Input audio device manager

🎙️ Switch your default PulseAudio input device with a single click from the GNOME / KDE / Cinnamon system tray. Now powered by a small Rust backend and a Rust tray frontend — same UX as the original Python applet, but ~10× lighter on memory and CPU.

Architecture

input-audio-monitord  →  HTTP+SSE daemon, wraps `pactl`        (port 9127)
input-audio-monitor-tray  →  Linux system tray (ksni / SNI)    (consumes the daemon)

The split is the same one used in gpu_monitor: a long-running backend that samples PulseAudio once a second, and a thin tray that subscribes to its SSE stream. A future remote frontend (web / mobile) can talk to the same HTTP API — see docs/api.md.

If you also want CPU / RAM / disk / GPU monitors in the same tray, the sibling repos follow the same pattern with different ports.

Installation

1. Prerequisites (Ubuntu / Debian)

sudo apt install pulseaudio-utils    # provides `pactl`
# Rust stable (rustup will install the toolchain pinned by rust-toolchain.toml)
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

On GNOME the AppIndicator and KStatusNotifierItem Support extension is required to render SNI tray icons.

2. Clone & build

git clone https://github.com/maximofn/input_audio_device.git
cd input_audio_device
cargo build --release --workspace

3. Install

./packaging/install.sh

Installs:

• ~/.local/bin/input-audio-monitord and ~/.local/bin/input-audio-monitor-tray
• ~/.local/share/input-audio-monitor/microphone.png
• ~/.config/systemd/user/input-audio-monitord.service (enabled + started)
• ~/.config/autostart/input-audio-monitor-tray.desktop

The tray will auto-start on next login. To start it now without logging out:

nohup ~/.local/bin/input-audio-monitor-tray >/dev/null 2>&1 & disown

4. Migrating from the legacy Python applet

The Python script (legacy/input_audio_device.py) and its install helpers are kept under legacy/ for reference until the Rust version has been running clean for a release cycle. If the old autostart entry is still around from a previous install, remove it:

rm -f ~/.config/autostart/input_audio_device.sh.desktop

Manual usage (without installing)

# Backend on its own — useful for hacking on the API
cargo run -p input-audio-monitord -- --port 9127

# Tray pointing at the running backend
cargo run -p input-audio-monitor-tray -- --backend-url http://127.0.0.1:9127

# Backend without real PulseAudio (CI, containers)
cargo run -p input-audio-monitord -- --mock

CLI flags

input-audio-monitord:

flag	env var	default
--bind	INPUT_AUDIO_MONITORD_BIND	127.0.0.1
--port	INPUT_AUDIO_MONITORD_PORT	9127
--sample-interval-ms	INPUT_AUDIO_MONITORD_SAMPLE_INTERVAL_MS	1000
--mock	INPUT_AUDIO_MONITORD_MOCK	false
--log-level	RUST_LOG	info

input-audio-monitor-tray:

flag	env var	default
--backend-url	INPUT_AUDIO_MONITOR_TRAY_URL	http://127.0.0.1:9127
--hide-monitors	INPUT_AUDIO_MONITOR_TRAY_HIDE_MONITORS	false
--log-level	RUST_LOG	info

--hide-monitors filters out PulseAudio *.monitor sources (which capture the output of a sink) from the menu.

Updating after a rebuild

The daemon is a systemd user unit; reload it with:

cargo build --release --workspace
install -m 0755 target/release/input-audio-monitord ~/.local/bin/
systemctl --user restart input-audio-monitord

The tray is not a systemd unit (it needs the graphical session). Replace the binary and respawn it manually:

install -m 0755 target/release/input-audio-monitor-tray ~/.local/bin/
pkill -f "$HOME/.local/bin/input-audio-monitor-tray$"
nohup ~/.local/bin/input-audio-monitor-tray >/dev/null 2>&1 & disown

(Do not use pkill -x input-audio-monitor-tray — the kernel truncates comm to 15 chars and the binary name is 24, so the exact match misses.)

Sibling monitors

Same architecture, different resource:

• gpu_monitor — NVIDIA GPU temperature / memory / processes (port 9123)
• cpu_monitor, ram_monitor, disk_monitor — planned (ports 9124 / 9125 / 9126)

Support

If this is useful to you, a ☆ Star is appreciated.