Routing

A router is in charge of connecting incoming requests to the services that can handle them. In the process, routers may use pieces of middleware to update the request, or act before forwarding the request to the service.

Configuration Examples

Check on the Host using a Regular Expression

apiVersion: traefik.io/v1alpha1
kind: IngressRoute
metadata:
  name: my-app
  namespace: apps
spec:
  entryPoints:
    - websecure
  routes:
    # Match requests with Host set to either example.com or example.org.
    # To match domains case-insensitively, use the (?i) option.
  - match: HostRegexp(`(?i)^example\.(com|org)$`)
    kind: Rule
    services:
    - name: whoami
      port: 80

Check on the Host, add a priority

apiVersion: traefik.io/v1alpha1
kind: IngressRoute
metadata:
  name: my-app
  namespace: apps
spec:
  entryPoints:
    - websecure
  routes:
    # Match requests with Host set to whoami.example.com.
  - match: Host(`whoami.example.com`)
    kind: Rule
    # The bigger the number, the higher the priority
    priority: 10000
    services:
    - name: whoami
      port: 80

Check on the Path, the Method and the Header

apiVersion: traefik.io/v1alpha1
kind: IngressRoute
metadata:
  name: my-app
  namespace: apps
spec:
  entryPoints:
    - websecure
  routes:
    # Match requests with a Content-Type header set to either application/json or application/yaml
    # And a path set to /products but neither /products/shoes nor /products/
    # AND only the HTTP Methods GET, POST and PUT
  - match: Path(`/products`) && HeaderRegexp(`Content-Type`, `^application/(json|yaml)$`) && (Method(`GET`) || Method(`POST`) || Method(`PUT`))
    kind: Rule
    services:
    - name: whoami
      port: 80

Configuring UDP Routers

warning

The character @ is not allowed in the router name

General

Similarly to TCP, as UDP is the transport layer, there is no concept of a request, so there is no notion of an URL path prefix to match an incoming UDP packet with. Furthermore, as there is no good TLS support at the moment for multiple hosts, there is no Host SNI notion to match against either. Therefore, there is no criterion that could be used as a rule to match incoming packets in order to route them. So UDP routers at this time are pretty much only load-balancers in one form or another.

Sessions and timeout

Even though UDP is connectionless (and because of that), the implementation of an UDP router in Traefik relies on what we (and a couple of other implementations) call a session. It means that some state is kept about an ongoing communication between a client and a backend, notably so that the proxy knows where to forward a response packet from a backend. As expected, a timeout is associated to each of these sessions, so that they get cleaned out if they go through a period of inactivity longer than a given duration.

EntryPoints

If not specified, UDP routers will accept packets from all defined UDP EntryPoints. If one wants to limit the router scope to a set of EntryPoints, one should set the entryPoints option.

Listens to Every Entry Point

udp:
  routers:
    Router-1:
      # By default, routers listen to all UDP entrypoints
      # i.e. "other", and "streaming".
      service: "service-1"

Listens to Specific EntryPoints

## Dynamic configuration
udp:
  routers:
    Router-1:
      # does not listen on "other" entry point
      entryPoints:
        - "streaming"
      service: "service-1"

Services

There must be one (and only one) UDP service referenced per UDP router. Services are the target for the router.

note

UDP routers can only target UDP services (and not HTTP or TCP services).