Troubleshooting "Connecting..." hang on macOS (Apple Silicon) - VNC Timeout?

[Dev-sh21]

Hi @jmplaza @javizqh ,

I'm setting up Robotics Academy locally on my Mac (M1/M2) using Docker, and I've been running into an issue where the application verifies application_running but the frontend stays stuck on the "Connecting..." dialog indefinitely.

Symptoms:

The container starts and is healthy (docker ps shows it up).
The web interface loads (localhost:7164).
WebSockets connect initially but then seem to drop or fail to establish the VNC stream.
Findings: After digging into the logs and the container, I suspect this might be a timeout issue specific to emulated environments (Rosetta/QEMU on ARM64).

The vnc_server.py script has a hardcoded timeout of 20 seconds for the VNC port to become available: def wait_for_port(self, host, port, timeout=20):

On my machine, due to emulation overhead, the Xorg/TurboVNC server takes about 30-40 seconds to initialize. This causes the Manager to raise a TimeoutError and exit silently before the frontend can fully connect.

Has anyone else on Apple Silicon experienced this? Should we consider increasing this default timeout to accommodate non-native Docker setups? I'd be happy to open a PR if this is a valid improvement.

Thanks!

[Sarvesh-Mishra1981]

Hello @Dev-sh21
Yes the problem persist with Macos, It will be better if something is figured out.

[javizqh]

Have you followed the developer guide or the user guide?

[Dev-sh21]

Hi @javizqh, thanks for the reply!

Yes, I followed the standard User Guide for Docker installation (docker pull & docker run). The installation itself works perfectly, and the containers start healthy.

However, the issue is a specific race condition on macOS (ARM64) due to emulation overhead. The guides assume the VNC server starts within 20 seconds, but on Apple Silicon (Rosetta), it takes ~35 seconds.

The vnc_server.py script has a hardcoded limit:

def wait_for_port(self, host, port, timeout=20):

[javizqh]

Can you try checking this from our developer guide?

[Dev-sh21]

Hi @javizqh,

yes, i have verified my Docker settings (see attached screenshot)
"Use Rosetta for x86_64/amd64 emulation on Apple Silicon" is definitely enabled
i am also using the Apple Virtualization framework and VirtioFS, so my docker setup is as optimized as possible

despite these settings, the amd64 VNC server consistently takes around 35-40 seconds to initialize on my m1/m2 chip. since the hardcoded timeout in vnc_server.py is 20 seconds, it crashes every single time

the issue was only resolved when I manually patched the file inside the container to increase the timeout
def wait_for_port(self, host, port, timeout=120)

once I applied this patch, the connection succeeded immediately

i believe increasing this default timeout would be a great quality-of-life improvement for all macOS users, as even with rosetta, the 20s limit is too tight.

[Dev-sh21]

hi @jmplaza @javizqh
following up on this,
since the vnc timeout is blocking issue for macos (arm 64) users due due to lower start up time, around 35 sec, i have prepared a fix-

1. increase the default timeout to 60s as the safe value,
2. what we can do is, we can make the timeout configurable, via environment variable, so we dont need to change the code for differenet machines in future

I will submit the pr shortly for your review

[jmplaza]

Is this Discussion closable @Dev-sh21 as #3484 PR has been merged?

[Dev-sh21]

hi @jmplaza sir, yes the PR is meged and i am closing the issue