feat: introduce --abs-proxy-base-path that allows app proxying while code-server is not server at the root

[rafaelnferreira]

What it is

• Allows proxy traffic to be properly routed when code-server is served under a path.

How

• Introduces a new switch abs-proxy-base-path.
• When specified, absproxy requests will be forwarded using the value as prefix

Example

• Code server is hosted at: my-codeserver.com/user/123
• React App is started at port 8080 under PUBLIC_PATH /user/123
• abs-proxy-base-path set to /user/123
• A GET request to my-codeserver.com/user/123/absproxy/8080/app will properly reach the app.

Fixes #6770

[code-asher]

This is great thank you for implementing!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Please upload report for BASE (main@39ce82a). Learn more about missing BASE report.
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6958   +/-   ##
=======================================
  Coverage        ?   72.63%           
=======================================
  Files           ?       31           
  Lines           ?     1904           
  Branches        ?      412           
=======================================
  Hits            ?     1383           
  Misses          ?      441           
  Partials        ?       80           

Files	Coverage Δ
src/node/cli.ts	90.90% <ø> (ø)
src/node/routes/index.ts	76.41% <ø> (ø)
src/node/routes/pathProxy.ts	82.14% <100.00%> (ø)

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 39ce82a...71d10b1. Read the comment docs.

[code-asher]

Looks like our formatter is being a bit weird, let me fix it real quick

Edit: actually not sure what is going on, CI seems to format a little differently compared to local...I will undo the indentation for now and figure it out later.

[yuzhuoheng]

abs-proxy-base-path It didn't work. This is my startup command:

I tried to open it with a browser, and the page prompt was as follows:

[code-asher]

This flag is just for code-server's built-in proxy (to proxy to other applications on the remote), not for code-server itself.

To serve code-server itself at a base path, you should use a reverse proxy like NGINX or Caddy.

[itay-nvn-nv]

@code-asher i've went through the related issue as well, and i wanted to know if you plan to make sub-path routing available OOB:
for example, allow serving on:https://blabla.com/testing/code-server/
instead of the currently expected FQDN: https://code-server.blabla.com/
without configuring reverse-proxy or any 3rd party tools.
This would be a great addition :) i'd be happy to contribute it myself as well, just wanted know your opinion first.

[code-asher]

No plans; at the moment our stance is that a reverse proxy should be used!

But, if you have a compelling argument do let me know. From what I understand, it does not make sense to have this capability in code-server because you would have to listen on port 80/443, which means nothing else can be there, which means you might as well serve at the root anyway? So to use sub-path routing, you really need a reverse proxy to have it make any sense anyway.

[itay-nvn-nv]

@code-asher gotcha

attaching here a deploy+svc+ingress manifest that worked for me when attempting to launch code-server on a sub-path, for future reference:

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: code-server
spec:
  replicas: 1
  selector:
    matchLabels:
      app: code-server
  template:
    metadata:
      labels:
        app: code-server
    spec:
      containers:
      - name: code-server
        image: ghcr.io/coder/code-server:latest
        ports:
        - containerPort: 8080
        env:
        - name: PASSWORD
          value: "your-password-here"
        - name: SUDO_PASSWORD
          value: "your-sudo-password-here"
        - name: BASE_URL
          value: /hello/world
---
apiVersion: v1
kind: Service
metadata:
  name: code-server
spec:
  selector:
    app: code-server
  ports:
  - port: 80
    targetPort: 8080
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: code-server
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/rewrite-target: /$1
spec:
  rules:
  - host: your.domain.com
    http:
      paths:
      - path: /hello/world/?(.*)
        pathType: ImplementationSpecific
        backend:
          service:
            name: code-server
            port:
              number: 80

this will allow to serve your code-server container at https://your.domain.com/hello/world/

[shalldie]

I want to serve code-server on a subpath like /code, but the ci/helm-chart can't edit pathType in values.yaml, which resulting in inability to rewrite.

I think it would be great if it could natively support subpath.