Add Serial Number to Avahi Service for Board Deduplication

[mirkoCrobu]

Motivation

A board connected via both USB and Network currently shows up as two separate devices in the board list. This makes it difficult for a client application to know it is the same physical board.

We need a way to "deduplicate" these entries by providing a common identifier, allowing the client to show just one entry for that board.

Change description

A simple approach is to add the board's serial number to its Avahi service file. This change will be made at runtime when the EnableNetworkMode function is executed.

Specifically, we will add a new containing the serial number (e.g., serial_number=YOUR_SERIAL) to the board's .service file.

Additional Notes

Reviewer checklist

• PR addresses a single concern.
• PR title and description are properly filled.
• Changes will be merged in main.
• Changes are covered by tests.
• Logging is meaningful in case of troubleshooting.

[lucarin91]

I didn't figure out that we needed to add another sudoers file for this feature, which I would avoid to do it. So I think we should change the approach here, and we could instead do that in a systemd unit that is triggered only on the first boot, e.g., https://github.com/arduino/arduino-app-cli/blob/main/debian/arduino-app-cli/etc/systemd/system/arduino-burn-bootloader.service.
The Serial number of the board should not change, so we can do it just the first time you flash the board, and in there, you have all the permission to patch the Avahi service.

[mirkoCrobu]

How to test it

1. Create the .deb and push it into the board
   On the board
2. Be sure that /etc/avahi/services/arduino.service doesn't contain the serial number
3. Reboot the board
4. Check /etc/avahi/services/arduino.service: now you should see the serial number
5. Check that the .flag file exists: ls -l /var/lib/arduino/avahi_serial_configured.flag
6. Check the service status (should be active (exited)): systemctl status arduino-avahi-serial.service
7. Enable network mode: arduino-app-cli system network-mode enable
   From your PC
8. Check the board list configs(you should the network information with serial number:
   ): arduino-cli board list --json

[lucarin91]

I would do it before not after

[mirkoCrobu]

I put it "after" to ensure I could find the file "/etc/avahi/services/arduino.service".
Also, we don't need to restart Avahi after modifying the file.
(Btw I change it in "Before")

[lucarin91]

I put it "after" to ensure I could find the file "/etc/avahi/services/arduino.service".

The file should be always there

Also, we don't need to restart Avahi after modifying the file.

Not sure about that I think it need a restart

[dido18]

Is the .service suffix needed ?

Suggested change

	systemctl enable arduino-avahi-serial.service
	systemctl enable arduino-avahi-serial

[lucarin91]

I would also add the disable command in postrm as for the other services

[lucarin91]

I think this script should and could fail. If there is an issue, I would prefer that it start the next time instead of never

[lucarin91]

Suggested change

	echo "Warning: Serial number path not found at $SERIAL_NUMBER_PATH. Skipping." >&2
	exit 0
	echo "Warning: Serial number path not found at $SERIAL_NUMBER_PATH" >&2
	exit 1

[lucarin91]

Suggested change

	echo "Warning: Target file $TARGET_FILE not found or not writable. Skipping." >&2
	exit 0
	echo "Warning: Target file $TARGET_FILE not found or not writable." >&2
	exit 1

[lucarin91]

Suggested change

	echo "Warning: Serial number file is empty. Skipping." >&2
	exit 0
	echo "Warning: Serial number file is empty." >&2
	exit 1

[lucarin91]

Suggested change

	echo "Serial number ($SERIAL_NUMBER) already configured. Skipping."
	exit 0
	echo "Serial number ($SERIAL_NUMBER) already configured."
	exit 1

[lucarin91]

The serial number on the unoq is just a number I don't think you need to escape anything

[lucarin91]

Suggested change

exit 0

[lucarin91]

nit

Suggested change

	systemctl enable arduino-avahi-serial.service
	systemctl enable arduino-avahi-serial