How to use gpiozero inside a docker container on a Pi5?

[torntrousers]

Can anyone help with using gpiozero in a docker container on a Pi5?

On a Pi4 it works by adding --device=/dev/gpiomem:/dev/gpiomem on the docker run command, but on the Pi5 there isn't a /dev/gpiomem instead there are multiple:

ls /dev/gpio*
/dev/gpiochip0  /dev/gpiochip2  /dev/gpiochip4  /dev/gpiomem1  /dev/gpiomem3
/dev/gpiochip1  /dev/gpiochip3  /dev/gpiomem0   /dev/gpiomem2  /dev/gpiomem4

I've tried using all those but nothing - sudo docker run --rm --privileged --device /dev/gpiomem0:/dev/gpiomem0 --device /dev/gpiomem1:/dev/gpiomem1 --device /dev/gpiomem2:/dev/gpiomem2 --device /dev/gpiomem3:/dev/gpiomem3 --device /dev/gpiomem4:/dev/gpiomem4 --device /dev/gpiochip0:/dev/gpiochip0 --device /dev/gpiochip1:/dev/gpiochip1 --device /dev/gpiochip2:/dev/gpiochip2 --device /dev/gpiochip3:/dev/gpiochip3 --device /dev/gpiochip4:/dev/gpiochip4 docker.io/antelder/rpiblink-ubuntu the docker runs but doesn't control the actual gpio pins.

Any suggestions?

[fruttodelmondo]

To access the 40-pin GPIO headers on the Pi 5 you only need /dev/gpiomem4.
You'll also need to workaround an issue in gpiozero. See #891
The workaround is to install gpiozero via pip. The pip version already includes a fix, while the packages in the Ubuntu repo don't. Pip refuses to install packages system-wide, so we use the --break-system-packages option to override the default behavior. A better solution would be to use a virtual environment, but I haven't tried that.
Once gpiozero 2.0 becomes available via the distros package manager below solution is obsolete.

The Dockerfile:

FROM ubuntu:23.04

RUN apt update && apt install -y python3-pip python3-lgpio python3-pigpio python3-rpi.gpio
RUN pip3 install gpiozero --break-system-packages

CMD ["python3"]

Then build and run. This will drop you into the Python REPL:

docker build -t gpiozerotest . && docker run -it --privileged --device /dev/gpiomem4:/dev/gpiomem4 gpiozerotest

Now import gpiozero and turn a LED on/off

from gpiozero import LED

led = LED(17)
while True:
    led.on()
    led.off()

On the oscilloscope I see a signal with a frequency of about 83kHz

[torntrousers]

thank you so much , that works!

is that the correct issue link for issue about the workaround?

from googling i couldn't find much about the new Pi5 gpio's - how did you know that only gpiomem4 is needed ?

just curious - does it really need all three of python3-lgpio python3-pigpio python3-rpi.gpio?

[fruttodelmondo]

I gues I was about unclear about the link. The link isn't for the workaround, but for the issue. The problem described in #891 (comment) would arise when using gpiozero < 2.0.

Libgpiod has some tools to get information about the GPIOs. It should be already installed when using the Raspberry OS.
From the libgpiod mirror on Github:

• gpiodetect - List all GPIO chips present on the system, their names, labels and number of GPIO lines.
• gpioinfo - List all lines of specified GPIO chips, their names, consumers, direction, active state and additional flags.
• gpioget - Read values of specified GPIO lines.
• gpioset - Set values of specified GPIO lines, and potentially keep the lines exported and wait until timeout, user input or signal.
• gpiofind - Find the GPIO chip name and line offset given the line name.
• gpiomon - Wait for events on GPIO lines, specifying which events to watch, how many events to process before exiting or if the events should be reported to the console.

Run gpioinfo and you'll get a long list of information. gpiochip4 is the mapping of the physical pins to the GPIO header pins. Line 17 here is equivalent with GPIO pin 17 on the header and physical pin 11. It fits the Raspberry pin mapping .

gpiochip4 - 54 lines:
[...]
	line   0:      "ID_SD"       unused   input  active-high 
	line   1:      "ID_SC"       unused   input  active-high 
	line   2:       "PIN3"       unused   input  active-high 
	line   3:       "PIN5"       unused   input  active-high 
	line   4:       "PIN7"       unused   input  active-high 
	line   5:      "PIN29"       unused   input  active-high 
	line   6:      "PIN31"       unused   input  active-high 
	line   7:      "PIN26"       unused   input  active-high 
	line   8:      "PIN24"       unused   input  active-high 
	line   9:      "PIN21"       unused   input  active-high 
	line  10:      "PIN19"       unused   input  active-high 
	line  11:      "PIN23"       unused   input  active-high 
	line  12:      "PIN32"       unused   input  active-high 
	line  13:      "PIN33"       unused   input  active-high 
	line  14:       "PIN8"       unused   input  active-high 
	line  15:      "PIN10"       unused   input  active-high 
	line  16:      "PIN36"       unused   input  active-high 
        line  17:      "PIN11"       unused  output  active-high
	line  18:      "PIN12"       unused   input  active-high 
	line  19:      "PIN35"       unused   input  active-high 
	line  20:      "PIN38"       unused   input  active-high 
	line  21:      "PIN40"       unused   input  active-high 
	line  22:      "PIN15"       unused   input  active-high 
	line  23:      "PIN16"       unused   input  active-high 
	line  24:      "PIN18"       unused   input  active-high 
	line  25:      "PIN22"       unused   input  active-high 
	line  26:      "PIN37"       unused   input  active-high 
	line  27:      "PIN13"       unused   input  active-high 
	line  28: "PCIE_RP1_WAKE" unused input active-high 
	line  29:   "FAN_TACH"       unused   input  active-high 
	line  30:   "HOST_SDA"       unused   input  active-high 
	line  31:   "HOST_SCL"       unused   input  active-high 
	line  32:  "ETH_RST_N"  "phy-reset"  output   active-low [used]
	line  33:          "-"       unused   input  active-high 
	line  34: "CD0_IO0_MICCLK" "cam0_reg" output active-high [used]
	line  35: "CD0_IO0_MICDAT0" unused input active-high 
	line  36: "RP1_PCIE_CLKREQ_N" unused input active-high 
	line  37:          "-"       unused   input  active-high 
	line  38:    "CD0_SDA"       unused   input  active-high 
	line  39:    "CD0_SCL"       unused   input  active-high 
	line  40:    "CD1_SDA"       unused   input  active-high 
	line  41:    "CD1_SCL"       unused   input  active-high 
	line  42: "USB_VBUS_EN" unused output active-high 
	line  43:   "USB_OC_N"       unused   input  active-high 
	line  44: "RP1_STAT_LED" "PWR" output active-low [used]
	line  45:    "FAN_PWM"       unused  output  active-high 
	line  46: "CD1_IO0_MICCLK" "cam1_reg" output active-high [used]
	line  47:  "2712_WAKE"       unused   input  active-high 
	line  48: "CD1_IO1_MICDAT1" unused input active-high 
	line  49: "EN_MAX_USB_CUR" unused output active-high 
	line  50:          "-"       unused   input  active-high 
	line  51:          "-"       unused   input  active-high 
	line  52:          "-"       unused   input  active-high 
	line  53:          "-"       unused   input  active-high 

It doesn't need all three of python3-lgpio python3-pigpio python3-rpi.gpio. Using just python3-lgpio works and seems to be switching about 10k faster. I have no clue why that is.

[torntrousers]

Sounds great, can you share your code please? I can't get it to work with code from the example here - https://www.acmesystems.it/libgpiod

[fruttodelmondo]

I changed the Dockerfileto include installation of python3-libgpiod and a second Python script:

FROM ubuntu:23.04

RUN apt update && apt install -y python3-pip python3-lgpio python3-libgpiod
RUN pip3 install gpiozero --break-system-packages


COPY "./test.py" "/test.py"
COPY "./gpiod-test.py" "/gpiod-test.py"

CMD ["python3", "gpiod-test.py"]

gpiod-test.py looks like this:

import gpiod


LED_PIN = 17

chip = gpiod.Chip('gpiochip4')
led_line = chip.get_line(LED_PIN)
led_line.request(consumer="LED", type=gpiod.LINE_REQ_DIR_OUT)

try:
   while True:
       led_line.set_value(1)
       led_line.set_value(0)
finally:
   led_line.release()

Then rebuild and run:

docker build -t gpiozerotest . && docker run -d --device /dev/gpiochip4:/dev/gpiochip4 gpiozerotest

Note that I have added my user to the dockergroup, so I don't have to prepend the commands withsudo.

# Create docker group (should already exist)
sudo groupadd docker

# Add user to docker group
sudo usermod -aG docker $USER

# Log in to new group (alternatively restart the Pi)
newgrp docker

[torntrousers]

Hello, yes that works and no more warnings so thats great, thanks.
Two things:

• on Pi4 and Pi Zero its gpiochip0 it has to use, so i need to make two docker's one for Pi5 and the other for Pi4/PiZero. It would be nice if there was some way to have just a single docker that worked out gpiochip0 or gpiochip4 itself
• the ubuntu image is really big, i've tried a smaller debian one but can't get it to work. any iedas for how to get a really small image?

Thanks again for all your help with this!

[fruttodelmondo]

Hi,
I haven't succeeded in making it work with gpiozero on Debian or Alpine yet. With those images it is the BadPinFactory error again. It works for both with gpiod, though.

For Debian and gpiod I made a gist https://gist.github.com/fruttodelmondo/72ffae3998a2092d299c886148813079

For Alpine and gpiod you can use:
Dockerfile:

FROM alpine:latest

RUN apk update && apk add python3 py3-libgpiod py3-pip

COPY "./gpiod-test.py" "/gpiod-test.py"

CMD ["python3", "gpiod-test.py"]

gpiod-test.py is the same as before:

import gpiod


LED_PIN = 17

chip = gpiod.Chip('gpiochip4')
led_line = chip.get_line(LED_PIN)
led_line.request(consumer="LED", type=gpiod.LINE_REQ_DIR_OUT)

try:
   while True:
       led_line.set_value(1)
       led_line.set_value(0)
finally:
   led_line.release()

[torntrousers]

Thanks great. The Alpine one especially is nice and small.