Table Widget doesn't render in Google Colab

[anastasia-si]

Description

Deephaven’s Table Widget isn’t rendering in Google Colab.

Steps to reproduce

Use test Google Colab notebook:
https://colab.research.google.com/drive/1Nz-ahfZQW7Hi3f7_X1LI12RTr50130Qv#scrollTo=Kz79bURo18N

Details
Browser: Chrome

Slack thread: https://illumon.slack.com/archives/C03F03BFMAB/p1659710939673389

From Colin Alworth:

it appears that the serve_kernel_port_as_iframe(dh_port) or serve_kernel_port_as_window(dh_port) call is not forwarding correctly - we either see 500s or 403s, while loading the same content locally seems to work (and it ought to be http/1.1 for at least loading the index.html, or the redirect anyway). my hunch is that someone is going to need to start with a very simple http server in python and make sure that loads, and progressively make it more and more interesting to see at what point the google collab proxy craps out.

notes that the dh_port value is embedded in the domain name - it is https://${some junk}-${more junk}-${port}-colab.googleusercontent.com , such as https://01a0wpl5ww4-496ff2e9c6d22116-17237-colab.googleusercontent.com/. Also tried appending /ide/ and /ide/index.html, but to no avail

[mofojed]

A different Google Collab notebook opening a simple web server: https://colab.research.google.com/notebooks/snippets/advanced_outputs.ipynb#scrollTo=_7dYIo63EdgL

As Colin pointed out, running something like:

from google.colab import output
output.serve_kernel_port_as_iframe(port)

... which should show the web UI, instead results in many errors. The API for server_kernel_port_as_iframe is defined here in GitHub: https://github.com/googlecolab/colabtools/blob/master/google/colab/output/_util.py#L49

I also tried adding the path to '/ide/index.html', e.g.:

from google.colab import output
output.serve_kernel_port_as_iframe(port, '/ide/index.html')

And that results in a 404:

The resulting iframe HTML was:

<iframe src="https://5bkdheicoqk-496ff2e9c6d22116-8899-colab.googleusercontent.com/ide/index.html" style="border: 0px none;" width="100%" height="400"></iframe>

[mofojed]

Actually, getting a bit further when using Chrome instead of Firefox. Still complaining about not using http2, so something in the proxy is screwing things up.

[mofojed]

Looks similar to googlecolab/colabtools#3079

[mofojed]

There are two issues at play here:

1. Instead of using localhost, need to generate the URL correctly using google.colab.kernel.proxyPort, but I don't really understand how to use that. It's only used in iframe generation here (and executed from a JS context??): https://github.com/googlecolab/colabtools/blob/master/google/colab/output/_util.py#L71. I can't really find any documentation on it. We pass the server URL to the frontend though, and it's using localhost which is a problem: https://github.com/deephaven/deephaven-ipywidgets/blob/main/deephaven_ipywidgets/deephaven.py#L63
2. We need to configure to not require/use http2: https://github.com/deephaven/deephaven-core/blob/main/server/jetty/src/main/java/io/deephaven/server/jetty/GrpcFilter.java#L28
   It looks like the Google Colab proxy only supports http1.1, possibly because it's using a service worker

There's a brief mention in the FAQ of using service workers: https://research.google.com/colaboratory/faq.html#third-party-cookies

[mofojed]

Added a ticket for being unable to set config values when using Deephaven as a library: deephaven/deephaven-core#2964
This affects item 2 above

[mofojed]

Can use JVM args to get around dh_args doing nothing:

s = Server(port=dh_port, jvm_args=["-Dhttp.requireHttp2=false"])

However, it looks like the proxy shuts down after a couple connections, so I'm not sure how to address this issue. Seems like the proxyPort is not expecting the connection to stay open? Not sure yet.

[mofojed]

We may have to do some environment inspection to figure out how to display ourselves, which is kind of gross. Take a look at plotly: https://github.com/plotly/plotly.py/blob/49dfcb1868e87627f032731ef2ac48e37891baf4/packages/python/plotly/plotly/io/_renderers.py#L472

[jnumainville]

Created colab ticket: googlecolab/colabtools#3308

[mofojed]

@jnumainville the GitHub issue created in colabtools hasn't seen any action yet (may just be because of the holidays). Could try making a Stack Overflow question for this as well: https://stackoverflow.com/questions/tagged/google-colaboratory

They don't seem to have a community channel or anything to ask questions that I can find :(

[jnumainville]

https://stackoverflow.com/questions/74998386/connection-to-localhost-proxy-breaking