Uploading a 10MB file fails -> `http: superfluous response.WriteHeader call from main.whoamiHandler (app.go:234)`

[spatterIight]

When uploading medium to large sized files the following errors occurs:

In the Modsecurity docker container:

[Thu Jan 30 18:49:11.149140 2025] [proxy_http:error] [pid 29:tid 135571558902584] [client 172.18.0.8:40496] AH01097: pass request body failed to 172.18.0.5:80 (dummy) from 172.18.0.8 (), referer: https://domain.localhost/index.html

In the Traefik whoami container:

2025/01/30 18:46:57 Starting up on port 80
2025/01/30 18:49:11 http: superfluous response.WriteHeader call from main.whoamiHandler (app.go:234)

This occurs when uploading files larger than around 10MB. This test file is enough to replicate it for me. The two errors consistently occur in each container with the failed upload.

Thanks, this plugin is awesome

---

P.S. to encounter this error I first had to increase the Modsecurity max file upload limit and Traefik plugin timeouts as follows:

 MODSEC_REQ_BODY_LIMIT=262144000 # 250 MiB
 and
 timeoutMillis: 100000

Otherwise I get a timeout error w/ Traefik -> 2025/01/30 18:55:19 fail to send HTTP request to modsec: Post "http://modsecurity:8080/api/sharedfile/": context deadline exceeded (Client.Timeout exceeded while awaiting headers)

[spatterIight]

We were able to solve this by replacing Traefik/whoami with a simple NodeJS HTTP web server that always returns 200.

[troyxmccall]

Thank you for these details, @spatterIight; I'll play around with this a bit and see what our options are