How to capture rust stdout output from python

[RobertCraigie]

I've tried using pytest's capsys fixture and python's contextlib.redirect_stdout but neither seemed to capture any output.

Is capturing stdout output from python supported?

Thank you for this fantastic library!

[davidhewitt]

See #1918 (comment)

[tcztzy]

I am in a more sophisticated situation, I use autocxx to wrapper C++ codes and the stdout is come from C++ code. But I can give some suggestions for you.

You can impl the std::io::Write trait for a rust struct

use std::io::Write;
struct PySysStdout;

impl Write for PySysStdout {
    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
        let s = std::str::from_utf8(buf).unwrap();
        Python::with_gil(|py| {
            let locals = PyDict::new(py);
            locals.set_item("s", s).unwrap();
            py.run("print(s, end='')", None, Some(&locals)).unwrap();
        });
        Ok(buf.len())
    }
    fn flush(&mut self) -> std::io::Result<()> {
        Python::with_gil(|py| {
            py.run("import sys;sys.stdout.flush()", None, None).unwrap();
        });
        Ok(())
    }
}

And then, refer this StackOverflow answer.

Hope it works for you!