USB automator

This little utility can run commands when a device is plugged or unplugged.

The main use case is to change keyboard layout according to device presence. It can also be used to start a backup when your external drive is plugged.

Configuration

On first run a default config file will be created in $XDG_CONFIG_HOME/usbautomator/config.toml. Configuration follows this pattern:

[devices.NAME]
on_plugged = "COMMAND"
on_unplugged = "COMMAND"
[devices.NAME.properties]
ID_VENDOR_ID = "feed"
ID_MODEL_ID = "1307"
ID_INPUT_KEYBOARD = "1"
KEY = "1000000000007 ff9f207ac14057ff febeffdfffefffff fffffffffffffffe"

How to configure an automation ?

Let's say you want to switch layout when your keyboard is plugged. We will configure usbautomator step by step.

First, add a section with your commands:

[devices.mykeyboard]
on_plugged = "setxkbmap us"
on_unplugged = "setxkbmap <your laptop layout or whatever>"

You then need to find some properties which uniquely identify your device. Warning: a single physical device might show up as several devices on your operating system.

You can use the watch command:

usbautomator -w

This will listen for changes and display the properties of the devices (there might be a lot of them). Simply plug your keyboard to list changed devices properties. The command can be killed as usual with <ctrl-c>.

You should see this kind of properties:

ID_FOR_SEAT: input-pci-0000_00_14_0-usb-0_1_1_3
ID_INPUT: 1
ID_INPUT_KEY: 1
ID_INPUT_KEYBOARD: 1
ID_MODEL: ErgoDox_EZ
[...]
ID_MODEL_ID: 1307
ID_VENDOR: ErgoDox_EZ
ID_VENDOR_ID: feed
KEY: 1000000000007 ff9f007ac04007ff febeffdfffefffff fffffffffffffffe
NAME: "ErgoDox EZ ErgoDox EZ"
PRODUCT: 3/feed/1307/111

Some properties depend on the USB bus, those are not useful to identify your device as they might change depending on the USB plug used to connect your device. The KEY property seems a good fit to identify your device, let's add it to the configuration:

[devices.mykeyboard.properties]
KEY = "1000000000007 ff9f007ac04007ff febeffdfffefffff fffffffffffffffe"

Your keyboard layout should now change according to the device presence.

Note: if the properties used in the configuration match multiple devices, the on_plugged/on_unplugged commands will run multiple time.

Building

You will need rust (v1.31) and cargo.

Then simply run:

cargo build --release

Packages

Archlinux

Changelog

See CHANGELOG.md

License

GPLv3