iframe CORS error

[laszlokorte]

Environment

• Elixir & Erlang/OTP versions (elixir --version): Elixir 1.13.3, Erlang/OTP 24 [erts-12.0]
• Operating system: Windows 10
• How have you started Livebook (mix phx.server, livebook CLI, Docker, etc): livebook server
• Livebook version (use git rev-parse HEAD if running with mix): 0.6.0
• Browsers that reproduce this bug (the more the merrier): Firefox, Edge, Chrome
• Include what is logged in the browser console: TypeError: NetworkError when attempting to fetch resource.
• Include what is logged to the server console: Nothing

Current behavior

VegaLite do not render.

Chromes displays the most detailed error in the browser console:

Access to fetch at 'http://localhost:8081/iframe/v3.html' from origin 'http://localhost:8080' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

Fetching http://localhost:8081/iframe/v3.html manually via curl or Browser results in a HTTP 404 "Not Found".

I noticed that there are existing issues #1014 and #971 describing a similar error but it looks like the issue was to be fixed in version 0.6.0. For me the issue persists. Deleting Path.join(System.tmp_dir!(), "livebook") did not work for me.

Expected behavior

I expect the plots render and no CORS error to occur.

[josevalim]

Is there something else running on port 8081? What happens if you curl the root?

[laszlokorte]

Nothing else listens on 8081. While livebook is running GET http://localhost:8081 gives me a 404 as well. If livebook is not running GET http://localhost:8081 times out.

[laszlokorte]

Running via dockers works as expected. Via docker GET http://localhost:8081 still gives a 404 not found but http://localhost:8081/iframe/v3.html gives an html file with some javascript.

[josevalim]

Does http://localhost:8081/iframe/v2.html work for you locally?

[laszlokorte]

Maybe I am doing something wrong but:

When running livebook via docker (Docker Desktop on Windows) both http://localhost:8081/iframe/v2.html and http://localhost:8081/iframe/v3.html work from inside the Browser on the Windows machine.

When running livebook on Windows itself via $ livebook server none of the v2/v3 iframes work but http://localhost:8080 does.

Now if I attach to the docker container itself wget -O - http://localhost:8081/iframe/v2.html (and v3) does give a 404 as well, but wget -O - http://localhost:8080/ does work.

[jonatanklosko]

Oh, the hex package doesn't include the iframes :( I didn't notice it when testing livebook from hex, because the iframes got cached. Fixed in #1174, though we need a new version.

[laszlokorte]

Thank you both for your quick replies! #1174 fixed it for me 😊

[jonatanklosko]

I've just released 0.6.1, should work as expected from Hex :)