No Image when using interface.py on Google Colab about 3d-ken-burns

[edenraf]

For anyone else looking into this, I have found a fix. The error message comes from a websocket that is already open. I assume google colabs is using the 8080 port for something else.
So, I went into interface.py to line 212 and changed the port to 1234.
Then change the port call print(eval_js("google.colab.kernel.proxyPort(1234)"))
Done

[sniklaus]

Thank you for the detailed documentation! I was able to replicate your findings and my best guess is that Colab's proxy is unable to handle the /get_live request since this request is actually a stream and does not terminate. Since I am not super familiar with Colab, I am afraid that I do not know how to persuade Colab's proxy to forward such request. If anyone has any suggestions then Doug and I would be grateful for any hints.

[Roemer]

It actually seems to work you just have to wait quite long. One issue there is, is that the requests to update_from/to are unthrottled.
I added a jquery throttler (https://github.com/cowboy/jquery-throttle-debounce) and that makes it more responsive.
I also adjusted the interface to take a port as a parameter. If wanted, I can create a PR with those changes.

[sniklaus]

Thank you for looking into this and sharing your findings! It would be great if you could fork this project and commit your changes there. I would be happy to point the readme to your fork such that people interested in this setup can make use of your modifications.

[Roemer]

So I did some more research. The live stream that should be there does not work. I think this is some kind of colab limitation. What I tried now is to add a toggle button to switch between the stream preview and a still image which is refreshed on every update call. It works actually fairly well and allows the use of colab to view a preview. Surely not as smooth as with the stream but definitely better than nothing. I will open a PR for it, you can close it if you don't want to merge any changes.

[edenraf]

@Roemer would you be able to post a little more code so I could replicate the interface on my colab? I tried using the code you posted at the top but get the following error. Perhaps I need to modify the interface.py to expect the google colabs link instead of localhost? Any help greatly appreciated!

Traceback (most recent call last): File "interface.py", line 213, in <module> gevent.pywsgi.WSGIServer(listener=('0.0.0.0', 8080), application=objFlask).serve_forever() File "/usr/local/lib/python3.7/dist-packages/gevent/baseserver.py", line 398, in serve_forever self.start() File "/usr/local/lib/python3.7/dist-packages/gevent/baseserver.py", line 336, in start self.init_socket() File "/usr/local/lib/python3.7/dist-packages/gevent/pywsgi.py", line 1545, in init_socket StreamServer.init_socket(self) File "/usr/local/lib/python3.7/dist-packages/gevent/server.py", line 180, in init_socket self.socket = self.get_listener(self.address, self.backlog, self.family) File "/usr/local/lib/python3.7/dist-packages/gevent/server.py", line 192, in get_listener return _tcp_listener(address, backlog=backlog, reuse_addr=cls.reuse_addr, family=family) File "/usr/local/lib/python3.7/dist-packages/gevent/server.py", line 288, in _tcp_listener sock.bind(address) File "/usr/local/lib/python3.7/dist-packages/gevent/_socketcommon.py", line 563, in bind return self._sock.bind(address) OSError: [Errno 98] Address already in use: ('0.0.0.0', 8080)

[sniklaus]

Huge thanks for sharing this information! I am hence closing this issue for now. 👍