Language servers fail to start in WSL under proxy

[kv9898]

I had been using my custom WSL extension fine until recently. It turned out that neither R nor Python language servers now work under a proxy, and when I turn the proxy off they work as expected. I wonder if there have been any recent changes to Positron that have brought this change?

[kv9898]

If the output from the Kernel Supervisor is helpful:

ix/run/user/1000/kc-9567.sock:/status","isUnix":true},"method":"GET","headers":{"Accept":"application/json","Authorization":"Bearer 49fec745e5670463"}}},"statusCode":400,"name":"HttpError"}
06:15:45 [Positron] Failed to start Kallichore server: HttpError: HTTP request failed
06:15:57 [Positron] Using connection file from POSITRON_SUPERVISOR_CONNECTION_FILE: /home/dianyi/.config/Positron/positron-supervisor-8778.json
06:15:57 [Positron] Reconnecting to Kallichore server at socket:/run/user/1000/kc-9567.sock (PID 9567)
06:15:57 [Positron] Reconnecting to socket: /run/user/1000/kc-9567.sock
06:15:57 [Positron] Streaming Kallichore server logs at /tmp/kallichore-e0fbe6c4-9498.log
06:15:44 [INFO] Using Unix domain socket: /run/user/1000/kc-9567.sock
06:15:44 [INFO] Generated random auth token: 49fec745e5670463
06:15:44 [INFO] Wrote connection details to /home/dianyi/.config/Positron/positron-supervisor-8778.json
06:15:44 [DEBUG] (1) kcserver: Starting Kallichore
06:15:44 [INFO] Server set to shut down after 1 hours of inactivity
06:15:57 [Positron] Error connecting to Kallichore (/home/dianyi/.config/Positron/positron-supervisor-8778.json): HTTP 400. 
06:15:57 [Positron] Using native IPC transport: unix sockets
06:15:57 [Positron] Starting Kallichore server /home/dianyi/.positron-server/bin/fd2186c301ecb6913b9614e22fe22c5423c6acdc/extensions/positron-supervisor/resources/kallichore/kcserver with connection file /home/dianyi/.config/Positron/positron-supervisor-8778.json
06:15:57 [Positron] Read domain socket connection information from /home/dianyi/.config/Positron/positron-supervisor-8778.json: /run/user/1000/kc-9834.sock, constructed base path: http://unix:/run/user/1000/kc-9834.sock:
06:15:57 [Positron] Failed to get initial server status from Kallichore; server may not be running or may not be ready. Check the terminal for errors. Error: {"response":{"statusCode":400,"headers":{"content-length":"0","date":"Wed, 13 Aug 2025 06:15:57 GMT"},"request":{"uri":{"protocol":"http:","slashes":true,"auth":null,"host":"/run/user/1000/kc-9834.sock","port":80,"hostname":"/run/user/1000/kc-9834.sock","hash":null,"search":null,"query":null,"pathname":"/status","path":"/status","href":"http://unix/run/user/1000/kc-9834.sock:/status","isUnix":true},"method":"GET","headers":{"Accept":"application/json","Authorization":"Bearer 97c0b6d0039ad135"}}},"statusCode":400,"name":"HttpError"}

[lionel-]

By WSL extension do you mean https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-wsl?

I'm confused as to what it means for the R and Python LSP to run under a proxy, how that happens exactly, and how is that related to the WSL extension.

cc @jmcphers

[kv9898]

it's this one: https://open-vsx.org/extension/kv9898/open-remote-wsl/

Since I'm in China, I have to use a proxy/VPN to access Western sites (even github). FYI, I'm using geph as my proxy.

[lionel-]

Thanks for the context!

Would you be able to disable the vpn for local traffic?

Also from your logs I see that Positron tries to connect to the Kallichore server via an http over Unix socket scheme:

constructed base path: http://unix:/run/user/1000/kc-9834.sock:

Could you disable the vpn for URLs starting with http://unix:?

[kv9898]

I have added unix: and unix to NO_PROXY env variable but it doesn't seem to make much of a difference. I also tried another proxy (tuxing) and that also blocks Positron in WSL. The weird thing is that they work alright for native Windows and they used to work in WSL in earlier versions of Positron.

[jmcphers]

Do you still see this problem if you revert to the TCP transport? You can set this here (requires full restart):

[kv9898]

This worked! Thanks for the suggestion!

[jmcphers]

OK, glad that's all it was! I'm not sure why the domain socket isn't working in WSL (it's supposed to be supported...) but we'll investigate. I've filed this with some of your logs in #9047.