kantoku

0.18.3 verified Mon Apr 27 auth: no python

A process manager built on top of Circus for running and monitoring multiple processes and sockets. Current version 0.18.3, actively maintained with recent updates for Python 3.13 support and reliability fixes.

pip install kantoku

Common errors

error ModuleNotFoundError: No module named 'circus' ↓

cause circus is a required dependency but not installed automatically? It is bundled, but some installations may fail if circus is missing.

fix

Run pip install circus to ensure circus is installed.

error AttributeError: module 'kantoku' has no attribute 'Arbiter' ↓

cause Importing from the wrong module level.

fix

Use from kantoku import Arbiter instead of import kantoku; kantoku.Arbiter.

Warnings

breaking In version 0.18.0, the arbitter's quit_on_failure behavior changed to quit when any watcher fails. Previous versions allowed continued operation. ↓

fix Upgrade to >=0.18.2 or set `quit_on_failure=False` on the Arbiter.

gotcha Watcher commands are run as shell commands (via subprocess). Ensure proper quoting and escaping to avoid injection or argument parsing issues. ↓

fix Use lists or shlex.quote() for commands with arguments, e.g., cmd=['python', '-m', 'http.server', '8000'] instead of a string.

Imports

Arbiter
wrong
```
from circus import Arbiter
```
correct
```
from kantoku import Arbiter
```
kantoku wraps Circus's Arbiter; importing directly from circus bypasses kantoku's extensions.
Watcher
wrong
```
from circus import Watcher
```
correct
```
from kantoku import Watcher
```
Use kantoku's Watcher for compatibility with kantoku's lifecycle management.

Quickstart

Create a simple watcher and start the arbiter. Replace cmd with your own command.

from kantoku import Arbiter, Watcher

watcher = Watcher(
    name="my_app",
    cmd="python -m http.server 8000",
    numprocesses=1,
)

arbiter = Arbiter(
    watchers=[watcher],
)
arbiter.start()