Resource Monitor TUI (macOS)

A lightweight, terminal‑based resource dashboard written in Rust + [Ratatui]
that works un‑privileged on contemporary macOS (Monterey → Sonoma).

┌ CPU % ────────────────┐
│██████████▌  56 %      │
└───────────────────────┘
┌ Last 60 s ────────────┐
│▁▂▂▃▄▅▇█▇▅▄▃▂▁         │
└───────────────────────┘
┌ MEM 6123 / 16384 MiB ┐
│██████▏ 37 %          │
└──────────────────────┘
┌ SSD 118 / 512 GiB ───┐
│███▎ 23 %             │
└──────────────────────┘
┌ FDs open: 152 ┐
└───────────────┘
┌ Disk Δ  R  24 KB  W  8 KB ┐
└───────────────────────────┘
┌ 🔋 86 % discharging – 2 h 44 m ┐
└────────────────────────────────┘

(press q to quit)

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Features

Widget	Data Source	Refresh
CPU gauge & 60 s sparkline	sysinfo	0.5 s
Memory gauge	sysinfo	0.5 s
Disk‑usage gauge (root fs)	statfs	5 s (same tick)
FD count	/dev/fd	0.5 s
Disk I/O deltas	proc_pid_rusage	0.5 s
Battery paragraph	pmset -g batt	30 s (polled every tick)

Colour threshold: Green < 50 %, Yellow 50 – 80 %, Red > 80 %.

No root, no entitlements required.

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Build & Run

# Requires Rust ≥ 1.70 and a macOS tool‑chain
git clone <your fork>
cd resource-monitor
cargo run --release      # q to quit

Optional: build an optimised binary

cargo build --release
./target/release/resource-monitor

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Controls

Key	Action
q	Quit the monitor

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Internals

• Ratatui renders the TUI.
• Crossterm handles raw‑mode and key events.
• Metrics are gathered in monitor/:
  • cpu.rs – system‑wide utilisation
  • memory.rs – RSS / total
  • disk.rs – root filesystem usage
  • io.rs – per‑process disk I/O
  • fd.rs – open file‑descriptors
  • battery.rs – wraps pmset
• monitor::Monitor produces a Snapshot; ui.rs draws it.

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Tested On

• macOS 14 Sonoma (Apple M1)
• macOS 13 Ventura (Intel)

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License

MIT