Header rewrite Traefik plugin

Traefik plugin that can modify http headers.

Motivation

This project was created because openshift/oauth-proxy can't put OpenShift token into Authorization header for the upstream application, where we need it for kube-rbac-proxy to work properly. It can only put it into X-Forwarded-Access-Token header and thus we need this plugin to take the token from X-Forwarded-Access-Token and set it into Authorization header with Bearer prefix.

Note: Upstream oauth2-proxy can do what we need, so we don't need this component on Kubernetes. Some guys has made an effort to port this feature into OpenShift fork, but it was rejected.

Configuration

Traefik static configuration for local plugin:

...
experimental:
  localPlugins:
    header-rewrite:
      moduleName: github.com/che-incubator/header-rewrite-traefik-plugin

Plugin is then configured as a route middleware

http:
  routers:
    route1:
      middlewares: ["headerRewrite"]
  middlewares:
    headerRewrite:
      plugin:
        header-rewrite:
          from: X-Forwarded-Access-Token
          to: Authorization
          prefix: 'Bearer '
          keepOriginal: false
          keepOriginalTarget: true

In this example, when there is X-Forwarded-Access-Token header, it's values will be moved into Authorization header with Bearer as a value prefix. The X-Forwarded-Access-Token header will be removed (keepOriginal: false) and if there were any values in Authorization header, they will stay there (keepOriginalTarget: true).