WeeWX error on Trixie during startup

[David Enstrom]

Just installed Trixie on my Raspberry Pi 3. I created a virtual environment and installed Python, required software, and WeeWX using PIP. The weather hardware is from BC Robotics, which has worked beautifully for many years. I wrote the driver many years ago.

My test app runs fine. I can also run WeeWX manually (i.e., activate my weeve virtual environment and then run 'weewxd') and it operates just fine. However, if I start weewx using the command 'sudo systemctl start weewx' and check the system log it does not start properly. I'm very confused by the following error in the log:

Oct 08 08:35:08 raspberrypi systemd[1]: Started weewx.service - WeeWX weather system.
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Initializing weewxd version 5.1.0
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Command line: /home/dave/weeve/lib/python3.13/site-packages/weewxd.py /home/dave/weewx-data/weewx.conf
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Using Python: 3.13.5 (main, Jun 25 2025, 18:55:22) [GCC 14.2.0]
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Located at:   /home/dave/weeve/bin/python3
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Platform:     Linux-6.12.47+rpt-rpi-v8-aarch64-with-glibc2.41
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Locale:       'en_CA.UTF-8'
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Entry path:   /home/dave/weeve/lib/python3.13/site-packages/weewxd.py
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: WEEWX_ROOT:   /home/dave/weewx-data
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Config file:  /home/dave/weewx-data/weewx.conf
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: User module:  /home/dave/weewx-data/bin/user
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Debug:        0
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: User:         dave
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Group:        dave
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO __main__: Groups:       adm dialout cdrom sudo audio video plugdev games users netdev lpadmin gpio i2c spi render input dave
Oct 08 08:35:09 raspberrypi weewxd[4962]: INFO weewx.engine: Loading station type BCRobotics (user.BCRobotics)
Oct 08 08:35:09 raspberrypi python3[4962]: 2025-10-08 08:35:09 xCreatePipe: Can't set permissions (436) for //.lgd-nfy0, No such file or directory
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__: Caught OSError: [Errno 2] No such file or directory: '.lgd-nfy-3'
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****  Traceback (most recent call last):
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/home/dave/weeve/lib/python3.13/site-packages/weewxd.py", line 121, in main
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      engine = weewx.engine.StdEngine(config_dict)
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/home/dave/weeve/lib/python3.13/site-packages/weewx/engine.py", line 80, in __init__
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      self.setupStation(config_dict)
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/home/dave/weeve/lib/python3.13/site-packages/weewx/engine.py", line 104, in setupStation
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      __import__(driver)
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      ~~~~~~~~~~^^^^^^^^
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/home/dave/weewx-data/bin/user/BCRobotics.py", line 29, in <module>
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      import board
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/home/dave/weeve/lib/python3.13/site-packages/board.py", line 51, in <module>
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      from adafruit_blinka.board.raspberrypi.raspi_40pin import *
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/home/dave/weeve/lib/python3.13/site-packages/adafruit_blinka/board/raspberrypi/raspi_40pin.py", line 6, in <module>
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      from adafruit_blinka.microcontroller.bcm283x import pin
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/home/dave/weeve/lib/python3.13/site-packages/adafruit_blinka/microcontroller/bcm283x/pin.py", line 7, in <module>
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      from adafruit_blinka.microcontroller.generic_linux.rpi_gpio_pin import Pin
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/home/dave/weeve/lib/python3.13/site-packages/adafruit_blinka/microcontroller/generic_linux/rpi_gpio_pin.py", line 6, in <module>
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      from RPi import GPIO
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/usr/lib/python3/dist-packages/RPi/GPIO/__init__.py", line 14, in <module>
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      import lgpio
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/usr/lib/python3/dist-packages/lgpio.py", line 562, in <module>
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      _notify_thread = _callback_thread()
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****    File "/usr/lib/python3/dist-packages/lgpio.py", line 504, in __init__
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****      self._file = open('.lgd-nfy{}'.format(self._notify), 'rb')
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****                   ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****  FileNotFoundError: [Errno 2] No such file or directory: '.lgd-nfy-3'
Oct 08 08:35:09 raspberrypi weewxd[4962]: CRITICAL __main__:     ****  Waiting 10 seconds then retrying...

HELP!!

[matthew wall]

hi david,

perhaps others in this forum could help if you post your driver code, but here is a guess:

it looks like your driver is using a file related to gpio (perhaps a socket?) whose location is not explicitly specified, so when you run it as you the file is in a directory in which you have permissions, but when you run it as a daemon (under the control of systemd) the file ends up somewhere that you do *not* have permissions.

take a look at your driver code for details about how you do the gpio, and see if you can specify the location explicitly, e.g., to /var/tmp or /tmp

m

> --
> You received this message because you are subscribed to the Google Groups "weewx-user" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+...@googlegroups.com.
> To view this discussion visit https://groups.google.com/d/msgid/weewx-user/df68a173-9654-4843-80fb-5b450d76d1cfn%40googlegroups.com.

[David Enstrom]

I think something has changed with the WeeWX startup (as daemon) under Trixie. This is the same error, with a solution:

      https://github.com/gpiozero/gpiozero/discussions/1153

I logged the working directory at start up of WeeWX as a daemon:  Current working directory: /   

This seems rather odd!

So, when I change it to /tmp/ in my BCRobotics.py driver, and it works just fine! (i.e., os.chdir("/tmp/")

I logged the change:

Current working directory: /
New working directory: /tmp

So, it is fixed (WeeWX runs fine), but I am still confused as to the root cause! Trixie?

[vince]

If by many years ago you mean you were previously successfully running weewx v4 or earlier (which ran as root) and it broke now using weewx v5 (which runs as a unprivileged user) then that’s the cause. Your unprivileged process tried to write to a privileged location.

If you were previously running weewx v5 and the only change you made was updating your os, then I no ideas here.

[David Enstrom]

I was previously running WeeWX V5 with no issues ... really the only change was the OS, to Trixie.

[Graham Eddy]

i upgraded bookworm to trixie with no such issues. it is specific to this installation. i think the clue is all in the error message:

**** FileNotFoundError: [Errno 2] No such file or directory: '.lgd-nfy-3'

⊣GE⊢

[David Enstrom]

Clarification: currently running WeeWX V5.0.2 

So something has changed to cause this error: either the OS to Trixie or WeeWX to V5.1.0

[Christian Peters]

Hi,

I just ran into the same problem: rpi model B, 32 bit Debian Trixie, weewx latest, as3935.py. 

Not sure howto fix it...!?

Installed with apt, no venv.

Any help would be great. 

Regards,

Christian 

 

INFO weewx.engine: Loading station type Simulator (weewx.drivers.simulator)
2026-07-05T11:31:26.452462+02:00 webpi weewxd[1283]: 2026-07-05 11:31:26 xCreatePipe: Can't set permissions (436) for //.lgd-nfy0, No such file or directory
2026-07-05T11:31:26.459798+02:00 webpi weewxd[1283]: CRITICAL __main__: Caught OSError: [Errno 2] No such file or directory: '.lgd-nfy-3'
2026-07-05T11:31:26.515718+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****  Traceback (most recent call last):
2026-07-05T11:31:26.530273+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "/usr/share/weewx/weewxd.py", line 121, in main
2026-07-05T11:31:26.531269+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      engine = weewx.engine.StdEngine(config_dict)
2026-07-05T11:31:26.532277+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "/usr/share/weewx/weewx/engine.py", line 89, in __init__
2026-07-05T11:31:26.533171+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      self.loadServices(config_dict)
2026-07-05T11:31:26.534056+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
2026-07-05T11:31:26.534935+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "/usr/share/weewx/weewx/engine.py", line 157, in loadServices
2026-07-05T11:31:26.540367+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      obj = weeutil.weeutil.get_object(svc)(self, config_dict)
2026-07-05T11:31:26.541467+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****            ~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^
2026-07-05T11:31:26.542358+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "/usr/share/weewx/weeutil/weeutil.py", line 1405, in get_object
2026-07-05T11:31:26.543236+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      module = importlib.import_module(module_name)
2026-07-05T11:31:26.549302+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "/usr/lib/python3.13/importlib/__init__.py", line 88, in import_module
2026-07-05T11:31:26.560050+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      return _bootstrap._gcd_import(name[level:], package, level)
2026-07-05T11:31:26.561043+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****             ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-07-05T11:31:26.562020+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
2026-07-05T11:31:26.562909+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
2026-07-05T11:31:26.563908+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
2026-07-05T11:31:26.564802+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
2026-07-05T11:31:26.570396+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "<frozen importlib._bootstrap_external>", line 1026, in exec_module
2026-07-05T11:31:26.580942+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
2026-07-05T11:31:26.584793+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "/etc/weewx/bin/user/as3935.py", line 74, in <module>
2026-07-05T11:31:26.587229+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      import RPi.GPIO as GPIO
2026-07-05T11:31:26.591976+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "/usr/lib/python3/dist-packages/RPi/GPIO/__init__.py", line 14, in <module>
2026-07-05T11:31:26.600240+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      import lgpio
2026-07-05T11:31:26.602930+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "/usr/lib/python3/dist-packages/lgpio.py", line 563, in <module>
2026-07-05T11:31:26.607009+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      _notify_thread = _callback_thread()
2026-07-05T11:31:26.612416+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****    File "/usr/lib/python3/dist-packages/lgpio.py", line 504, in __init__
2026-07-05T11:31:26.615416+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****      self._file = open('.lgd-nfy{}'.format(self._notify), 'rb')
2026-07-05T11:31:26.621176+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****                   ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-07-05T11:31:26.623563+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****  FileNotFoundError: [Errno 2] No such file or directory: '.lgd-nfy-3'
2026-07-05T11:31:26.624494+02:00 webpi weewxd[1283]: CRITICAL __main__:     ****  Waiting 10 seconds then retrying...

[Susan Mackay]

I am certainly no believer in AI so please treat this with all due caution...

I was intrigued to know what 'ldg-nfy0' was so I Googled it. The AI summary provided:

```

.lgd-nfy0 is a temporary named pipe file created by the lgpio Python library, which is commonly used on Raspberry Pi devices for managing hardware pins. The file acts as a notification channel for handling hardware events and interrupts. [1, 2]

When scripts utilizing high-level libraries like gpiozero crash or report an "Operation not permitted" or "Can't set permissions" error, it is almost always due to this file being generated in a directory where your program does not have write permissions. [1, 2]

Why the Error Happens

• Systemd Services: Running your script as a boot service defaults the working directory to the root directory (/), where standard scripts are forbidden to write. [1]
• External Storage: Running scripts directly from a USB flash drive or restricted media directory often conflicts with Linux file permission policies. [1, 2]

How to Fix It

You can easily resolve this issue using one of the following proven methods:

Method 1: Change the Working Directory Environment Variable (Recommended) [1]

You can force lgpio to create its temporary notification pipes in the system's global temporary folder (/tmp), where all users have write permissions. [1, 2]

1. Open your terminal.
2. Define the global environment variable by running:
   bash

   export LG_WD=/tmp

   Use code with caution.
3. To make this change permanent, add export LG_WD=/tmp to your system profile or your shell configuration file (like ~/.bashrc). [1]

Method 2: Fix the Systemd Service File

If your script crashes specifically when executed via a systemd service, you must explicitly declare a writable directory. [1]

1. Open your service configuration file (e.g., /etc/systemd/system/myscript.service).
2. Add a WorkingDirectory parameter under the [Service] block pointing to a path owned by your script's user:
   ini

   [Service] WorkingDirectory=/home/your_username/ ExecStart=/usr/bin/python3 /home/your_username/script.py

   Use code with caution.
3. Reload the system daemon and restart your service:
   bash

   sudo systemctl daemon-reload sudo systemctl restart myscript.service

   Use code with caution.
   [1]

Method 3: Change Directory Inside the Python Script

If you do not want to change system files, you can force the Python runtime to change its execution context to a writable folder before invoking any hardware controls. Add these lines to the absolute top of your script: [1]

python

import os os.chdir('/tmp') # Safely redirects pipe generation to the temporary folder from gpiozero import LED # Or any other hardware libraries

Use code with caution.

```

[Christian Peters]

Thanks for the ideas.

Found this solutions, too ... but non if it worked.
I will try to uninstall weewx as debian pacekt and try installing it in
a venv, maybe more luck...

Regards,

Christian

Am 06.07.26 um 06:04 schrieb Susan Mackay:

> I am certainly no believer in AI so please treat this with all due
> caution...
>
> I was intrigued to know what 'ldg-nfy0' was so I Googled it. The AI summary
> provided:
>
> ```
> .lgd-nfy0 is a temporary named pipe file created by the lgpio Python
> library, which is commonly used on Raspberry Pi devices for managing
> hardware pins. The file acts as a notification channel for handling
> hardware events and interrupts. [1

> <https://community.openhab.org/t/python3-binding-discussion/161914/143>, 2
> <https://forum.openmarine.net/showthread.php?tid=6149&page=2>]

> When scripts utilizing high-level libraries like gpiozero crash or report
> an "Operation not permitted" or "Can't set permissions" error, it is almost
> always due to this file being generated in a directory where your program
> does not have write permissions. [1

> <https://github.com/gpiozero/gpiozero/issues/1106>, 2
> <https://forums.raspberrypi.com/viewtopic.php?t=379869>]
> Why the Error Happens
>
> - Systemd Services: Running your script as a boot service defaults the

> working directory to the root directory (/), where standard scripts are
> forbidden to write. [1

> <https://github.com/gpiozero/gpiozero/discussions/1153>]
> - External Storage: Running scripts directly from a USB flash drive or

> restricted media directory often conflicts with Linux file permission

> policies. [1 <https://forums.raspberrypi.com/viewtopic.php?t=399250>, 2
> <https://forums.raspberrypi.com/viewtopic.php?t=379869>]

>
> How to Fix It
> You can easily resolve this issue using one of the following proven methods:
> Method 1: Change the Working Directory Environment Variable (Recommended) [1

> <https://github.com/joan2937/lg/issues/12>]

> You can force lgpio to create its temporary notification pipes in the
> system's global temporary folder (/tmp), where all users have write

> permissions. [1 <https://github.com/joan2937/lg/issues/22>, 2
> <https://forum.openmarine.net/showthread.php?tid=6149&page=2>]
>
> 1. Open your terminal.
> 2. Define the global environment variable by running:

> bash
> export LG_WD=/tmp
> Use code with caution.

> 3. To make this change permanent, add export LG_WD=/tmp to your system

> profile or your shell configuration file (like ~/.bashrc). [1

> <https://forum.openmarine.net/showthread.php?tid=6149&page=2>]

>
> Method 2: Fix the Systemd Service File
> If your script crashes specifically when executed via a systemd service,
> you must explicitly declare a writable directory. [1

> <https://github.com/gpiozero/gpiozero/discussions/1153>]
>
> 1. Open your service configuration file (e.g.,
> /etc/systemd/system/myscript.service).
> 2. Add a WorkingDirectory parameter under the [Service] block pointing

> to a path owned by your script's user:
> ini
> [Service] WorkingDirectory=/home/your_username/
> ExecStart=/usr/bin/python3 /home/your_username/script.py
> Use code with caution.

> 3. Reload the system daemon and restart your service:

> bash
> sudo systemctl daemon-reload sudo systemctl restart myscript.service
> Use code with caution.

> [1 <https://github.com/gpiozero/gpiozero/discussions/1153>]

>
> Method 3: Change Directory Inside the Python Script
> If you do not want to change system files, you can force the Python runtime
> to change its execution context to a writable folder before invoking any
> hardware controls. Add these lines to the absolute top of your script: [1

> <https://github.com/gpiozero/gpiozero/discussions/1153>]

>>>> *⊣GE⊢*

[Vince Skahan]

2026-07-05T11:31:26.452462+02:00 webpi weewxd[1283]: 2026-07-05 11:31:26 xCreatePipe: Can't set permissions (436) for //.lgd-nfy0, No such file or directory

Matthew and I answered this last fall in the original thread above.  For some reason your setup is trying to write to a directory the running process has no permissions to write to.

It is entirely possible the later python version contents in trixie changed something under the hood but it's hard to say. 

Personally I'd try patching as2935.py ala the instructions in https://github.com/gpiozero/gpiozero/discussions/1153 to hard-set the directory it works in.  Look at item 2 in the green solution in that thread where it says "use os.chdir() in the python program before any calls to gpizero"

Perhaps add "os.chdir(/tmp)" above the lines that say:

        # configure the gpio
        GPIO.setmode(GPIO.BCM)
        GPIO.setup(self.pin, GPIO.IN)

No harm in trying...

[Christian Peters]

Vince,

thanks for the suggestion, I tried this on several positions in the
code, but maybe not at the right position....

I did the pip install of weewx now and this error is gone, one step
forward.
But now raise a new one.

File "/home/pi/weewx-data/bin/user/as3935.py", line 188, in __init__
2026-07-06T08:00:31.468506+02:00 webpi python3[9148]:
GPIO.add_event_detect(self.pin, GPIO.RISING,
2026-07-06T08:00:31.489954+02:00 webpi python3[9148]:
~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
2026-07-06T08:00:31.493540+02:00 webpi python3[9148]:
callback=self.handle_interrupt)
2026-07-06T08:00:31.497561+02:00 webpi python3[9148]:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2026-07-06T08:00:31.509146+02:00 webpi python3[9148]: RuntimeError:
Failed to add edge detection

Maybe I have to check cabeling of the AS3935..?....let's see...

Regards,

Christian

Am 06.07.26 um 08:00 schrieb Vince Skahan: