seconds end-to-end to
> rebuild. Really.
>
> On Tuesday, October 21, 2025 at 7:29:57 AM UTC-7 Tom Keffer wrote:
>
>> Yes, pip installs can be vulnerable to operating system upgrades. Then
>> again, so can package installs --- see the recent thread on the
>> disappearance of the function locale.format() when the system Python was
>> upgraded to V3.12.
>>
>> Still, the pip install has advantages. Because of the clean separation of
>> code from user state, the old virtual environment can always be deleted,
>> then recreated by following the pip install instructions.
>>
>> Alternatively, one could create the virtual environment using
>> the --copies flag:
>>
>> python -m venv --copies weewx-venv
>>
>>
>> This will install copies of the Python interpreter instead of symlinking.
>> Of course, expect it to take up a lot more space.
>>
>> Still another alternative is to use Docker.
>>
>> -tk
>>
>>
>> On Tue, Oct 21, 2025 at 7:01 AM [email protected] <[email protected]>
>> wrote:
>>
>>> I'd just like to chime in here.
>>> I certainly do not like the pip install.
>>> It works fine for me.
>>> Until an OS upgrade. Then it seems the choices are either rebuild the
>>> machine and start from scratch so to speak.
>>> Fiddle with finding every instance of the path to the missing python and
>>> edit it.
>>> Or hard link.
>>> Or symlink.
>>>
>>> Or...
>>>
>>> Yeah, I know. Don't upgrade. Not the best answer to me.
>>> I may revert to a deb install when I rebuild the weewx machine to solve
>>> these errors after the upgrade to Trixie.
>>> Shoot, for me, in the venv there isn't a pip and it was not possible to
>>> reinstall pip for reasons known only to the gods.
>>> Luckily, I run on proxmox and rolled back to my previous state.
>>>
>>>
>>> My 10 cents
>>>
>>> On Monday, October 20, 2025 at 10:41:39 PM UTC-4 Tom Keffer wrote:
>>>
>>>> It is customary when using a venv interactively, but it's not actually
>>>> necessary. As an alternative, you can use an absolute path to the Python
>>>> interpreter inside the venv. That's enough for it to find its packages.
>>>>
>>>> On Mon, Oct 20, 2025 at 4:37 PM vince <[email protected]> wrote:
>>>>
>>>>> Yes.
>>>>>
>>>>> On Monday, October 20, 2025 at 3:33:33 PM UTC-7 Jobu wrote:
>>>>>
>>>>>> A bit of a tangent, but is it customary to run `activate` from a venv
>>>>>> before using it in systematic use cases like this?
>>>>>>
>>>>>> On Monday, October 20, 2025 at 4:22:34 PM UTC-5 vince wrote:
>>>>>>
>>>>>>> Which 'what' is accurate ?
>>>>>>>
>>>>>>> It sounds like your os has a different system-level python version
>>>>>>> than your pre-existing venv, perhaps from an os upgrade. It's happened
>>>>>>> to
>>>>>>> others.
>>>>>>>
>>>>>>> See a similar thread at
>>>>>>> https://groups.google.com/g/weewx-user/c/04WSgv2Ze7g/m/9nlZklaPAgAJ
>>>>>>> - there are multiple ways to work this one, but be sure to make certain
>>>>>>> your systemd service file (or equivalent) matches what is in the venv.
>>>>>>> I
>>>>>>> don't know kali well enough to know how it handles startup files.
>>>>>>>
>>>>>>> Look at your weewx-venv/bin symlinks and you will likely see that
>>>>>>> python3 resolves to whatever your os python version is, and 'not' a
>>>>>>> specific version that was there when you set up the venv. You might be
>>>>>>> able to just fix the symlink therein to point to python3.12 (to match
>>>>>>> the
>>>>>>> venv) if you have multiple python versions on the os. If that doesn't
>>>>>>> work
>>>>>>> you'll need to reinstall your venv contents and fix up your startup
>>>>>>> file to
>>>>>>> match.
>>>>>>>
>>>>>>> This is not a weewx bug. It is a (massive) pain in the neck
>>>>>>> non-feature from the python team.
>>>>>>>
>>>>>>> On Monday, October 20, 2025 at 1:55:15 PM UTC-7 Dan Hinckley wrote:
>>>>>>>
>>>>>>>> Starting weewx throws this error:
>>>>>>>>
>>>>>>>> Oct 20 16:50:47 kali-linux-2024-2 systemd[1]: Started weewx.service
>>>>>>>> - WeeWX weather system.
>>>>>>>> Oct 20 16:50:48 kali-linux-2024-2 python3[2820]:
>>>>>>>> /home/house/weewx-venv/bin/python3: can't open file
>>>>>>>> '/home/house/weewx-venv/lib/python3.12/site-packages/weewxd.py':
>>>>>>>> [Errno 2]
>>>>>>>> No such file or directory
>>>>>>>>
>>>>>>>> Which is accurate. That venv has python 3.13
>>>>>>>>
>>>>>>>> How do I cure this?
>>>>>>>
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>>>
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