this is my code:

def enqueue_output(file, queue):
    for line in iter(file.readline, ''):
        queue.put(line)
    file.close()


def read_popen_pipes(p):

    with ThreadPoolExecutor(2) as pool:
        q_stdout, q_stderr = Queue(), Queue()

        pool.submit(enqueue_output, p.stdout, q_stdout)
        pool.submit(enqueue_output, p.stderr, q_stderr)

        while True:

            if p.poll() is not None and q_stdout.empty() and q_stderr.empty():
                break

            out_line = err_line = ''

            try:
                out_line = q_stdout.get_nowait()
            except Empty:
                pass
            try:
                err_line = q_stderr.get_nowait()
            except Empty:
                pass

            yield (out_line, err_line)

def handle_base():
    try:
        with subprocess.Popen(
            ['conda', 'run', '-n', 'information_security', 'python', '/data/lkl/front/snn_assess/resnet18.py'],
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE, 
            text=True
        ) as process:

            for out_line, err_line in read_popen_pipes(process):
                if(out_line != ''):
                    socketio.emit('task_output', {'output': out_line.strip()})
                # Do stuff with each line, e.g.:
                print(out_line, end='')
                print(err_line, end='')

            return process.poll()

I’ve tried every hot solution in the post: read subprocess stdout line by line

But none of them work.

like:

for line in io.TextIOWrapper(process.stdout, encoding="utf-8"):  # or another encoding
            # line = process.stdout.readline()
            if not line:
                break
            print(line, end='')
            socketio.emit('task_output', {'output': line.strip()})

And other methods also didn’t work.

It seems only when the subprocess terminates, can all the output be received at once, which is not what is expected(line by line).

I’m really confused, wondering the principle of python subprocess, and how to get the output in time line by line.