Traefik OpenFeature plugin

The plugin take header from request and evaluate the configuration feature flag against an Open Feature compliance backend. Then, forward the request to downstream service with enrich header

Usage

Configuration

For each plugin, the Traefik static configuration must define the module name (as is usual for Go packages).

The following declaration (given here in YAML) defines a plugin:

# Static configuration

experimental:
  plugins:
    openfeatures:
      moduleName: github.com/dzungtr/traefik-openfeatures
      version: v0.0.1

Here is an example of a file provider dynamic configuration (given here in YAML), where the interesting part is the http.middlewares section:

# Dynamic configuration

http:
  routers:
    my-router:
      rule: host(`demo.localhost`)
      service: service-foo
      entryPoints:
        - web
      middlewares:
        - check-featureflag

  services:
   service-foo:
      loadBalancer:
        servers:
          - url: http://127.0.0.1:5000
  
  middlewares:
    check-featureflag:
      plugin:
        openfeatures:
          Endpoint: http://host.internal.docker:9000
          Provider: flipt
          ContextHeaderKeys:
            - organization
            - user
          Service: my-service
          UserHeader: user
          FeatureHeaderPrefix: openfeature_
          Flags:
          # get value for flag
            api_version: string
            enable_check: bool
          # the request to to downstream service will have headers
          # openfeature_api_version: "some-version"
          # openfeature_enable_check: "false" 

Reference

Key	Type	Description	Example
Endpoint	string	OpenFeature Backend url	http://host.internal.docker:9000
Authorization	string	authorization header to use with feature backend	Bearer <token>
Provider	string	OpenFeature provider	flipt, noop
ContextHeaderKeys	[]string	The header taken for context evaluation	organization, user
Service	string	Name of service	my-service>
UserHeader	string	The name of header used to extract user identifier	x-user-id
FeatureHeaderPrefix	string	The header's prefix for flag attatching to request to downstream service	openfeature_
Flags	{ <flag>: <type> }	list of flag to evaluate in open feature backend	api_version: string|int|float|bool|object