34 lines
1.3 KiB
Python

from __future__ import annotations
import logging
from contextvars import ContextVar
consume_task_id: ContextVar[str] = ContextVar("consume_task_id", default="")
class ConsumeTaskFormatter(logging.Formatter):
"""
Logging formatter that prepends a short task correlation ID to messages
emitted during document consumption.
The ID is the first 8 characters of the Celery task UUID, set via the
``consume_task_id`` ContextVar at the entry of ``consume_file``. When
the ContextVar is empty (any log outside a consume task) no prefix is
added and the output is identical to the standard verbose format.
"""
def __init__(self) -> None:
super().__init__(
fmt="[{asctime}] [{levelname}] [{name}] {task_prefix}{message}",
style="{",
validate=False, # {task_prefix} is not a standard LogRecord attribute, so Python's
# init-time format-string validation would raise ValueError without
# this. Runtime safety comes from format() always setting
# record.task_prefix before calling super().format().
)
def format(self, record: logging.LogRecord) -> str:
task_id = consume_task_id.get()
record.task_prefix = f"[{task_id}] " if task_id else ""
return super().format(record)