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Source file src/sigs.k8s.io/gateway-api/apis/v1alpha2/grpcroute_types.go

Documentation: sigs.k8s.io/gateway-api/apis/v1alpha2

     1  /*
     2  Copyright 2022 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package v1alpha2
    18  
    19  import (
    20  	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
    21  
    22  	v1 "sigs.k8s.io/gateway-api/apis/v1"
    23  )
    24  
    25  // +genclient
    26  // +kubebuilder:object:root=true
    27  // +kubebuilder:resource:categories=gateway-api
    28  // +kubebuilder:subresource:status
    29  // +kubebuilder:storageversion
    30  // +kubebuilder:printcolumn:name="Hostnames",type=string,JSONPath=`.spec.hostnames`
    31  // +kubebuilder:printcolumn:name="Age",type=date,JSONPath=`.metadata.creationTimestamp`
    32  
    33  // GRPCRoute provides a way to route gRPC requests. This includes the capability
    34  // to match requests by hostname, gRPC service, gRPC method, or HTTP/2 header.
    35  // Filters can be used to specify additional processing steps. Backends specify
    36  // where matching requests will be routed.
    37  //
    38  // GRPCRoute falls under extended support within the Gateway API. Within the
    39  // following specification, the word "MUST" indicates that an implementation
    40  // supporting GRPCRoute must conform to the indicated requirement, but an
    41  // implementation not supporting this route type need not follow the requirement
    42  // unless explicitly indicated.
    43  //
    44  // Implementations supporting `GRPCRoute` with the `HTTPS` `ProtocolType` MUST
    45  // accept HTTP/2 connections without an initial upgrade from HTTP/1.1, i.e. via
    46  // ALPN. If the implementation does not support this, then it MUST set the
    47  // "Accepted" condition to "False" for the affected listener with a reason of
    48  // "UnsupportedProtocol".  Implementations MAY also accept HTTP/2 connections
    49  // with an upgrade from HTTP/1.
    50  //
    51  // Implementations supporting `GRPCRoute` with the `HTTP` `ProtocolType` MUST
    52  // support HTTP/2 over cleartext TCP (h2c,
    53  // https://www.rfc-editor.org/rfc/rfc7540#section-3.1) without an initial
    54  // upgrade from HTTP/1.1, i.e. with prior knowledge
    55  // (https://www.rfc-editor.org/rfc/rfc7540#section-3.4). If the implementation
    56  // does not support this, then it MUST set the "Accepted" condition to "False"
    57  // for the affected listener with a reason of "UnsupportedProtocol".
    58  // Implementations MAY also accept HTTP/2 connections with an upgrade from
    59  // HTTP/1, i.e. without prior knowledge.
    60  type GRPCRoute struct {
    61  	metav1.TypeMeta   `json:",inline"`
    62  	metav1.ObjectMeta `json:"metadata,omitempty"`
    63  
    64  	// Spec defines the desired state of GRPCRoute.
    65  	Spec GRPCRouteSpec `json:"spec,omitempty"`
    66  
    67  	// Status defines the current state of GRPCRoute.
    68  	Status GRPCRouteStatus `json:"status,omitempty"`
    69  }
    70  
    71  // +kubebuilder:object:root=true
    72  
    73  // GRPCRouteList contains a list of GRPCRoute.
    74  type GRPCRouteList struct {
    75  	metav1.TypeMeta `json:",inline"`
    76  	metav1.ListMeta `json:"metadata,omitempty"`
    77  	Items           []GRPCRoute `json:"items"`
    78  }
    79  
    80  // GRPCRouteStatus defines the observed state of GRPCRoute.
    81  type GRPCRouteStatus struct {
    82  	RouteStatus `json:",inline"`
    83  }
    84  
    85  // GRPCRouteSpec defines the desired state of GRPCRoute
    86  type GRPCRouteSpec struct {
    87  	CommonRouteSpec `json:",inline"`
    88  
    89  	// Hostnames defines a set of hostnames to match against the GRPC
    90  	// Host header to select a GRPCRoute to process the request. This matches
    91  	// the RFC 1123 definition of a hostname with 2 notable exceptions:
    92  	//
    93  	// 1. IPs are not allowed.
    94  	// 2. A hostname may be prefixed with a wildcard label (`*.`). The wildcard
    95  	//    label MUST appear by itself as the first label.
    96  	//
    97  	// If a hostname is specified by both the Listener and GRPCRoute, there
    98  	// MUST be at least one intersecting hostname for the GRPCRoute to be
    99  	// attached to the Listener. For example:
   100  	//
   101  	// * A Listener with `test.example.com` as the hostname matches GRPCRoutes
   102  	//   that have either not specified any hostnames, or have specified at
   103  	//   least one of `test.example.com` or `*.example.com`.
   104  	// * A Listener with `*.example.com` as the hostname matches GRPCRoutes
   105  	//   that have either not specified any hostnames or have specified at least
   106  	//   one hostname that matches the Listener hostname. For example,
   107  	//   `test.example.com` and `*.example.com` would both match. On the other
   108  	//   hand, `example.com` and `test.example.net` would not match.
   109  	//
   110  	// Hostnames that are prefixed with a wildcard label (`*.`) are interpreted
   111  	// as a suffix match. That means that a match for `*.example.com` would match
   112  	// both `test.example.com`, and `foo.test.example.com`, but not `example.com`.
   113  	//
   114  	// If both the Listener and GRPCRoute have specified hostnames, any
   115  	// GRPCRoute hostnames that do not match the Listener hostname MUST be
   116  	// ignored. For example, if a Listener specified `*.example.com`, and the
   117  	// GRPCRoute specified `test.example.com` and `test.example.net`,
   118  	// `test.example.net` MUST NOT be considered for a match.
   119  	//
   120  	// If both the Listener and GRPCRoute have specified hostnames, and none
   121  	// match with the criteria above, then the GRPCRoute MUST NOT be accepted by
   122  	// the implementation. The implementation MUST raise an 'Accepted' Condition
   123  	// with a status of `False` in the corresponding RouteParentStatus.
   124  	//
   125  	// If a Route (A) of type HTTPRoute or GRPCRoute is attached to a
   126  	// Listener and that listener already has another Route (B) of the other
   127  	// type attached and the intersection of the hostnames of A and B is
   128  	// non-empty, then the implementation MUST accept exactly one of these two
   129  	// routes, determined by the following criteria, in order:
   130  	//
   131  	// * The oldest Route based on creation timestamp.
   132  	// * The Route appearing first in alphabetical order by
   133  	//   "{namespace}/{name}".
   134  	//
   135  	// The rejected Route MUST raise an 'Accepted' condition with a status of
   136  	// 'False' in the corresponding RouteParentStatus.
   137  	//
   138  	// Support: Core
   139  	//
   140  	// +optional
   141  	// +kubebuilder:validation:MaxItems=16
   142  	Hostnames []Hostname `json:"hostnames,omitempty"`
   143  
   144  	// Rules are a list of GRPC matchers, filters and actions.
   145  	//
   146  	// +optional
   147  	// +kubebuilder:validation:MaxItems=16
   148  	Rules []GRPCRouteRule `json:"rules,omitempty"`
   149  }
   150  
   151  // GRPCRouteRule defines the semantics for matching a gRPC request based on
   152  // conditions (matches), processing it (filters), and forwarding the request to
   153  // an API object (backendRefs).
   154  type GRPCRouteRule struct {
   155  	// Matches define conditions used for matching the rule against incoming
   156  	// gRPC requests. Each match is independent, i.e. this rule will be matched
   157  	// if **any** one of the matches is satisfied.
   158  	//
   159  	// For example, take the following matches configuration:
   160  	//
   161  	// ```
   162  	// matches:
   163  	// - method:
   164  	//     service: foo.bar
   165  	//   headers:
   166  	//     values:
   167  	//       version: 2
   168  	// - method:
   169  	//     service: foo.bar.v2
   170  	// ```
   171  	//
   172  	// For a request to match against this rule, it MUST satisfy
   173  	// EITHER of the two conditions:
   174  	//
   175  	// - service of foo.bar AND contains the header `version: 2`
   176  	// - service of foo.bar.v2
   177  	//
   178  	// See the documentation for GRPCRouteMatch on how to specify multiple
   179  	// match conditions to be ANDed together.
   180  	//
   181  	// If no matches are specified, the implementation MUST match every gRPC request.
   182  	//
   183  	// Proxy or Load Balancer routing configuration generated from GRPCRoutes
   184  	// MUST prioritize rules based on the following criteria, continuing on
   185  	// ties. Merging MUST not be done between GRPCRoutes and HTTPRoutes.
   186  	// Precedence MUST be given to the rule with the largest number of:
   187  	//
   188  	// * Characters in a matching non-wildcard hostname.
   189  	// * Characters in a matching hostname.
   190  	// * Characters in a matching service.
   191  	// * Characters in a matching method.
   192  	// * Header matches.
   193  	//
   194  	// If ties still exist across multiple Routes, matching precedence MUST be
   195  	// determined in order of the following criteria, continuing on ties:
   196  	//
   197  	// * The oldest Route based on creation timestamp.
   198  	// * The Route appearing first in alphabetical order by
   199  	//   "{namespace}/{name}".
   200  	//
   201  	// If ties still exist within the Route that has been given precedence,
   202  	// matching precedence MUST be granted to the first matching rule meeting
   203  	// the above criteria.
   204  	//
   205  	// +optional
   206  	// +kubebuilder:validation:MaxItems=8
   207  	Matches []GRPCRouteMatch `json:"matches,omitempty"`
   208  
   209  	// Filters define the filters that are applied to requests that match
   210  	// this rule.
   211  	//
   212  	// The effects of ordering of multiple behaviors are currently unspecified.
   213  	// This can change in the future based on feedback during the alpha stage.
   214  	//
   215  	// Conformance-levels at this level are defined based on the type of filter:
   216  	//
   217  	// - ALL core filters MUST be supported by all implementations that support
   218  	//   GRPCRoute.
   219  	// - Implementers are encouraged to support extended filters.
   220  	// - Implementation-specific custom filters have no API guarantees across
   221  	//   implementations.
   222  	//
   223  	// Specifying the same filter multiple times is not supported unless explicitly
   224  	// indicated in the filter.
   225  	//
   226  	// If an implementation can not support a combination of filters, it must clearly
   227  	// document that limitation. In cases where incompatible or unsupported
   228  	// filters are specified and cause the `Accepted` condition to be set to status
   229  	// `False`, implementations may use the `IncompatibleFilters` reason to specify
   230  	// this configuration error.
   231  	//
   232  	// Support: Core
   233  	//
   234  	// +optional
   235  	// +kubebuilder:validation:MaxItems=16
   236  	// +kubebuilder:validation:XValidation:message="RequestHeaderModifier filter cannot be repeated",rule="self.filter(f, f.type == 'RequestHeaderModifier').size() <= 1"
   237  	// +kubebuilder:validation:XValidation:message="ResponseHeaderModifier filter cannot be repeated",rule="self.filter(f, f.type == 'ResponseHeaderModifier').size() <= 1"
   238  	Filters []GRPCRouteFilter `json:"filters,omitempty"`
   239  
   240  	// BackendRefs defines the backend(s) where matching requests should be
   241  	// sent.
   242  	//
   243  	// Failure behavior here depends on how many BackendRefs are specified and
   244  	// how many are invalid.
   245  	//
   246  	// If *all* entries in BackendRefs are invalid, and there are also no filters
   247  	// specified in this route rule, *all* traffic which matches this rule MUST
   248  	// receive an `UNAVAILABLE` status.
   249  	//
   250  	// See the GRPCBackendRef definition for the rules about what makes a single
   251  	// GRPCBackendRef invalid.
   252  	//
   253  	// When a GRPCBackendRef is invalid, `UNAVAILABLE` statuses MUST be returned for
   254  	// requests that would have otherwise been routed to an invalid backend. If
   255  	// multiple backends are specified, and some are invalid, the proportion of
   256  	// requests that would otherwise have been routed to an invalid backend
   257  	// MUST receive an `UNAVAILABLE` status.
   258  	//
   259  	// For example, if two backends are specified with equal weights, and one is
   260  	// invalid, 50 percent of traffic MUST receive an `UNAVAILABLE` status.
   261  	// Implementations may choose how that 50 percent is determined.
   262  	//
   263  	// Support: Core for Kubernetes Service
   264  	//
   265  	// Support: Implementation-specific for any other resource
   266  	//
   267  	// Support for weight: Core
   268  	//
   269  	// +optional
   270  	// +kubebuilder:validation:MaxItems=16
   271  	BackendRefs []GRPCBackendRef `json:"backendRefs,omitempty"`
   272  }
   273  
   274  // GRPCRouteMatch defines the predicate used to match requests to a given
   275  // action. Multiple match types are ANDed together, i.e. the match will
   276  // evaluate to true only if all conditions are satisfied.
   277  //
   278  // For example, the match below will match a gRPC request only if its service
   279  // is `foo` AND it contains the `version: v1` header:
   280  //
   281  // ```
   282  // matches:
   283  //   - method:
   284  //     type: Exact
   285  //     service: "foo"
   286  //     headers:
   287  //   - name: "version"
   288  //     value "v1"
   289  //
   290  // ```
   291  type GRPCRouteMatch struct {
   292  	// Method specifies a gRPC request service/method matcher. If this field is
   293  	// not specified, all services and methods will match.
   294  	//
   295  	// +optional
   296  	Method *GRPCMethodMatch `json:"method,omitempty"`
   297  
   298  	// Headers specifies gRPC request header matchers. Multiple match values are
   299  	// ANDed together, meaning, a request MUST match all the specified headers
   300  	// to select the route.
   301  	//
   302  	// +listType=map
   303  	// +listMapKey=name
   304  	// +optional
   305  	// +kubebuilder:validation:MaxItems=16
   306  	Headers []GRPCHeaderMatch `json:"headers,omitempty"`
   307  }
   308  
   309  // GRPCMethodMatch describes how to select a gRPC route by matching the gRPC
   310  // request service and/or method.
   311  //
   312  // At least one of Service and Method MUST be a non-empty string.
   313  //
   314  // +kubebuilder:validation:XValidation:message="One or both of 'service' or 'method' must be specified",rule="has(self.type) ? has(self.service) || has(self.method) : true"
   315  // +kubebuilder:validation:XValidation:message="service must only contain valid characters (matching ^(?i)\\.?[a-z_][a-z_0-9]*(\\.[a-z_][a-z_0-9]*)*$)",rule="(!has(self.type) || self.type == 'Exact') && has(self.service) ? self.service.matches(r\"\"\"^(?i)\\.?[a-z_][a-z_0-9]*(\\.[a-z_][a-z_0-9]*)*$\"\"\"): true"
   316  // +kubebuilder:validation:XValidation:message="method must only contain valid characters (matching ^[A-Za-z_][A-Za-z_0-9]*$)",rule="(!has(self.type) || self.type == 'Exact') && has(self.method) ? self.method.matches(r\"\"\"^[A-Za-z_][A-Za-z_0-9]*$\"\"\"): true"
   317  type GRPCMethodMatch struct {
   318  	// Type specifies how to match against the service and/or method.
   319  	// Support: Core (Exact with service and method specified)
   320  	//
   321  	// Support: Implementation-specific (Exact with method specified but no service specified)
   322  	//
   323  	// Support: Implementation-specific (RegularExpression)
   324  	//
   325  	// +optional
   326  	// +kubebuilder:default=Exact
   327  	Type *GRPCMethodMatchType `json:"type,omitempty"`
   328  
   329  	// Value of the service to match against. If left empty or omitted, will
   330  	// match any service.
   331  	//
   332  	// At least one of Service and Method MUST be a non-empty string.
   333  	//
   334  	// +optional
   335  	// +kubebuilder:validation:MaxLength=1024
   336  	Service *string `json:"service,omitempty"`
   337  
   338  	// Value of the method to match against. If left empty or omitted, will
   339  	// match all services.
   340  	//
   341  	// At least one of Service and Method MUST be a non-empty string.
   342  	//
   343  	// +optional
   344  	// +kubebuilder:validation:MaxLength=1024
   345  	Method *string `json:"method,omitempty"`
   346  }
   347  
   348  // MethodMatchType specifies the semantics of how gRPC methods and services are compared.
   349  // Valid MethodMatchType values, along with their conformance levels, are:
   350  //
   351  // * "Exact" - Core
   352  // * "RegularExpression" - Implementation Specific
   353  //
   354  // Exact methods MUST be syntactically valid:
   355  //
   356  // - Must not contain `/` character
   357  //
   358  // +kubebuilder:validation:Enum=Exact;RegularExpression
   359  type GRPCMethodMatchType string
   360  
   361  const (
   362  	// Matches the method or service exactly and with case sensitivity.
   363  	GRPCMethodMatchExact GRPCMethodMatchType = "Exact"
   364  
   365  	// Matches if the method or service matches the given regular expression with
   366  	// case sensitivity.
   367  	//
   368  	// Since `"RegularExpression"` has implementation-specific conformance,
   369  	// implementations can support POSIX, PCRE, RE2 or any other regular expression
   370  	// dialect.
   371  	// Please read the implementation's documentation to determine the supported
   372  	// dialect.
   373  	GRPCMethodMatchRegularExpression GRPCMethodMatchType = "RegularExpression"
   374  )
   375  
   376  // GRPCHeaderMatch describes how to select a gRPC route by matching gRPC request
   377  // headers.
   378  type GRPCHeaderMatch struct {
   379  	// Type specifies how to match against the value of the header.
   380  	//
   381  	// +optional
   382  	// +kubebuilder:default=Exact
   383  	Type *HeaderMatchType `json:"type,omitempty"`
   384  
   385  	// Name is the name of the gRPC Header to be matched.
   386  	//
   387  	// If multiple entries specify equivalent header names, only the first
   388  	// entry with an equivalent name MUST be considered for a match. Subsequent
   389  	// entries with an equivalent header name MUST be ignored. Due to the
   390  	// case-insensitivity of header names, "foo" and "Foo" are considered
   391  	// equivalent.
   392  	Name GRPCHeaderName `json:"name"`
   393  
   394  	// Value is the value of the gRPC Header to be matched.
   395  	//
   396  	// +kubebuilder:validation:MinLength=1
   397  	// +kubebuilder:validation:MaxLength=4096
   398  	Value string `json:"value"`
   399  }
   400  
   401  // GRPCHeaderMatchType specifies the semantics of how GRPC header values should
   402  // be compared. Valid GRPCHeaderMatchType values, along with their conformance
   403  // levels, are:
   404  //
   405  // * "Exact" - Core
   406  // * "RegularExpression" - Implementation Specific
   407  //
   408  // Note that new values may be added to this enum in future releases of the API,
   409  // implementations MUST ensure that unknown values will not cause a crash.
   410  //
   411  // Unknown values here MUST result in the implementation setting the Accepted
   412  // Condition for the Route to `status: False`, with a Reason of
   413  // `UnsupportedValue`.
   414  //
   415  // +kubebuilder:validation:Enum=Exact;RegularExpression
   416  type GRPCHeaderMatchType string
   417  
   418  // GRPCHeaderMatchType constants.
   419  const (
   420  	GRPCHeaderMatchExact             GRPCHeaderMatchType = "Exact"
   421  	GRPCHeaderMatchRegularExpression GRPCHeaderMatchType = "RegularExpression"
   422  )
   423  
   424  type GRPCHeaderName v1.HeaderName
   425  
   426  // GRPCRouteFilterType identifies a type of GRPCRoute filter.
   427  type GRPCRouteFilterType string
   428  
   429  const (
   430  	// GRPCRouteFilterRequestHeaderModifier can be used to add or remove a gRPC
   431  	// header from a gRPC request before it is sent to the upstream target.
   432  	//
   433  	// Support in GRPCRouteRule: Core
   434  	//
   435  	// Support in GRPCBackendRef: Extended
   436  	GRPCRouteFilterRequestHeaderModifier GRPCRouteFilterType = "RequestHeaderModifier"
   437  
   438  	// GRPCRouteFilterRequestHeaderModifier can be used to add or remove a gRPC
   439  	// header from a gRPC response before it is sent to the client.
   440  	//
   441  	// Support in GRPCRouteRule: Core
   442  	//
   443  	// Support in GRPCBackendRef: Extended
   444  	GRPCRouteFilterResponseHeaderModifier GRPCRouteFilterType = "ResponseHeaderModifier"
   445  
   446  	// GRPCRouteFilterRequestMirror can be used to mirror gRPC requests to a
   447  	// different backend. The responses from this backend MUST be ignored by
   448  	// the Gateway.
   449  	//
   450  	// Support in GRPCRouteRule: Extended
   451  	//
   452  	// Support in GRPCBackendRef: Extended
   453  	GRPCRouteFilterRequestMirror GRPCRouteFilterType = "RequestMirror"
   454  
   455  	// GRPCRouteFilterExtensionRef should be used for configuring custom
   456  	// gRPC filters.
   457  	//
   458  	// Support in GRPCRouteRule: Implementation-specific
   459  	//
   460  	// Support in GRPCBackendRef: Implementation-specific
   461  	GRPCRouteFilterExtensionRef GRPCRouteFilterType = "ExtensionRef"
   462  )
   463  
   464  // GRPCRouteFilter defines processing steps that must be completed during the
   465  // request or response lifecycle. GRPCRouteFilters are meant as an extension
   466  // point to express processing that may be done in Gateway implementations. Some
   467  // examples include request or response modification, implementing
   468  // authentication strategies, rate-limiting, and traffic shaping. API
   469  // guarantee/conformance is defined based on the type of the filter.
   470  //
   471  // +kubebuilder:validation:XValidation:message="filter.requestHeaderModifier must be nil if the filter.type is not RequestHeaderModifier",rule="!(has(self.requestHeaderModifier) && self.type != 'RequestHeaderModifier')"
   472  // +kubebuilder:validation:XValidation:message="filter.requestHeaderModifier must be specified for RequestHeaderModifier filter.type",rule="!(!has(self.requestHeaderModifier) && self.type == 'RequestHeaderModifier')"
   473  // +kubebuilder:validation:XValidation:message="filter.responseHeaderModifier must be nil if the filter.type is not ResponseHeaderModifier",rule="!(has(self.responseHeaderModifier) && self.type != 'ResponseHeaderModifier')"
   474  // +kubebuilder:validation:XValidation:message="filter.responseHeaderModifier must be specified for ResponseHeaderModifier filter.type",rule="!(!has(self.responseHeaderModifier) && self.type == 'ResponseHeaderModifier')"
   475  // +kubebuilder:validation:XValidation:message="filter.requestMirror must be nil if the filter.type is not RequestMirror",rule="!(has(self.requestMirror) && self.type != 'RequestMirror')"
   476  // +kubebuilder:validation:XValidation:message="filter.requestMirror must be specified for RequestMirror filter.type",rule="!(!has(self.requestMirror) && self.type == 'RequestMirror')"
   477  // +kubebuilder:validation:XValidation:message="filter.extensionRef must be nil if the filter.type is not ExtensionRef",rule="!(has(self.extensionRef) && self.type != 'ExtensionRef')"
   478  // +kubebuilder:validation:XValidation:message="filter.extensionRef must be specified for ExtensionRef filter.type",rule="!(!has(self.extensionRef) && self.type == 'ExtensionRef')"
   479  type GRPCRouteFilter struct {
   480  	// Type identifies the type of filter to apply. As with other API fields,
   481  	// types are classified into three conformance levels:
   482  	//
   483  	// - Core: Filter types and their corresponding configuration defined by
   484  	//   "Support: Core" in this package, e.g. "RequestHeaderModifier". All
   485  	//   implementations supporting GRPCRoute MUST support core filters.
   486  	//
   487  	// - Extended: Filter types and their corresponding configuration defined by
   488  	//   "Support: Extended" in this package, e.g. "RequestMirror". Implementers
   489  	//   are encouraged to support extended filters.
   490  	//
   491  	// - Implementation-specific: Filters that are defined and supported by specific vendors.
   492  	//   In the future, filters showing convergence in behavior across multiple
   493  	//   implementations will be considered for inclusion in extended or core
   494  	//   conformance levels. Filter-specific configuration for such filters
   495  	//   is specified using the ExtensionRef field. `Type` MUST be set to
   496  	//   "ExtensionRef" for custom filters.
   497  	//
   498  	// Implementers are encouraged to define custom implementation types to
   499  	// extend the core API with implementation-specific behavior.
   500  	//
   501  	// If a reference to a custom filter type cannot be resolved, the filter
   502  	// MUST NOT be skipped. Instead, requests that would have been processed by
   503  	// that filter MUST receive a HTTP error response.
   504  	//
   505  	// +unionDiscriminator
   506  	// +kubebuilder:validation:Enum=ResponseHeaderModifier;RequestHeaderModifier;RequestMirror;ExtensionRef
   507  	// <gateway:experimental:validation:Enum=ResponseHeaderModifier;RequestHeaderModifier;RequestMirror;ExtensionRef>
   508  	Type GRPCRouteFilterType `json:"type"`
   509  
   510  	// RequestHeaderModifier defines a schema for a filter that modifies request
   511  	// headers.
   512  	//
   513  	// Support: Core
   514  	//
   515  	// +optional
   516  	RequestHeaderModifier *HTTPHeaderFilter `json:"requestHeaderModifier,omitempty"`
   517  
   518  	// ResponseHeaderModifier defines a schema for a filter that modifies response
   519  	// headers.
   520  	//
   521  	// Support: Extended
   522  	//
   523  	// +optional
   524  	ResponseHeaderModifier *HTTPHeaderFilter `json:"responseHeaderModifier,omitempty"`
   525  
   526  	// RequestMirror defines a schema for a filter that mirrors requests.
   527  	// Requests are sent to the specified destination, but responses from
   528  	// that destination are ignored.
   529  	//
   530  	// This filter can be used multiple times within the same rule. Note that
   531  	// not all implementations will be able to support mirroring to multiple
   532  	// backends.
   533  	//
   534  	// Support: Extended
   535  	//
   536  	// +optional
   537  	RequestMirror *HTTPRequestMirrorFilter `json:"requestMirror,omitempty"`
   538  
   539  	// ExtensionRef is an optional, implementation-specific extension to the
   540  	// "filter" behavior.  For example, resource "myroutefilter" in group
   541  	// "networking.example.net"). ExtensionRef MUST NOT be used for core and
   542  	// extended filters.
   543  	//
   544  	// Support: Implementation-specific
   545  	//
   546  	// This filter can be used multiple times within the same rule.
   547  	// +optional
   548  	ExtensionRef *LocalObjectReference `json:"extensionRef,omitempty"`
   549  }
   550  
   551  // GRPCBackendRef defines how a GRPCRoute forwards a gRPC request.
   552  //
   553  // Note that when a namespace different than the local namespace is specified, a
   554  // ReferenceGrant object is required in the referent namespace to allow that
   555  // namespace's owner to accept the reference. See the ReferenceGrant
   556  // documentation for details.
   557  //
   558  // <gateway:experimental:description>
   559  //
   560  // When the BackendRef points to a Kubernetes Service, implementations SHOULD
   561  // honor the appProtocol field if it is set for the target Service Port.
   562  //
   563  // Implementations supporting appProtocol SHOULD recognize the Kubernetes
   564  // Standard Application Protocols defined in KEP-3726.
   565  //
   566  // If a Service appProtocol isn't specified, an implementation MAY infer the
   567  // backend protocol through its own means. Implementations MAY infer the
   568  // protocol from the Route type referring to the backend Service.
   569  //
   570  // If a Route is not able to send traffic to the backend using the specified
   571  // protocol then the backend is considered invalid. Implementations MUST set the
   572  // "ResolvedRefs" condition to "False" with the "UnsupportedProtocol" reason.
   573  //
   574  // </gateway:experimental:description>
   575  type GRPCBackendRef struct {
   576  	// BackendRef is a reference to a backend to forward matched requests to.
   577  	//
   578  	// A BackendRef can be invalid for the following reasons. In all cases, the
   579  	// implementation MUST ensure the `ResolvedRefs` Condition on the Route
   580  	// is set to `status: False`, with a Reason and Message that indicate
   581  	// what is the cause of the error.
   582  	//
   583  	// A BackendRef is invalid if:
   584  	//
   585  	// * It refers to an unknown or unsupported kind of resource. In this
   586  	//   case, the Reason MUST be set to `InvalidKind` and Message of the
   587  	//   Condition MUST explain which kind of resource is unknown or unsupported.
   588  	//
   589  	// * It refers to a resource that does not exist. In this case, the Reason MUST
   590  	//   be set to `BackendNotFound` and the Message of the Condition MUST explain
   591  	//   which resource does not exist.
   592  	//
   593  	// * It refers a resource in another namespace when the reference has not been
   594  	//   explicitly allowed by a ReferenceGrant (or equivalent concept). In this
   595  	//   case, the Reason MUST be set to `RefNotPermitted` and the Message of the
   596  	//   Condition MUST explain which cross-namespace reference is not allowed.
   597  	//
   598  	// Support: Core for Kubernetes Service
   599  	//
   600  	// Support: Extended for Kubernetes ServiceImport
   601  	//
   602  	// Support: Implementation-specific for any other resource
   603  	//
   604  	// Support for weight: Core
   605  	//
   606  	// +optional
   607  	BackendRef `json:",inline"`
   608  
   609  	// Filters defined at this level MUST be executed if and only if the
   610  	// request is being forwarded to the backend defined here.
   611  	//
   612  	// Support: Implementation-specific (For broader support of filters, use the
   613  	// Filters field in GRPCRouteRule.)
   614  	//
   615  	// +optional
   616  	// +kubebuilder:validation:MaxItems=16
   617  	// +kubebuilder:validation:XValidation:message="RequestHeaderModifier filter cannot be repeated",rule="self.filter(f, f.type == 'RequestHeaderModifier').size() <= 1"
   618  	// +kubebuilder:validation:XValidation:message="ResponseHeaderModifier filter cannot be repeated",rule="self.filter(f, f.type == 'ResponseHeaderModifier').size() <= 1"
   619  	Filters []GRPCRouteFilter `json:"filters,omitempty"`
   620  }
   621  

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