Running in the background

lightmime run syncs without a window or tray. It waits for a command from Home Assistant, or starts right away with --start, and stops on Ctrl-C or SIGTERM, releasing the area on the bridge.

lightmime run            # wait for Home Assistant (needs [mqtt] enabled)
lightmime run --start    # sync until stopped

It still captures the screen, so it has to run inside your graphical session: the screen-cast portal belongs to the session, and the first start shows its screen picker. After that the choice is remembered and later starts are silent, which is what makes running at login work.

For a tray icon at login rather than a headless service, use Start at login in the window instead.

As a systemd user service

The unit in contrib/lightmime.service starts with your graphical session and restarts after a failure.

For a binary or source install in ~/.local/bin:

install -Dm644 contrib/lightmime.service ~/.config/systemd/user/lightmime.service
systemctl --user daemon-reload
systemctl --user enable --now lightmime

For the Flatpak, write the unit with the Flatpak’s command instead:

# ~/.config/systemd/user/lightmime.service
[Unit]
Description=lightmime: Hue screen sync
PartOf=graphical-session.target
After=graphical-session.target

[Service]
ExecStart=/usr/bin/flatpak run --command=lightmime io.github.pataar.lightmime run
Restart=on-failure
RestartSec=5

[Install]
WantedBy=graphical-session.target

Run lightmime run --start once by hand first, so you can answer the screen picker.

Follow the log with journalctl --user -u lightmime -f. Set Environment=RUST_LOG=debug in the [Service] section for more detail.

Run either the service or the window, not both: only one of them can stream to the area.