zoio

Cross-platform (macOS / Linux / Windows) process resource monitor written in Rust.

zoio lets you pick running processes via a checkbox list or match them with regex patterns, then watches their CPU, memory, disk I/O, and network I/O in real time. All matched subprocesses are followed automatically. Metrics are drawn as four live plots (one per resource) that can be viewed per-process, combined, or grouped. When you stop the session, the full capture is exported to CSV.

Features

• Process discovery — live checkbox list of every running process (searchable by name or pid).
• Regex filters — add one or more patterns; any matching process (and optionally its child tree) is tracked.
• Per-process metrics — CPU %, resident memory, disk I/O rate, network I/O rate, sampled independently.
• Real-time plots — four separate plots (CPU / Memory / Disk / Network) rendered with egui_plot.
• View modes — Individual (one line per process), Combined (aggregate of all), Grouped (aggregate per user group).
• Groups — bundle the currently-selected PIDs into a named group and plot it as one aggregated series.
• Start / Stop — explicit session control; stopping preserves the captured data for inspection and export.
• CSV export — flat table with timestamp_ms, elapsed_secs, pid, name, parent_pid, cpu_percent, memory_bytes, disk_bytes_per_sec, net_bytes_per_sec.

Build & run

cargo run --release

Tests

# unit tests + integration tests + property tests
cargo test

# unit tests only (no child process spawning)
cargo test --lib

The integration suite under tests/ spawns real child processes (sleep on unix, cmd on Windows) and verifies that zoio can discover them, sample their metrics, and round-trip them through CSV.

Architecture

src/
├── lib.rs              # public API re-exports
├── main.rs             # eframe window bootstrap
├── app.rs              # AppState + ZoioApp (egui rendering)
├── process_monitor.rs  # sysinfo-backed discovery + sampling
├── process_filter.rs   # regex FilterSet
├── metrics.rs          # MetricKind, MetricSample, ProcessHistory
└── csv_export.rs       # CSV writer
tests/
├── monitor_flow.rs     # end-to-end: spawn → monitor → CSV
└── csv_properties.rs   # property-based CSV invariants

The core pipeline (AppState) has no egui dependency and is fully headlessly testable. The ZoioApp type wraps it with the eframe rendering layer.

Platform notes

• Per-process network counters are not uniformly exposed by sysinfo across platforms. On platforms where they are unavailable, the network series reports 0.0. Disk, CPU, and memory work everywhere sysinfo does.
• On Windows, accurate CPU sampling requires at least two refreshes; the first reported value is 0.0.