Celery 작업의 실행 시간을 어떻게 측정합니까?

<code class="language-python">from celery import signals
from dateutil.parser import isoparse
from datetime import datetime, timezone

@signals.before_task_publish.connect
def before_task_publish(*, headers: dict, **kwargs):
    raw_eta = headers.get("eta")
    publish_time = isoparse(raw_eta) if raw_eta else datetime.now(tz=timezone.utc)
    headers["__publish_time"] = publish_time.isoformat()</code>

<code class="language-python">from celery import signals
from datetime import datetime, timezone

@signals.task_prerun.connect
def task_prerun(*, task: Task, **kwargs):
    setattr(task.request, "__prerun_time", datetime.now(tz=timezone.utc).isoformat())</code>

<code class="language-python">from celery import signals, Task
from dateutil.parser import isoparse
from datetime import datetime, timezone, timedelta

def to_milliseconds(td: timedelta) -> int:
    return int(td.total_seconds() * 1000)

@signals.task_postrun.connect
def task_postrun(*, task: Task, **kwargs):
    now = datetime.now(tz=timezone.utc)
    publish_time = isoparse(getattr(task.request, "__publish_time", ""))
    prerun_time = isoparse(getattr(task.request, "__prerun_time", ""))

    exec_time = now - prerun_time if prerun_time else timedelta(0)
    waiting_time = prerun_time - publish_time if publish_time and prerun_time else timedelta(0)
    waiting_and_exec_time = now - publish_time if publish_time else timedelta(0)

    stats = {
        "exec_time_ms": to_milliseconds(exec_time),
        "waiting_time_ms": to_milliseconds(waiting_time),
        "waiting_and_exec_time_ms": to_milliseconds(waiting_and_exec_time),
    }
    # TODO: 将统计数据发送到 StatsD 或其他监控工具
    statsd.timing(f"celery.task.exec_time_ms", stats["exec_time_ms"], tags=[f"task:{task.name}"])
    # ... 发送其他统计数据 ...</code>

<code class="language-python">if exec_time > timedelta(hours=1):
    logger.error(f"任务 {task.name} 执行时间过长: {exec_time}。请检查！")</code>