Middlewares

Tweaking the Request

Attached to the routers, pieces of middleware are a means of tweaking the requests before they are sent to your service (or before the answer from the services are sent to the clients).

There are several available middleware in Traefik, some can modify the request, the headers, some are in charge of redirections, some add authentication, and so on.

Pieces of middleware can be combined in chains to fit every scenario.

Provider Namespace

Be aware of the concept of Providers Namespace described in the Configuration Discovery section. It also applies to Middlewares.

Configuration Example

Docker

# As a Docker Label
whoami:
  #  A container that exposes an API to show its IP address
  image: traefik/whoami
  labels:
    # Create a middleware named `foo-add-prefix`
    - "traefik.http.middlewares.foo-add-prefix.addprefix.prefix=/foo"
    # Apply the middleware named `foo-add-prefix` to the router named `router1`
    - "traefik.http.routers.router1.middlewares=foo-add-prefix@docker"

Kubernetes IngressRoute

# As a Kubernetes Traefik IngressRoute
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: middlewares.traefik.containo.us
spec:
  group: traefik.containo.us
  version: v1alpha1
  names:
    kind: Middleware
    plural: middlewares
    singular: middleware
  scope: Namespaced

---
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: stripprefix
spec:
  stripPrefix:
    prefixes:
      - /stripit

---
apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
  name: ingressroute
spec:
# more fields...
  routes:
    # more fields...
    middlewares:
      - name: stripprefix

Consul Catalog

# Create a middleware named `foo-add-prefix`
- "traefik.http.middlewares.foo-add-prefix.addprefix.prefix=/foo"
# Apply the middleware named `foo-add-prefix` to the router named `router1`
- "traefik.http.routers.router1.middlewares=foo-add-prefix@consulcatalog"

Marathon

"labels": {
  "traefik.http.middlewares.foo-add-prefix.addprefix.prefix": "/foo",
  "traefik.http.routers.router1.middlewares": "foo-add-prefix@marathon"
}

Rancher

# As a Rancher Label
labels:
  # Create a middleware named `foo-add-prefix`
  - "traefik.http.middlewares.foo-add-prefix.addprefix.prefix=/foo"
  # Apply the middleware named `foo-add-prefix` to the router named `router1`
  - "traefik.http.routers.router1.middlewares=foo-add-prefix@rancher"

File (YAML)

# As YAML Configuration File
http:
  routers:
    router1:
      service: myService
      middlewares:
        - "foo-add-prefix"
      rule: "Host(`example.com`)"

  middlewares:
    foo-add-prefix:
      addPrefix:
        prefix: "/foo"

  services:
    service1:
      loadBalancer:
        servers:
          - url: "http://127.0.0.1:80"

File (TOML)

# As TOML Configuration File
[http.routers]
  [http.routers.router1]
    service = "myService"
    middlewares = ["foo-add-prefix"]
    rule = "Host(`example.com`)"

[http.middlewares]
  [http.middlewares.foo-add-prefix.addPrefix]
    prefix = "/foo"

[http.services]
  [http.services.service1]
    [http.services.service1.loadBalancer]

      [[http.services.service1.loadBalancer.servers]]
        url = "http://127.0.0.1:80"

Available Middlewares

Middleware	Purpose	Area
AddPrefix	Add a Path Prefix	Path Modifier
BasicAuth	Basic auth mechanism	Security, Authentication
Buffering	Buffers the request/response	Request Lifecycle
Chain	Combine multiple pieces of middleware	Middleware tool
CircuitBreaker	Stop calling unhealthy services	Request Lifecycle
Compress	Compress the response	Content Modifier
DigestAuth	Adds Digest Authentication	Security, Authentication
Errors	Define custom error pages	Request Lifecycle
ForwardAuth	Authentication delegation	Security, Authentication
Headers	Add / Update headers	Security
IPWhiteList	Limit the allowed client IPs	Security, Request lifecycle
InFlightReq	Limit the number of simultaneous connections	Security, Request lifecycle
PassTLSClientCert	Adding Client Certificates in a Header	Security
RateLimit	Limit the call frequency	Security, Request lifecycle
RedirectScheme	Redirect easily the client elsewhere	Request lifecycle
RedirectRegex	Redirect the client elsewhere	Request lifecycle
ReplacePath	Change the path of the request	Path Modifier
ReplacePathRegex	Change the path of the request	Path Modifier
Retry	Automatically retry the request in case of errors	Request lifecycle
StripPrefix	Change the path of the request	Path Modifier
StripPrefixRegex	Change the path of the request	Path Modifier