87 lines
2.4 KiB
Python
87 lines
2.4 KiB
Python
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"""示例 3：重试与超时。
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运行::
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uv run python examples/03_retry_and_timeout.py
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"""
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from __future__ import annotations
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import time
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from chongming_task.policies import ExponentialBackoff, RetryPolicy, Timeout
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from chongming_task.run import run_task
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_attempts = 0
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def flaky(ctx, succeed_on_attempt: int) -> str:
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"""前几次故意失败，用来演示重试与退避。"""
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global _attempts
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_attempts += 1
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if _attempts < succeed_on_attempt:
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raise RuntimeError(f"第 {_attempts} 次尝试遇到暂时性故障")
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return f"第 {_attempts} 次尝试成功"
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def slow(ctx) -> str:
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"""跑得很慢，用来演示超时后会被请求停止。"""
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for _ in range(10_000):
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ctx.checkpoint()
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time.sleep(0.01)
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return "跑完了"
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def demo_retry() -> None:
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print("== 重试：失败两次后成功 ==")
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_attempts = 0
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outcome = run_task(
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flaky,
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3,
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retry=RetryPolicy(max_attempts=5, backoff=ExponentialBackoff(base=0.05, factor=2)),
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task_id="demo-retry",
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name="会抖的任务",
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)
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print(f" 终态 ：{outcome.status.value}")
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print(f" 返回值 ：{outcome.value}")
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print(f" 尝试次数 ：{outcome.snapshot.attempt}/{outcome.snapshot.max_attempts}")
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def demo_retry_exhausted() -> None:
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print("\n== 重试：预算耗尽 ==")
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global _attempts
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_attempts = 0
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outcome = run_task(
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flaky,
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99, # 永远不会成功
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retry=RetryPolicy(max_attempts=2, backoff=ExponentialBackoff(base=0.05, factor=1)),
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task_id="demo-exhausted",
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name="必定失败",
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)
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print(f" 终态 ：{outcome.status.value}")
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print(f" 尝试次数 ：{outcome.snapshot.attempt}/{outcome.snapshot.max_attempts}")
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print(f" 失败归类 ：{outcome.failure.kind.value if outcome.failure else '-'}")
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def demo_timeout() -> None:
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print("\n== 超时：单次尝试不超过 0.5 秒 ==")
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outcome = run_task(
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slow,
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timeout=Timeout(per_attempt=0.5),
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task_id="demo-timeout",
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name="慢任务",
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)
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print(f" 终态 ：{outcome.status.value}")
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print(f" 失败归类 ：{outcome.failure.kind.value if outcome.failure else '-'}")
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print(f" 可重试 ：{outcome.failure.retryable if outcome.failure else '-'}")
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def main() -> None:
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demo_retry()
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demo_retry_exhausted()
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demo_timeout()
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if __name__ == "__main__":
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main()
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