Python的键盘中断不会中止Rust函数（PyO3）

Question

我有一个用PyO3编写的Python库，它涉及一些昂贵的计算（单个函数调用最多10分钟）。从Python调用时如何中止执行

Ctrl+C似乎只在执行结束后处理，因此基本上是无用的

最小可复制示例：

# Cargo.toml

[package]
name = "wait"
version = "0.0.0"
authors = []
edition = "2018"

[lib]
name = "wait"
crate-type = ["cdylib"]

[dependencies.pyo3]
version = "0.10.1"
features = ["extension-module"]

// src/lib.rs

use pyo3::wrap_pyfunction;

#[pyfunction]
pub fn sleep() {
    std::thread::sleep(std::time::Duration::from_millis(10000));
}

#[pymodule]
fn wait(_py: Python, m: &PyModule) -> PyResult<()> {
    m.add_wrapped(wrap_pyfunction!(sleep))
}

$ rustup override set nightly
$ cargo build --release
$ cp target/release/libwait.so wait.so
$ python3
>>> import wait
>>> wait.sleep()

输入wait.sleep()后，我立即键入Ctrl + C，字符^C被打印到屏幕上，但仅10秒后，我最终获得

>>> wait.sleep()
^CTraceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyboardInterrupt
>>>

已检测到KeyboardInterrupt，但在调用Rust函数结束之前未进行处理。有没有办法绕过这个问题

当Python代码放在文件中并从REPL外部执行时，行为是相同的

Answer 1

一种选择是生成一个单独的进程来运行Rust函数。在子进程中，我们可以设置一个信号处理程序，在中断时退出进程。Python将能够根据需要引发键盘中断异常。下面是一个如何执行此操作的示例：

// src/lib.rs
use pyo3::prelude::*;
use pyo3::wrap_pyfunction;
use ctrlc;

#[pyfunction]
pub fn sleep() {
    ctrlc::set_handler(|| std::process::exit(2)).unwrap();
    std::thread::sleep(std::time::Duration::from_millis(10000));
}

#[pymodule]
fn wait(_py: Python, m: &PyModule) -> PyResult<()> {
    m.add_wrapped(wrap_pyfunction!(sleep))
}

# wait.py
import wait
import multiprocessing as mp

def f():
    wait.sleep()

p = mp.Process(target=f)
p.start()
p.join()
print("Done")

以下是我在按下CTRL-C键后在机器上得到的输出：

$ python3 wait.py
^CTraceback (most recent call last):
  File "wait.py", line 9, in <module>
    p.join()
  File "/home/kerby/miniconda3/lib/python3.7/multiprocessing/process.py", line 140, in join
    res = self._popen.wait(timeout)
  File "/home/kerby/miniconda3/lib/python3.7/multiprocessing/popen_fork.py", line 48, in wait
    return self.poll(os.WNOHANG if timeout == 0.0 else 0)
  File "/home/kerby/miniconda3/lib/python3.7/multiprocessing/popen_fork.py", line 28, in poll
    pid, sts = os.waitpid(self.pid, flag)
KeyboardInterrupt