RECIPES.md

Recipes

Console + rotating file, JSON to file only

setup uses one formatter for all handlers. To split formats, construct handlers manually:

import logging
import sys
from logging.handlers import RotatingFileHandler
from codechu_log._format import JsonFormatter, TextFormatter, RedactionFilter

log = logging.getLogger("myapp")
log.setLevel("INFO")

console = logging.StreamHandler(sys.stderr)
console.setFormatter(TextFormatter())
log.addHandler(console)

fh = RotatingFileHandler("app.log", maxBytes=10_000_000, backupCount=5)
fh.setFormatter(JsonFormatter())
fh.addFilter(RedactionFilter(["password", "token"]))
log.addHandler(fh)

Web request scope

from codechu_log import Context, bind, setup

log = bind(setup("api", file="api.log", json=True), service="api")

async def handle(request):
    with Context(request_id=request.headers["x-request-id"]):
        log.info("received", path=request.path)
        return await dispatch(request)

Context is contextvars-backed — concurrent requests do not see each other's fields.

Per-task logger via bind

worker_log = bind(log, worker_id=worker_id)
worker_log.info("started")
worker_log.info("job", job_id=job_id)

Logging exceptions

try:
    risky()
except Exception:
    log.exception("risky failed", op="risky")

exception sets exc_info=True automatically; the formatted traceback ends up in the exc_info JSON field.