bot-chassis

The boring 90% of every bot, done for you.

pip install bot-chassis

Anyone who has run a long-lived automation — a trading bot, an uptime monitor, a scraper, a report generator — ends up rebuilding the same plumbing: a scheduler loop, crash handling, restart logic, a way to know it's hung (not just dead), alerts to your phone, a kill switch, state that survives crashes, and a second process watching the first one. That plumbing is where the failures actually happen, and it has nothing to do with your domain.

chassis is that plumbing as a product. You write the 10% that's yours; it runs it like production infrastructure. Zero dependencies — pure Python stdlib, 3.11+.

A complete bot

from chassis import Bot

bot = Bot("uptime", log_file="uptime.log")

@bot.every(minutes=5)
def check():
    if not site_is_up("https://example.com"):
        bot.alert("DOWN: example.com")

bot.run()

That function now has, for free:

A supervised fleet

Declare bots once in bots.toml:

[chassis]
alerts = ["sms", "console"]
digest_at = "16:35"                # daily summary text

[[bot]]
name = "uptime"
command = "python3 uptime_bot.py"
heartbeat_max_minutes = 10
log = "uptime.log"

Then:

chassis run     # spawn everything; restart crashes; give up on crash-loops; alert on hangs
chassis watch   # independent watchdog — still texts you when the supervisor itself dies
chassis dash    # mission control: http://localhost:8899 status page (+ /api/status JSON)
chassis init    # starter bots.toml + hello bot

(python -m chassis works everywhere the chassis script does.)

The supervisor restarts bots that die (with rapid-crash backoff so a broken bot doesn't restart forever) and alerts on stale heartbeats. The watchdog runs as a separate process and re-checks everything from outside — processes, heartbeats, kill switch, error spikes in logs — with per-issue alert cooldowns and an optional daily digest and healthchecks.io ping. Domain checks plug in:

wd = Watchdog(load("bots.toml"))

@wd.add_check
def account_equity():   # anything that returns [(key, message)]
    ...

Troubleshooting

Every HTTPS request fails instantly with CERTIFICATE_VERIFY_FAILED (bot jobs, the sms/webhook channels): your Python has no CA certificate bundle — common with python.org installers on macOS. Either run the installer's Install Certificates.command, or point Python at the system bundle:

export SSL_CERT_FILE=/etc/ssl/cert.pem

Provenance

Extracted from a live multi-bot trading system where every one of these features was added because its absence caused a real incident: a bot that ran dead for a day with no alert (supervision), a hung process that passed the liveness poll (heartbeats), burst SMS silently collapsed by the carrier (delivery slots), a crash mid-write corrupting state (atomic saves), a launcher that couldn't report its own death (external watchdog). That trading fleet runs on bot-chassis today — this package is its production supervisor, not a side project's abstraction of one.

Linux and macOS. Python 3.11+. Zero dependencies, and that's a promise, not a current status.

Layout

chassis/
  runner.py       Bot — the decorator API and job loop
  supervisor.py   fleet spawn/restart/heartbeat supervision
  watchdog.py     independent external health monitor
  dashboard.py    one-file status page + JSON API (localhost only)
  notify.py       alert fan-out: console / sms / webhook
  state.py        crash-safe JSON state
  config.py       bots.toml loader
examples/
  uptime_bot.py   a complete non-trading bot in ~40 lines

License

MIT.