feat: Allow overriding default LLM provider endpoints

api/v1alpha1/ai_backend.go

@@ -21,6 +21,37 @@ type LLMProvider struct {
 	// Send requests to a custom host and port, such as to proxy the request,
 	// or to use a different backend that is API-compliant with the Backend version.
 	HostOverride *Host `json:"hostOverride,omitempty"`
+
+	// TODO: Consolidate all Override options into ProviderOverride.
+	// Overrides the default API path for the LLM provider.
+	// Allows routing requests to a custom API endpoint path.
+	PathOverride *PathOverride `json:"pathOverride,omitempty"`
+
+	// Customizes the Authorization header sent to the LLM provider.
+	// Allows changing the header name and/or the prefix (e.g., "Bearer").
+	// Note: Not all LLM providers use the Authorization header and prefix.
+	// For example, OpenAI uses header: "Authorization" and prefix: "Bearer" But Azure OpenAI uses header: "api-key"
+	//and no Bearer.
+	AuthHeaderOverride *AuthHeaderOverride `json:"authHeaderOverride,omitempty"`
+}
+
+// PathOverride configures the AI gateway to use a custom path for LLM provider chat-completion API requests.
+// It allows overriding the default API path with a custom one.
+// This is useful when you need to route requests to a different API endpoint while maintaining
+// compatibility with the original provider's API structure.
+// +kubebuilder:validation:MinProperties=1
+type PathOverride struct {
+	// FullPath specifies the custom API path to use for the LLM provider requests.
+	// This path will replace the default API path for the provider.
+	FullPath *string `json:"fullPath"`
+}
+
+// AuthHeaderOverride allows customization of the default Authorization header sent to the LLM Provider.
+// The default header is `Authorization: Bearer <token>`. HeaderName can change the Authorization
+// header name and Prefix can change the Bearer prefix
+type AuthHeaderOverride struct {
+	Prefix     *string `json:"prefix,omitempty"`
+	HeaderName *string `json:"headerName,omitempty"`
 }
 
 // SupportedLLMProvider configures the AI gateway to use a single LLM provider backend.

install/helm/kgateway-crds/templates/gateway.kgateway.dev_backends.yaml

@@ -46,6 +46,13 @@ spec:
                 properties:
                   llm:
                     properties:
+                      authHeaderOverride:
+                        properties:
+                          headerName:
+                            type: string
+                          prefix:
+                            type: string
+                        type: object
                       hostOverride:
                         properties:
                           host:
@@ -62,6 +69,14 @@ spec:
                         - host
                         - port
                         type: object
+                      pathOverride:
+                        minProperties: 1
+                        properties:
+                          fullPath:
+                            type: string
+                        required:
+                        - fullPath
+                        type: object
                       provider:
                         maxProperties: 1
                         minProperties: 1
@@ -250,6 +265,13 @@ spec:
                             pool:
                               items:
                                 properties:
+                                  authHeaderOverride:
+                                    properties:
+                                      headerName:
+                                        type: string
+                                      prefix:
+                                        type: string
+                                    type: object
                                   hostOverride:
                                     properties:
                                       host:
@@ -266,6 +288,14 @@ spec:
                                     - host
                                     - port
                                     type: object
+                                  pathOverride:
+                                    minProperties: 1
+                                    properties:
+                                      fullPath:
+                                        type: string
+                                    required:
+                                    - fullPath
+                                    type: object
                                   provider:
                                     maxProperties: 1
                                     minProperties: 1