"Could not connect to the Swift simulator" in Colab/Remote Notebook

[YuhengZhi]

Even though it looks like the implementation of SwiftRoute is attempting to support Colab, my recent tries to run the example code (the piece for running in jupyter notebook) in a Colab notebook has failed with the error message "Could not connect to the Swift simulator ". The same error is given when run in a remote non-colab notebook served on a personal server (but opened via the remote-ssh plugin of vs code).

The same code runs fine on a local jupyter notebook though. Both RTB and Swift are the latest versions via PIP.

I am sorry that web programming is not my most vital skill, so some initial digging & print statements on my side were not very fruitful. All I was able to identify was that this line timed out in the remote notebook, but returned "Connected" in a local notebook.

[martinezpenya]

I'm facing the same issue... I have a local notebook on docker container with python robotics, swift, etc... and I'm getting same error when trying to connect to Swift. Any update?

[Davian1704]

I faced similar issues while trying to use the swift simulator on a jupyterhub running on a docker on the host machine. I've managed to fix it by changing the following:

In swift/SwiftRoute.py

I changed the websocket creation to be:

    start_server = websockets.serve(self.serve, "0.0.0.0", port)

I changed the url of the Swift Simulator to match the domain assigned to the server we are using, but if ran locally, localhost should be fine:

    url = f"http://domain:{server_port}/?{socket_port}"

Additionally, in the do_GET method I changed the address to match that of the url of the Swift Simulator:

    self.send_header(
        "Location",
        "http://domain:"
        + str(server_port)
        + "/?"
        + str(socket_port),
    )

In swift/out/_next/static/chunks/pages/index-0723cc3b940b78c7.js

The only change needed here was regarding to connecting to it through a domain, if not using a domain, localhost should work:

    var o="ws://domain:"+i+"/";

Additional Considerations

In the dockerfile, make sure that all the ports used by both the simulator and websocket are exposed and correctly mapped.

Here is the branched repository of swift-sim we use on our server: Repository

[romance-2022]

I'm facing the same issue @YuhengZhi , it's really the remoteness that causes the problem