[REF-3184] All my rx.background don't work on 0.5.5

[fungalspores]

Hello everyone

All my rx.background don't work on 0.5.5

You can try make any foreach with rx.background and yield Anystate.do_this and it won't work

I can show my code to DM any contributors

_REF-3184

[masenf]

@fungalspores can you share your code with me, [email protected]. Or share a minimal reproducer here in this issue.

I'm not able to reproduce the issue with the following code

import asyncio
import reflex as rx


class MyTaskState(rx.State):
    counter: int = 0
    max_counter: int = 10
    running: bool = False
    _n_tasks: int = 0

    def foo(self):
        print("foo")

    @rx.background
    async def my_task(self):
        async with self:
            # The latest state values are always available inside the context
            if self._n_tasks > 0:
                # only allow 1 concurrent task
                return

            # State mutation is only allowed inside context block
            self._n_tasks += 1

        while True:
            async with self:
                # Check for stopping conditions inside context
                if self.counter >= self.max_counter:
                    self.running = False
                if not self.running:
                    self._n_tasks -= 1
                    return

                self.counter += 1
                yield MyTaskState.foo

            # Await long operations outside the context to avoid blocking UI
            await asyncio.sleep(0.5)

    def toggle_running(self):
        self.running = not self.running
        if self.running:
            return MyTaskState.my_task

    def clear_counter(self):
        self.counter = 0


def background_task_example():
    return rx.hstack(
        rx.heading(MyTaskState.counter, " /"),
        rx.chakra.number_input(
            value=MyTaskState.max_counter,
            on_change=MyTaskState.set_max_counter,
            width="8em",
        ),
        rx.button(
            rx.cond(~MyTaskState.running, "Start", "Stop"),
            on_click=MyTaskState.toggle_running,
        ),
        rx.button(
            "Reset",
            on_click=MyTaskState.clear_counter,
        ),
    )

I think I'm missing the part about the foreach, not sure how that looks for the issue you are hitting.

[seewindcn]

about return MyTaskState.my_task code, I have another question:
In my memory, function toggle_running return MyTaskState.my_task, will send a message to web page, and then web page's applyEvent send back to server, and server run my_task in _process_background.
my question: can it be more direct no through the web? or is there a function maybe name run_tasks can use to direct run a backgroup task? @masenf

[fungalspores]

@fungalspores can you share your code with me, [email protected]. Or share a minimal reproducer here in this issue.

I'm not able to reproduce the issue with the following code

import asyncio
import reflex as rx


class MyTaskState(rx.State):
    counter: int = 0
    max_counter: int = 10
    running: bool = False
    _n_tasks: int = 0

    def foo(self):
        print("foo")

    @rx.background
    async def my_task(self):
        async with self:
            # The latest state values are always available inside the context
            if self._n_tasks > 0:
                # only allow 1 concurrent task
                return

            # State mutation is only allowed inside context block
            self._n_tasks += 1

        while True:
            async with self:
                # Check for stopping conditions inside context
                if self.counter >= self.max_counter:
                    self.running = False
                if not self.running:
                    self._n_tasks -= 1
                    return

                self.counter += 1
                yield MyTaskState.foo

            # Await long operations outside the context to avoid blocking UI
            await asyncio.sleep(0.5)

    def toggle_running(self):
        self.running = not self.running
        if self.running:
            return MyTaskState.my_task

    def clear_counter(self):
        self.counter = 0


def background_task_example():
    return rx.hstack(
        rx.heading(MyTaskState.counter, " /"),
        rx.chakra.number_input(
            value=MyTaskState.max_counter,
            on_change=MyTaskState.set_max_counter,
            width="8em",
        ),
        rx.button(
            rx.cond(~MyTaskState.running, "Start", "Stop"),
            on_click=MyTaskState.toggle_running,
        ),
        rx.button(
            "Reset",
            on_click=MyTaskState.clear_counter,
        ),
    )

I think I'm missing the part about the foreach, not sure how that looks for the issue you are hitting.

I wrote to your mail and try added to discord friend for faster communication

[Ernelene]

I had a similar issue: I was able to resolve it by removing the nested async with self:

 @rx.background
 async def fetch_data(self):
        async with self:
            p = await self.get_state(PState)
            self.p_id = p.get_current_p_id 
            if self.p_id == "":
                return rx.redirect("/ws")
            wf = await self.fetch_flow()
            self.wf_id = wf
            while self.wf_status != "Completed":
                wf_status = await self.fetch_flow_run_id()
                async with self:
                    self.wf_status = wf_status["state"]
....

Previously I had an issue if the state not updating in my while -> so I added the extra async with self: in the while loop. Now with the new update the state did not want to update because of the extra async with self: so I removed it.
In my case if you add print statements you will see everything updating up to the second async with self and then not updating after it.

[masenf]

@Ernelene thank you for the insight!

It appears this issue was introduced by #3508 where i added locking around the async with self to avoid concurrent access