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m-lab / ndt-server

docker native ndt5 and ndt7 server with prometheus integration
https://www.measurementlab.net/
Apache License 2.0
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ndt-server: disable http2 for ndt7 and ndt5 #270

Open bassosimone opened 4 years ago

bassosimone commented 4 years ago

By default Go enables http2, however gorilla/websocket does not support http2. So, we need to disable http2 otherwise a client may attempt to perform WebSocket using http2, as instructed by ALPN, but that process fails. This Stack Overflow thread may be useful to show us how to disable http2.

stephen-soltesz commented 4 years ago

Does the current code impact browser clients?

bassosimone commented 4 years ago

When I fetch https://ndt-iupui-mlab2-mil03.measurement-lab.org/ with chrome, it's using h2. Same when I navigate to https://ndt-iupui-mlab2-mil03.measurement-lab.org/static/ndt7.html. Yet Chrome performs the test using secure WebSocket. I believe the browser does not use h2 for WebSocket for now and I have seen there is an experimental flag for enabling it. Then, I found an authoritative source:

WebSockets over HTTP/2 [...] would only be used for secure WebSockets requests, and only if there is already an HTTP/2 connection where the server has already advertised support for WebSockets over HTTP/2 via the HTTP/2 SETTINGS parameter defined in the specification.

So, the answer to your question, @stephen-soltesz is "no".

stephen-soltesz commented 4 years ago

I believe this issue is obsolete. Please reopen if you disagree.

bassosimone commented 4 years ago

@stephen-soltesz has it been fixed by disabling h2? While it's not breaking clients now, it may break clients in the future when h2 increasingly becomes the norm, for this reason I think it is better to keep it open. The quote above, pulled from a discussion of a Chrome feature, explains the policy that Chrome is currently using vis a vis h2. Yet, our server is still replying with h2 http/1.1 in the ALPN. Also, while that is Chrome's policy, and while Firefox appears to be using a Chrome-like policy, it may be that in the future Firefox or other browsers may change policy. So, I'd keep this issue open.

(But I don't have the power to re-open the issue, so I think I cannot do myself the "reopen if you disagree" part.)

bassosimone commented 4 years ago

Thanks!