Is is possible to continuously update TextLog from a running process?

[ghost]

I'm trying to continuously write to a TextLog widget from a subprocess call, but it seems output is blocked until the call finishes. I have a minimal (non-)working example below (without Textual it works and updates line by line, but not with Textual TextLog). Any ideas would be appreciated?

from subprocess import PIPE, STDOUT, Popen
from textual.app import App
from textual.widgets import Footer, TextLog

class UI(App):

    BINDINGS = [("1", "run", "run"),]

    def compose(self):
        yield TextLog()
        yield Footer()

    def action_run(self):
        log = self.query_one(TextLog)
        log.write("start")

        args = ["bash", "-c", "echo foo;sleep 3;echo bar"]

        proc = Popen(args, stdout=PIPE, stderr=STDOUT, text=True)
        while proc.poll() is None:
            line = proc.stdout.readline()
            if line:
                log.write(line)

if __name__ == "__main__":
    UI().run()

[willmcgugan]

You will need to make your action concurrent. The Textual way to do this is with the worker API.

Note the addition of the decorator, and call_from_thread.

from subprocess import PIPE, STDOUT, Popen
from textual.app import App
from textual.widgets import Footer, TextLog
from textual import work


class UI(App):
    BINDINGS = [
        ("1", "run", "run"),
    ]

    def compose(self):
        yield TextLog()
        yield Footer()

    @work
    def action_run(self):
        log = self.query_one(TextLog)
        log.write("start")

        args = ["bash", "-c", "echo foo;sleep 3;echo bar"]

        proc = Popen(args, stdout=PIPE, stderr=STDOUT, text=True)
        while proc.poll() is None:
            line = proc.stdout.readline()
            if line:
                self.call_from_thread(log.write, line)


if __name__ == "__main__":
    UI().run()

[ghost]

Thank you! That was it.