Reverse proxy with Traefik on sub-path leads to a HTTP 302 redirection loop

[gelven4sec]

Description

The title of the issue should be clear, I uploaded a screenshot below.

Here's my Gitea compose :

version: "3"

networks:
  proxy:
    external: true

services:
  gitea:
    image: gitea/gitea:1.18
    container_name: gitea
    environment:
      - USER_UID=1000
      - USER_GID=1000
      - ROOT_URL=https://<MY DOMAIN>/git/
      - OFFLINE_MODE=true
      - DISABLE_SSH=true
      - RUN_MODE=dev
    restart: always
    networks:
      - proxy
    volumes:
      - ./data:/data
      - /etc/timezone:/etc/timezone:ro
      - /etc/localtime:/etc/localtime:ro
    ports:
      - 3000:3000
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.gitea.tls=true"
      - "traefik.http.routers.gitea.rule=Host(`<MY DOMAIN>`) && PathPrefix(`/git/`)"
      - "traefik.http.services.gitea.loadbalancer.server.port=3000"

I tried every combination of trailing slashes with ROOT_URL and PathPrefix, couldn't make it work.
If I remove ROOT_URL and access it from https://<MY DOMAIN>:3000 it works fine.

The logs should give you relevant informations.

If we get to find the solution, I would be happy to contribute to documentation about sub-path with traefik like other proxies.

Gitea Version

1.18.4 (Digest: fc835996f659)

Can you reproduce the bug on the Gitea demo site?

No

Log Gist

https://gist.github.com/sven-eliasen/7f9ee471b212417f82f66e9cb0527226

Screenshots

Git Version

No response

Operating System

RHEL

How are you running Gitea?

Running with docker, see description for compose.

Database

SQLite

[wxiaoguang]

You need to remove the subpath from Traefik side before passing the request to Gitea.

For example: if a user accesses https://domain/git/ to Traefik, on Gitea side Gitea must seeGET / but not GET /git/

[gelven4sec]

You need to remove the subpath from Traefik side before passing the request to Gitea.

So I should do something like a rewrite in nginx ?

[wxiaoguang]

Google: traefik remove path prefix

https://doc.traefik.io/traefik/middlewares/http/stripprefix/

https://stackoverflow.com/questions/71398933/how-to-strip-the-path-prefix-in-kubernetes-traefik-ingress

[gelven4sec]

I appended this at my labels :
- "traefik.http.middlewares.gitea.stripprefix.prefixes=/git"

But seeing my logs, Gitea still receives /git/

[gelven4sec]

Even tried this :
- "traefik.http.middlewares.gitea.stripprefixregex.regex=^\/git"

I can see the middleware in Traefik dashboard but it still doesn't seem to work.

[wxiaoguang]

Hmm ... I can only provide these hints but I am not using traefik .... so sorry I have no idea about why traefik stripprefix doesn't work.

[gelven4sec]

Hmm ... I can only provide these hints but I am not using traefik .... so sorry I have no idea about why traefik stripprefix doesn't work.

I'll try to get some help by the traefik community.

Thanks for you help ! You sure led my on the right path.

Hope you don't mind keeping this issue open for a while, in case anyone seeing this could help, I'll try to get back here as soon as I get a solution, and update Gitea doc btw.

[techknowlogick]

Hope you don't mind keeping this issue open for a while, in case anyone seeing this could help.

Of course :) It may get closed in the future, but can always be re-opened.

I'll try to get back here as soon as I get a solution, and update Gitea doc btw.

That would be very appreciated <3 traefik with sub-path is something we don't have documented yet and so any help would be lovely.

[gelven4sec]

Okay I finally got this right !

Due to my poor knowledge about Traefik, I though setting up the middleware with the same name as the service would automatically assign it.

Solution :

labels:
      - "traefik.enable=true"
      - "traefik.http.routers.gitea.tls=true"
      - "traefik.http.routers.gitea.rule=Host(`domain`) && PathPrefix(`/git`)"
      - "traefik.http.services.gitea.loadbalancer.server.port=3000"
      - "traefik.http.middlewares.gitea-stripprefix.stripprefix.prefixes=/git"
      - "traefik.http.routers.gitea.middlewares=gitea-stripprefix"

I would be happy to provide a PR to update the documentation, which would close this ticket.