flokli / display-agent

export connected outputs and allow controlling what's shown there via mqtt. Used for wip.bar at bornhack.

display-agent

Daemon useful to manage orientation, resolution and payload of one or multiple screens over MQTT.

Run

Run go run . to build and run the project.

The following environment variables need to be set:

• MQTT_SERVER_URL needs to point to an MQTT server (for example test.mosquitto.org:1883)
• MQTT_TOPIC_PREFIX needs to specify a non-empty topic prefix to publish into (for example bornhack/2023/wip.bar)

MQTT Topics

For each connected output, the server (periodically) publishes to the following topics:

• $topicPrefix/$outputName@$machineID/state contains the current configuration (display layout, currently active scenario).
• $topicPrefix/$outputName@$machineID/info Info contains more general information about the connected display (make, model, serial, supported modes).

Check outputs/type.go for an exhaustive list of the fields.

They're published JSON-encoded.

The server listens on the following topics:

• $topicPrefix/$outputName@$machineID/set

If a message is published to that topic, it is parsed as a (sparse) state, containing all fields that should be updated in the current state.

Backends

The server currently only supports Sway as a backend, by invoking swaymsg.

PRs for other backends welcome! In case you're stuck with X, adding support for i3 should probably be easiest (as the JSON i3-msg can emit should be fairly similar).