[BUG] Docker in limbo after serial interruption

[madejackson]

So I am trying to use mbusd inside a docker container on a rpi4. So far it works perfectly fine apart from one issue:

When the connection to the serial port gets interrupted, the process stops working / stops accepting connection from modbusTCP-clients.

For my testing I used home assistant which underlying uses pymodbus to connect to mbusd in a seperate container.

mbusd thinks it reconnects successfully, but because the device link to the host is broken, only a restart of the container actually fixes it.

Example log from container when the serialport-connection gets interrupted:

2024-08-14 09:32:24
14 Aug 2024 09:32:24 tty: error in read() (port closed)
2024-08-14 09:32:24
14 Aug 2024 09:32:24 tty: trying to open /dev/ttyModbus (speed 9600 mode 8N1)
2024-08-14 09:32:24
14 Aug 2024 09:32:24 tty_reopen(): can't open tty device /dev/ttyModbus (No such device or address)
2024-08-14 09:32:24
14 Aug 2024 09:32:24 tty: trying to open /dev/ttyModbus (speed 9600 mode 8N1)
2024-08-14 09:32:24
14 Aug 2024 09:32:24 tty_reopen(): can't open tty device /dev/ttyModbus (No such device or address)
2024-08-14 09:32:24
14 Aug 2024 09:32:24 tty: trying to open /dev/ttyModbus (speed 9600 mode 8N1)
2024-08-14 09:32:24
14 Aug 2024 09:32:24 tty_reopen(): can't open tty device /dev/ttyModbus (No such device or address)
2024-08-14 09:32:25
14 Aug 2024 09:32:25 tty: trying to open /dev/ttyModbus (speed 9600 mode 8N1)

corresponding logs from host, when the serialports lose connection and reconnect:

Aug 14 09:32:24 xxxx kernel: usb 1-1.3: USB disconnect, device number 7
Aug 14 09:32:24 xxxx kernel: usb 1-1.3: new full-speed USB device number 8 using xhci_hcd
Aug 14 09:32:24 xxxx kernel: usb 1-1.3: New USB device found, idVendor=xxxx, idProduct=xxxx, bcdDevice= 2.00
Aug 14 09:32:24 xxxx kernel: usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Aug 14 09:32:24 xxxx kernel: usb 1-1.3: Product: xxx
Aug 14 09:32:24 xxxx kernel: usb 1-1.3: Manufacturer: xxx
Aug 14 09:32:24 xxxx kernel: usb 1-1.3: SerialNumber: xxx
Aug 14 09:32:24 xxxx kernel: cdc_acm 1-1.3:1.0: ttyACM0: USB ACM device
Aug 14 09:32:24 xxxx kernel: cdc_acm 1-1.3:1.2: ttyACM1: USB ACM device
Aug 14 09:32:24 xxxx kernel: cdc_acm 1-1.3:1.4: ttyACM2: USB ACM device
Aug 14 09:32:24 xxxx kernel: cdc_acm 1-1.3:1.6: ttyACM3: USB ACM device

I think I try to do an new docker image with healthchecking via pymodbus and do a restart when the serialport gets broken.