textual.log from worker thread is not working

[dhallas]

Since textual 3.2.0 calling textual.log from a worker thread not longer works. If I revert to textual 3.1.1 logging from worker threads work correctly.

Here is an example:

from datetime import datetime

from textual import log, work
from textual.app import App, ComposeResult
from textual.widgets import Digits


class ClockApp(App):
    CSS = """
    Screen { align: center middle; }
    Digits { width: auto; }
    """

    def compose(self) -> ComposeResult:
        yield Digits("")

    def on_ready(self) -> None:
        self.update_clock()
        self.set_interval(1, self.update_clock)

    def update_clock(self) -> None:
        clock = datetime.now().time()
        self.query_one(Digits).update(f"{clock:%T}")
        self.worker()

    @work(thread=True)
    async def worker(self) -> None:
        log("Log message")


if __name__ == "__main__":
    app = ClockApp()
    app.run()

The Log message is correctly logged in textual 3.1.1 but is not logged in textual 3.2.0

[github-actions]

We found the following entries in the FAQ which you may find helpful:

• Why do some key combinations never make it to my app?
• Why doesn't Textual support ANSI themes?
• How do I fix WorkerDeclarationError?
• How can I select and copy text in a Textual app?
• How can I set a translucent app background?

Feel free to close this issue if you found an answer in the FAQ. Otherwise, please give us a little time to review.

This is an automated reply, generated by FAQtory

[TomJGooding]

You'll need to run with TEXTUAL_DEBUG=1. From the release notes for Textual v3.2.0:

Log messages could be written to stdout when there was no app, which could happen when using run_async or threads. Now they will be suppressed, unless the env var TEXTUAL_DEBUG is set

[dhallas]

Thanks for the clarification. I read the release notes, but did not think that this would be affected.

When thinking about it, we could make the developer user experience slightly better. What I am doing (and have been doing since starting using textual) is to run my application like this:

textual run --dev ./my_app.py

Why doesn't this automatically enable the TEXTUAL_DEBUG variable? If you think it would be a good idea, I can take a look at doing a PR.

[willmcgugan]

The change @TomJGooding highlighted was fixing an issue where log messages were written to stdout. The change fixed that, but breaking logging from threads was unintentional.

Fix is incoming, but note that you will need to use app.log rather than the global log.

[github-actions]

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