Live Reload not working on Windows

[MisterArbazzz]

Why does live reloading not work in my H2O Wave app?

I am unable to see the changes in the Wave app as I am coding, and I have to restart the app to see the effect.

I trying to run this demo app and making some changes in it but whenever i make change to the code.

I get this error

WARNING:  StatReload detected changes in 'app.py'. Reloading...
INFO:     Started server process [8720]
INFO:     Waiting for application startup.
ERROR:    Traceback (most recent call last):
  File "c:\python37\lib\site-packages\anyio\_core\_sockets.py", line 167, in try_connect
    stream = await asynclib.connect_tcp(remote_host, remote_port, local_address)
  File "c:\python37\lib\site-packages\anyio\_backends\_asyncio.py", line 1628, in connect_tcp
    StreamProtocol, host, port, local_addr=local_addr
  File "c:\python37\lib\asyncio\base_events.py", line 962, in create_connection
    raise exceptions[0]
  File "c:\python37\lib\asyncio\base_events.py", line 949, in create_connection
    await self.sock_connect(sock, address)
  File "c:\python37\lib\asyncio\selector_events.py", line 473, in sock_connect
    return await fut
  File "c:\python37\lib\asyncio\selector_events.py", line 503, in _sock_connect_cb
    raise OSError(err, f'Connect call failed {address}')
ConnectionRefusedError: [Errno 10061] Connect call failed ('127.0.0.1', 10101)

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "c:\python37\lib\site-packages\httpcore\_exceptions.py", line 10, in map_exceptions
    yield
  File "c:\python37\lib\site-packages\httpcore\_backends\anyio.py", line 117, in connect_tcp
    local_host=local_address,
  File "c:\python37\lib\site-packages\anyio\_core\_sockets.py", line 225, in connect_tcp
    raise OSError("All connection attempts failed") from cause
OSError: All connection attempts failed

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "c:\python37\lib\site-packages\httpx\_transports\default.py", line 60, in map_httpcore_exceptions
    yield
  File "c:\python37\lib\site-packages\httpx\_transports\default.py", line 353, in handle_async_request
    resp = await self._pool.handle_async_request(req)
  File "c:\python37\lib\site-packages\httpcore\_async\connection_pool.py", line 262, in handle_async_request
    raise exc
  File "c:\python37\lib\site-packages\httpcore\_async\connection_pool.py", line 245, in handle_async_request
    response = await connection.handle_async_request(request)
  File "c:\python37\lib\site-packages\httpcore\_async\connection.py", line 92, in handle_async_request
    raise exc
  File "c:\python37\lib\site-packages\httpcore\_async\connection.py", line 69, in handle_async_request
    stream = await self._connect(request)
  File "c:\python37\lib\site-packages\httpcore\_async\connection.py", line 117, in _connect
    stream = await self._network_backend.connect_tcp(**kwargs)
  File "c:\python37\lib\site-packages\httpcore\_backends\auto.py", line 36, in connect_tcp
    socket_options=socket_options,
  File "c:\python37\lib\site-packages\httpcore\_backends\anyio.py", line 121, in connect_tcp
    stream._raw_socket.setsockopt(*option)  # type: ignore[attr-defined] # pragma: no cover
  File "c:\python37\lib\contextlib.py", line 130, in __exit__
    self.gen.throw(type, value, traceback)
  File "c:\python37\lib\site-packages\httpcore\_exceptions.py", line 14, in map_exceptions
    raise to_exc(exc) from exc
httpcore.ConnectError: All connection attempts failed

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "c:\python37\lib\site-packages\starlette\routing.py", line 686, in lifespan
    async with self.lifespan_context(app) as maybe_state:
  File "c:\python37\lib\site-packages\starlette\routing.py", line 575, in __aenter__
    await self._router.startup()
  File "c:\python37\lib\site-packages\starlette\routing.py", line 663, in startup
    await handler()
  File "c:\python37\lib\site-packages\h2o_wave\server.py", line 303, in _register
    raise exception
  File "c:\python37\lib\site-packages\h2o_wave\server.py", line 293, in _register
    key_secret=_config.app_access_key_secret,
  File "c:\python37\lib\site-packages\h2o_wave\server.py", line 241, in call
    content=marshal({method: kwargs}),
  File "c:\python37\lib\site-packages\httpx\_client.py", line 1861, in post
    extensions=extensions,
  File "c:\python37\lib\site-packages\httpx\_client.py", line 1530, in request
    return await self.send(request, auth=auth, follow_redirects=follow_redirects)
  File "c:\python37\lib\site-packages\httpx\_client.py", line 1621, in send
    history=[],
  File "c:\python37\lib\site-packages\httpx\_client.py", line 1648, in _send_handling_auth
    history=history,
  File "c:\python37\lib\site-packages\httpx\_client.py", line 1682, in _send_handling_redirects
    response = await self._send_single_request(request)
  File "c:\python37\lib\site-packages\httpx\_client.py", line 1719, in _send_single_request
    response = await transport.handle_async_request(request)
  File "c:\python37\lib\site-packages\httpx\_transports\default.py", line 353, in handle_async_request
    resp = await self._pool.handle_async_request(req)
  File "c:\python37\lib\contextlib.py", line 130, in __exit__
    self.gen.throw(type, value, traceback)
  File "c:\python37\lib\site-packages\httpx\_transports\default.py", line 77, in map_httpcore_exceptions
    raise mapped_exc(message) from exc
httpx.ConnectError: All connection attempts failed

ERROR:    Application startup failed. Exiting.

and app shuts down

i am using the latest h2o-wave Version: 0.26.1
with python 3.7.9
on windows 11

I need to see the changes in the wave ui as i am coding (also i tried it using both vscode and pycharm)
Can someone please assist me. @mturoci

[mturoci]

Hi @MisterArbazzz!

Based on the logs you attached, the reloading works fine. The problem is that the app is not able to connect to wave server, which should be running on port 10101. Can you verify if the there is a process running on port 10101? If it is, you need to figure out why it cannot be reached. If it's not running, you need to figure out why it was shut down.

[MisterArbazzz]

Hi! @mturoci, thanks a lot for your reply

Yes, a process is running on 10101 after i run the app with wave run app

But after i make changes to the app.py (for eg. changing the heading)
The app shuts down

The details of port 10101 can be seen after the apps shut down

I can not figure out why it shuts down.

[mturoci]

Managed to repro on Windows machine. Will need to fix on our side. Thanks for reporting!

[MisterArbazzz]

Oh okay :)
Although i found a work around. If you start an app on port 10101 (which you don't wish to work on) and then start another app on the same port (which you wish to work on), then reloading works fine!

[mturoci]

Cool. I just found the cause - the newest version of uvicorn (0.22.0). So a tmp workaround would be downgrading it (e.g. pip install uvicorn==0.21.1). Let me know if this works for you as well.

In the meantime, I will dig into what's the exact cause and release a new Wave version without necessary workarounds.

[MisterArbazzz]

Yes!!! It works for me as well.
Thank you so much! You just saved me a whole lot of time.

[mturoci]

Glad it worked, please mark it as selected answer so that anyone else stumbling upon this can get the solution rightaway :)

[MisterArbazzz]

Yep, done. Btw i see all your tech talks, you are an inspiration to the young generation in the tech world :)