SessionMapper adds properties to your requests based on custom logic. To perform its task, it connects to a Mapping Server that matches sessions to users, groups, roles, experiments, preferences, tracing properties or whatever is needed to provide advanced server-side routing capabilities.

The SessionMapper middleware for Traefik queries an API and set additional headers before it runs upstream requests. The middleware can be used in front of others. It allows advanced behaviors and applications are limitless... The principle is shown below:

SessionMapper can easily be used and adapted for A/B testing, canary deployment, role-based security, advanced tracing, test collection, personalization...

You only need a few parameters to configure the middleware:

• headers lists the headers to capture from the request and send to the server (default: me)
• server is the server URL (default: http://localhost:7777/)
• timeout is the delay in milliseconds before the request to the server fails and no headers are set to the upstream request.

For now, the session Mapper is a simple HTTP server that should be colocated to traefik, for instance as a sidecar. The middleware performs a POST to the server URL. The return message would look like below:

{"upstream": {
	"key1": "value1",
	"key2": "value2"
}}

The server directory that is part of the carnage-sh/sessionmapper provides a simple service that implements the current request/response protocol. Next release will improve the protocol to reduce the latency and make it more reliable, including blocking on failure. Do not hesitate to open an issue if you repository find this plugin useful and want to support more advanced scenarios.