Middlewares

Tweaking the Request

Overview

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

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

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