Architecture

baba is one Go binary built from the standard library only: no modules, no cgo, no runtime to install. It was a Bun app until its binaries grew too big; the Go build is about 7 MB (3 MB gzipped) per platform.

One cycle

config.json + BABA_* ──► config ──► start
                                      │ every intervalSeconds
                                      ▼
                   sysinfo readings (CPU, load, memory, disks, sensors, nvidia-smi)
                                      │
                                      ▼
                   monitor: breach counts, open / remind / resolve
                          │                               │
                          ▼                               ▼
                 incidents (JSON file)          notify (Discord, Telegram)

• config decodes config.json over the defaults, applies the BABA_* variables, then validates everything at once. Every command goes through it.
• sysinfo reads the metrics. Parsers are plain functions over text (/proc/stat, top output, nvidia-smi CSV) that compile everywhere, so their tests run on any OS; only the readers are per-OS files.
• monitor holds the breach counts and decides: open, remind, resolve. It gets the incident store and an alert function, so tests drive it with fakes.
• incidents is the history, one JSON file rewritten atomically on each change.
• notify posts to Discord and Telegram and reports every failure.

The checks run one after the other: nothing is shared between goroutines, so there are no locks. The CPU sample makes a cycle last a little over a second. The only other goroutine is the one-time update check at startup.

Decisions

• Standard library only. Every module is size and supply chain. Metrics that would need cgo or private APIs on macOS come from its command-line tools instead (top, sysctl, vm_stat, mount).
• JSON, not SQLite. A pure-Go SQLite driver costs several MB, and the history is a few hundred small records. The file is readable with jq.
• Sequential checks. A cycle every minute doesn't need parallelism, and the monitor stays lock-free.
• Release asset names. baba-<os>-<x64|arm64> comes from the Bun builds: baba update in installed binaries and the install script download those names, so they can't change.
• No Windows. Its metrics and service manager need APIs the standard library doesn't have.

Building and testing

make build   # dist/baba-<os>-<arch> and .gz, for Linux and macOS
make test    # unit tests, then integration tests on the real binary
make cover   # coverage across both; fails under 70%

Integration tests build the binary and drive it like a user: the setup wizard with piped answers, validate, then start against the real host with every threshold at 0, alerts landing in a fake Discord webhook, and the incident commands afterwards. More in CONTRIBUTING.md.