HTTPRoute is a Gateway API type for specifying routing behavior of HTTP requests from a Gateway listener to an API object, i.e. Service.
The specification of an HTTPRoute consists of:
- ParentRefs- Define which Gateways this Route wants to be attached to.
- Hostnames (optional)- Define a list of hostnames to use for matching the Host header of HTTP requests.
- Rules- Define a list of rules to perform actions against matching HTTP requests. Each rule consists of matches, filters (optional), and backendRefs (optional) fields.
The following illustrates an HTTPRoute that sends all traffic to one Service:
Attaching to Gateways¶
Each Route includes a way to reference the parent resources it wants to attach to. In most cases, that's going to be Gateways, but there is some flexibility here for implementations to support other types of parent resources.
The following example shows how a Route would attach to the
apiVersion: gateway.networking.k8s.io/v1beta1 kind: HTTPRoute metadata: name: httproute-example spec: parentRefs: - name: acme-lb
Note that the target Gateway needs to allow HTTPRoutes from the route's namespace to be attached for the attachment to be successful.
Hostnames define a list of hostnames to match against the Host header of the HTTP request. When a match occurs, the HTTPRoute is selected to perform request routing based on rules and filters (optional). A hostname is the fully qualified domain name of a network host, as defined by RFC 3986. Note the following deviations from the “host” part of the URI as defined in the RFC:
- IPs are not allowed.
- The : delimiter is not respected because ports are not allowed.
Incoming requests are matched against hostnames before the HTTPRoute rules are evaluated. If no hostname is specified, traffic is routed based on HTTPRoute rules and filters (optional).
The following example defines hostname "my.example.com":
apiVersion: gateway.networking.k8s.io/v1beta1 kind: HTTPRoute metadata: name: httproute-example spec: hostnames: - my.example.com
Rules define semantics for matching an HTTP request based on conditions, optionally executing additional processing steps, and optionally forwarding the request to an API object.
Matches define conditions used for matching an HTTP request. Each match is independent, i.e. this rule will be matched if any single match is satisfied.
Take the following matches configuration as an example:
apiVersion: gateway.networking.k8s.io/v1beta1 kind: HTTPRoute ... matches: - path: value: "/foo" headers: values: version: "2" - path: value: "/v2/foo"
For a request to match against this rule, it must satisfy EITHER of the following conditions:
- A path prefixed with /foo AND contains the header "version: 2"
- A path prefix of /v2/foo
If no matches are specified, the default is a prefix path match on “/”, which has the effect of matching every HTTP request.
Filters define processing steps that must be completed during the request or response lifecycle. Filters act as an extension point to express additional processing that may be performed in Gateway implementations. Some examples include request or response modification, implementing authentication strategies, rate-limiting, and traffic shaping.
The following example adds header "my-header: foo" to HTTP requests with Host header "my.filter.com".
apiVersion: gateway.networking.k8s.io/v1beta1 kind: HTTPRoute metadata: name: http-filter-1 spec: hostnames: - my.filter.com rules: - filters: - type: RequestHeaderModifier requestHeaderModifier: add: - name: my-header value: foo backendRefs: - name: my-filter-svc1 weight: 1 port: 80
API conformance is defined based on the filter type. The effects of ordering multiple behaviors is currently unspecified. This may change in the future based on feedback during the alpha stage.
Conformance levels are defined by the filter type:
- All "core" filters MUST be supported by implementations.
- Implementers are encouraged to support "extended" filters.
- "Custom" filters have no API guarantees across implementations.
Specifying a core filter multiple times has unspecified or implementation-specific conformance.
All filters are expected to be compatible with each other except for the URLRewrite and RequestRedirect filters, which may not be combined. If an implementation can not support other combinations of filters, they must clearly document that limitation. In all cases where incompatible or unsupported filters are specified, implementations MUST add a warning condition to status.
BackendRefs defines API objects where matching requests should be sent. If unspecified, the rule performs no forwarding. If unspecified and no filters are specified that would result in a response being sent, a 404 error code is returned.
The following example forwards HTTP requests for prefix
/bar to service
"my-service1" on port
8080 and HTTP requests for prefix
magic: foo to service "my-service2" on port
apiVersion: gateway.networking.k8s.io/v1beta1 kind: GatewayClass metadata: name: acme-lb spec: controllerName: acme.io/gateway-controller parametersRef: name: acme-lb group: acme.io kind: Parameters --- apiVersion: gateway.networking.k8s.io/v1beta1 kind: Gateway metadata: name: my-gateway spec: gatewayClassName: acme-lb listeners: # Use GatewayClass defaults for listener definition. - name: http protocol: HTTP port: 80 --- apiVersion: gateway.networking.k8s.io/v1beta1 kind: HTTPRoute metadata: name: http-app-1 spec: parentRefs: - name: my-gateway hostnames: - "foo.com" rules: - matches: - path: type: PathPrefix value: /bar backendRefs: - name: my-service1 port: 8080 - matches: - headers: - type: Exact name: magic value: foo queryParams: - type: Exact name: great value: example path: type: PathPrefix value: /some/thing method: GET backendRefs: - name: my-service2 port: 8080
The following example uses the
weight field to forward 90% of HTTP requests to
foo.example.com to the "foo-v1" Service and the other 10% to the "foo-v2"
apiVersion: gateway.networking.k8s.io/v1beta1 kind: HTTPRoute metadata: name: foo-route labels: gateway: prod-web-gw spec: hostnames: - foo.example.com rules: - backendRefs: - name: foo-v1 port: 8080 weight: 90 - name: foo-v2 port: 8080 weight: 10
Reference the backendRef API documentation for additional details
weight and other fields.
Status defines the observed state of HTTPRoute.
RouteStatus defines the observed state that is required across all route types.
Parents define a list of the Gateways (or other parent resources) that are associated with the HTTPRoute, and the status of the HTTPRoute with respect to each of these Gateways. When a HTTPRoute adds a reference to a Gateway in parentRefs, the controller that manages the Gateway should add an entry to this list when the controller first sees the route and should update the entry as appropriate when the route is modified.
The following example indicates HTTPRoute "http-example" has been accepted by Gateway "gw-example" in namespace "gw-example-ns":
apiVersion: gateway.networking.k8s.io/v1beta1 kind: HTTPRoute metadata: name: http-example ... status: parents: - parentRefs: name: gw-example namespace: gw-example-ns conditions: - type: Accepted status: "True"
Multiple HTTPRoutes can be attached to a single Gateway resource. Importantly, only one Route rule may match each request. For more information on how conflict resolution applies to merging, refer to the API specification.