feat: make prefix of endpoints configurable

cmd/controller/main.go

@@ -50,6 +50,7 @@ type flags struct {
 	metricsRequestHeaderAttributes string
 	metricsRequestHeaderLabels     string // DEPRECATED: use metricsRequestHeaderAttributes instead.
 	spanRequestHeaderAttributes    string
+	endpointPrefixes               string
 	rootPrefix                     string
 	extProcExtraEnvVars            string
 	extProcImagePullSecrets        string
@@ -154,6 +155,11 @@ func parseAndValidateFlags(args []string) (flags, error) {
 		"",
 		"Comma-separated key-value pairs for mapping HTTP request headers to otel span attributes. Format: x-session-id:session.id,x-user-id:user.id.",
 	)
+	endpointPrefixes := fs.String(
+		"endpointPrefixes",
+		"",
+		"Comma-separated key-value pairs for endpoint prefixes. Format: openai:/,cohere:/cohere,anthropic:/anthropic.",
+	)
 	rootPrefix := fs.String(
 		"rootPrefix",
 		"/",
@@ -240,6 +246,13 @@ func parseAndValidateFlags(args []string) (flags, error) {
 		}
 	}
 
+	// Validate endpoint prefixes if provided.
+	if *endpointPrefixes != "" {
+		if _, err := internalapi.ParseEndpointPrefixes(*endpointPrefixes); err != nil {
+			return flags{}, fmt.Errorf("invalid endpoint prefixes: %w", err)
+		}
+	}
+
 	// Validate extProc extra env vars if provided.
 	if *extProcExtraEnvVars != "" {
 		_, err := controller.ParseExtraEnvVars(*extProcExtraEnvVars)
@@ -270,6 +283,7 @@ func parseAndValidateFlags(args []string) (flags, error) {
 		metricsRequestHeaderAttributes: *metricsRequestHeaderAttributes,
 		metricsRequestHeaderLabels:     *metricsRequestHeaderLabels,
 		spanRequestHeaderAttributes:    *spanRequestHeaderAttributes,
+		endpointPrefixes:               *endpointPrefixes,
 		rootPrefix:                     *rootPrefix,
 		extProcExtraEnvVars:            *extProcExtraEnvVars,
 		extProcImagePullSecrets:        *extProcImagePullSecrets,
@@ -362,6 +376,7 @@ func main() {
 		UDSPath:                        extProcUDSPath,
 		MetricsRequestHeaderAttributes: parsedFlags.metricsRequestHeaderAttributes,
 		TracingRequestHeaderAttributes: parsedFlags.spanRequestHeaderAttributes,
+		EndpointPrefixes:               parsedFlags.endpointPrefixes,
 		RootPrefix:                     parsedFlags.rootPrefix,
 		ExtProcExtraEnvVars:            parsedFlags.extProcExtraEnvVars,
 		ExtProcImagePullSecrets:        parsedFlags.extProcImagePullSecrets,

cmd/controller/main_test.go

@@ -52,6 +52,7 @@ func Test_parseAndValidateFlags(t *testing.T) {
 					tc.dash + "port=:8080",
 					tc.dash + "extProcExtraEnvVars=OTEL_SERVICE_NAME=test;OTEL_TRACES_EXPORTER=console",
 					tc.dash + "spanRequestHeaderAttributes=x-session-id:session.id",
+					tc.dash + "endpointPrefixes=openai:/v1,cohere:/cohere/v2,anthropic:/anthropic/v1",
 					tc.dash + "maxRecvMsgSize=33554432",
 					tc.dash + "watchNamespaces=default,envoy-ai-gateway-system",
 					tc.dash + "cacheSyncTimeout=5m",
@@ -65,6 +66,7 @@ func Test_parseAndValidateFlags(t *testing.T) {
 				require.Equal(t, ":8080", f.extensionServerPort)
 				require.Equal(t, "OTEL_SERVICE_NAME=test;OTEL_TRACES_EXPORTER=console", f.extProcExtraEnvVars)
 				require.Equal(t, "x-session-id:session.id", f.spanRequestHeaderAttributes)
+				require.Equal(t, "openai:/v1,cohere:/cohere/v2,anthropic:/anthropic/v1", f.endpointPrefixes)
 				require.Equal(t, 32*1024*1024, f.maxRecvMsgSize)
 				require.Equal(t, []string{"default", "envoy-ai-gateway-system"}, f.watchNamespaces)
 				require.Equal(t, 5*time.Minute, f.cacheSyncTimeout)
@@ -136,6 +138,16 @@ func Test_parseAndValidateFlags(t *testing.T) {
 				flags:  []string{"--spanRequestHeaderAttributes=:session.id"},
 				expErr: "invalid tracing header attributes",
 			},
+			{
+				name:   "invalid endpointPrefixes - unknown key",
+				flags:  []string{"--endpointPrefixes=foo:/x"},
+				expErr: "invalid endpoint prefixes",
+			},
+			{
+				name:   "invalid endpointPrefixes - missing colon",
+				flags:  []string{"--endpointPrefixes=openai"},
+				expErr: "invalid endpoint prefixes",
+			},
 		} {
 			t.Run(tc.name, func(t *testing.T) {
 				_, err := parseAndValidateFlags(tc.flags)

cmd/extproc/mainlib/main.go

@@ -49,6 +49,8 @@ type extProcFlags struct {
 	rootPrefix string
 	// maxRecvMsgSize is the maximum message size in bytes that the gRPC server can receive.
 	maxRecvMsgSize int
+	// endpointPrefixes is the comma-separated key-value pairs for endpoint prefixes.
+	endpointPrefixes string
 }
 
 // parseAndValidateFlags parses and validates the flags passed to the external processor.
@@ -96,6 +98,11 @@ func parseAndValidateFlags(args []string) (extProcFlags, error) {
 		"/",
 		"The root path prefix for all the processors.",
 	)
+	fs.StringVar(&flags.endpointPrefixes,
+		"endpointPrefixes",
+		"",
+		"Comma-separated key-value pairs for endpoint prefixes. Format: openai:/,cohere:/cohere,anthropic:/anthropic.",
+	)
 	fs.IntVar(&flags.maxRecvMsgSize,
 		"maxRecvMsgSize",
 		4*1024*1024,
@@ -132,6 +139,11 @@ func parseAndValidateFlags(args []string) (extProcFlags, error) {
 			errs = append(errs, fmt.Errorf("failed to parse tracing header mapping: %w", err))
 		}
 	}
+	if flags.endpointPrefixes != "" {
+		if _, err := internalapi.ParseEndpointPrefixes(flags.endpointPrefixes); err != nil {
+			errs = append(errs, fmt.Errorf("failed to parse endpoint prefixes: %w", err))
+		}
+	}
 
 	return flags, errors.Join(errs...)
 }
@@ -217,6 +229,14 @@ func Main(ctx context.Context, args []string, stderr io.Writer) (err error) {
 		return fmt.Errorf("failed to parse tracing header mapping: %w", err)
 	}
 
+	// Parse endpoint prefixes and apply defaults for any missing values.
+	endpointPrefixes, err := internalapi.ParseEndpointPrefixes(flags.endpointPrefixes)
+	if err != nil {
+		return fmt.Errorf("failed to parse endpoint prefixes: %w", err)
+	}
+	// Set defaults for any missing endpoint prefixes.
+	endpointPrefixes.SetDefaults()
+
 	// Create Prometheus registry and reader which automatically converts
 	// attribute to Prometheus-compatible format (e.g. dots to underscores).
 	promRegistry := prometheus.NewRegistry()
@@ -247,13 +267,13 @@ func Main(ctx context.Context, args []string, stderr io.Writer) (err error) {
 	if err != nil {
 		return fmt.Errorf("failed to create external processor server: %w", err)
 	}
-	server.Register(path.Join(flags.rootPrefix, "/v1/chat/completions"), extproc.ChatCompletionProcessorFactory(chatCompletionMetrics))
-	server.Register(path.Join(flags.rootPrefix, "/v1/completions"), extproc.CompletionsProcessorFactory(completionMetrics))
-	server.Register(path.Join(flags.rootPrefix, "/v1/embeddings"), extproc.EmbeddingsProcessorFactory(embeddingsMetrics))
-	server.Register(path.Join(flags.rootPrefix, "/v1/images/generations"), extproc.ImageGenerationProcessorFactory(imageGenerationMetrics))
-	server.Register(path.Join(flags.rootPrefix, "/cohere/v2/rerank"), extproc.RerankProcessorFactory(rerankMetrics))
-	server.Register(path.Join(flags.rootPrefix, "/v1/models"), extproc.NewModelsProcessor)
-	server.Register(path.Join(flags.rootPrefix, "/anthropic/v1/messages"), extproc.MessagesProcessorFactory(messagesMetrics))
+	server.Register(path.Join(flags.rootPrefix, *endpointPrefixes.OpenAI, "/v1/chat/completions"), extproc.ChatCompletionProcessorFactory(chatCompletionMetrics))
+	server.Register(path.Join(flags.rootPrefix, *endpointPrefixes.OpenAI, "/v1/completions"), extproc.CompletionsProcessorFactory(completionMetrics))
+	server.Register(path.Join(flags.rootPrefix, *endpointPrefixes.OpenAI, "/v1/embeddings"), extproc.EmbeddingsProcessorFactory(embeddingsMetrics))
+	server.Register(path.Join(flags.rootPrefix, *endpointPrefixes.OpenAI, "/v1/images/generations"), extproc.ImageGenerationProcessorFactory(imageGenerationMetrics))
+	server.Register(path.Join(flags.rootPrefix, *endpointPrefixes.Cohere, "/v2/rerank"), extproc.RerankProcessorFactory(rerankMetrics))
+	server.Register(path.Join(flags.rootPrefix, *endpointPrefixes.OpenAI, "/v1/models"), extproc.NewModelsProcessor)
+	server.Register(path.Join(flags.rootPrefix, *endpointPrefixes.Anthropic, "/v1/messages"), extproc.MessagesProcessorFactory(messagesMetrics))
 
 	if watchErr := extproc.StartConfigWatcher(ctx, flags.configPath, server, l, time.Second*5); watchErr != nil {
 		return fmt.Errorf("failed to start config watcher: %w", watchErr)

cmd/extproc/mainlib/main_test.go

@@ -82,6 +82,14 @@ func Test_parseAndValidateFlags(t *testing.T) {
 				rootPrefix: "/foo/bar/",
 				logLevel:   slog.LevelDebug,
 			},
+			{
+				name:       "with endpoint prefixes",
+				args:       []string{"-configPath", "/path/to/config.yaml", "-endpointPrefixes", "openai:/,cohere:/cohere,anthropic:/anthropic"},
+				configPath: "/path/to/config.yaml",
+				addr:       ":1063",
+				rootPrefix: "/",
+				logLevel:   slog.LevelInfo,
+			},
 			{
 				name: "with header mapping",
 				args: []string{
@@ -150,6 +158,16 @@ func Test_parseAndValidateFlags(t *testing.T) {
 				args:          []string{"-logLevel", "invalid"},
 				expectedError: "configPath must be provided\nfailed to unmarshal log level: slog: level string \"invalid\": unknown name",
 			},
+			{
+				name:          "invalid endpoint prefixes - unknown key",
+				args:          []string{"-configPath", "/path/to/config.yaml", "-endpointPrefixes", "foo:/x"},
+				expectedError: "failed to parse endpoint prefixes: unknown endpointPrefixes key \"foo\" at position 1 (allowed: openai, cohere, anthropic)",
+			},
+			{
+				name:          "invalid endpoint prefixes - missing colon",
+				args:          []string{"-configPath", "/path/to/config.yaml", "-endpointPrefixes", "openai"},
+				expectedError: "failed to parse endpoint prefixes: invalid endpointPrefixes pair at position 1: \"openai\" (expected format: key:value)",
+			},
 			{
 				name:          "invalid tracing header attributes - missing colon",
 				args:          []string{"-configPath", "/path/to/config.yaml", "-spanRequestHeaderAttributes", "x-session-id"},

internal/controller/controller.go

@@ -87,6 +87,8 @@ type Options struct {
 	ExtProcMaxRecvMsgSize int
 	// MCPSessionEncryptionSeed is the seed used to derive the encryption key for MCP session encryption.
 	MCPSessionEncryptionSeed string
+	// EndpointPrefixes is the comma-separated key-value pairs for endpoint prefixes.
+	EndpointPrefixes string
 }
 
 // StartControllers starts the controllers for the AI Gateway.
@@ -220,6 +222,7 @@ func StartControllers(ctx context.Context, mgr manager.Manager, config *rest.Con
 			options.MetricsRequestHeaderAttributes,
 			options.TracingRequestHeaderAttributes,
 			options.RootPrefix,
+			options.EndpointPrefixes,
 			options.ExtProcExtraEnvVars,
 			options.ExtProcImagePullSecrets,
 			options.ExtProcMaxRecvMsgSize,

internal/controller/gateway_mutator.go

@@ -41,6 +41,7 @@ type gatewayMutator struct {
 	metricsRequestHeaderAttributes string
 	spanRequestHeaderAttributes    string
 	rootPrefix                     string
+	endpointPrefixes               string
 	extProcExtraEnvVars            []corev1.EnvVar
 	extProcImagePullSecrets        []corev1.LocalObjectReference
 	extProcMaxRecvMsgSize          int
@@ -55,7 +56,7 @@ type gatewayMutator struct {
 
 func newGatewayMutator(c client.Client, kube kubernetes.Interface, logger logr.Logger,
 	extProcImage string, extProcImagePullPolicy corev1.PullPolicy, extProcLogLevel,
-	udsPath, metricsRequestHeaderAttributes, spanRequestHeaderAttributes, rootPrefix, extProcExtraEnvVars, extProcImagePullSecrets string, extProcMaxRecvMsgSize int,
+	udsPath, metricsRequestHeaderAttributes, spanRequestHeaderAttributes, rootPrefix, endpointPrefixes, extProcExtraEnvVars, extProcImagePullSecrets string, extProcMaxRecvMsgSize int,
 	extProcAsSideCar bool,
 	mcpSessionEncryptionSeed string,
 ) *gatewayMutator {
@@ -90,6 +91,7 @@ func newGatewayMutator(c client.Client, kube kubernetes.Interface, logger logr.L
 		metricsRequestHeaderAttributes: metricsRequestHeaderAttributes,
 		spanRequestHeaderAttributes:    spanRequestHeaderAttributes,
 		rootPrefix:                     rootPrefix,
+		endpointPrefixes:               endpointPrefixes,
 		extProcExtraEnvVars:            parsedEnvVars,
 		extProcImagePullSecrets:        parsedImagePullSecrets,
 		extProcMaxRecvMsgSize:          extProcMaxRecvMsgSize,
@@ -142,6 +144,11 @@ func (g *gatewayMutator) buildExtProcArgs(filterConfigFullPath string, extProcAd
 		args = append(args, "-spanRequestHeaderAttributes", g.spanRequestHeaderAttributes)
 	}
 
+	// Add endpoint prefixes mapping if configured.
+	if g.endpointPrefixes != "" {
+		args = append(args, "-endpointPrefixes", g.endpointPrefixes)
+	}
+
 	return args
 }
 

internal/controller/gateway_mutator_test.go

@@ -28,7 +28,7 @@ import (
 func TestGatewayMutator_Default(t *testing.T) {
 	fakeClient := requireNewFakeClientWithIndexes(t)
 	fakeKube := fake2.NewClientset()
-	g := newTestGatewayMutator(fakeClient, fakeKube, "", "", "", "", false)
+	g := newTestGatewayMutator(fakeClient, fakeKube, "", "", "", "", "", false)
 	pod := &corev1.Pod{
 		ObjectMeta: metav1.ObjectMeta{Name: "test-pod", Namespace: "test-namespace"},
 		Spec: corev1.PodSpec{
@@ -49,6 +49,7 @@ func TestGatewayMutator_mutatePod(t *testing.T) {
 		name                           string
 		metricsRequestHeaderAttributes string
 		spanRequestHeaderAttributes    string
+		endpointPrefixes               string
 		extProcExtraEnvVars            string
 		extProcImagePullSecrets        string
 		extprocTest                    func(t *testing.T, container corev1.Container)
@@ -83,6 +84,17 @@ func TestGatewayMutator_mutatePod(t *testing.T) {
 				require.True(t, foundMCPSeed)
 			},
 		},
+		{
+			name:             "with endpoint prefixes",
+			endpointPrefixes: "openai:/v1,cohere:/cohere/v2,anthropic:/anthropic/v1",
+			extprocTest: func(t *testing.T, container corev1.Container) {
+				require.Contains(t, container.Args, "-endpointPrefixes")
+				require.Contains(t, container.Args, "openai:/v1,cohere:/cohere/v2,anthropic:/anthropic/v1")
+			},
+			podTest: func(t *testing.T, pod corev1.Pod) {
+				require.Empty(t, pod.Spec.ImagePullSecrets)
+			},
+		},
 		{
 			name:                "with extra env vars",
 			extProcExtraEnvVars: "OTEL_SERVICE_NAME=ai-gateway-extproc;OTEL_TRACES_EXPORTER=otlp",
@@ -191,7 +203,7 @@ func TestGatewayMutator_mutatePod(t *testing.T) {
 				t.Run(fmt.Sprintf("sidecar=%v", sidecar), func(t *testing.T) {
 					fakeClient := requireNewFakeClientWithIndexes(t)
 					fakeKube := fake2.NewClientset()
-					g := newTestGatewayMutator(fakeClient, fakeKube, tt.metricsRequestHeaderAttributes, tt.spanRequestHeaderAttributes, tt.extProcExtraEnvVars, tt.extProcImagePullSecrets, sidecar)
+					g := newTestGatewayMutator(fakeClient, fakeKube, tt.metricsRequestHeaderAttributes, tt.spanRequestHeaderAttributes, tt.endpointPrefixes, tt.extProcExtraEnvVars, tt.extProcImagePullSecrets, sidecar)
 
 					const gwName, gwNamespace = "test-gateway", "test-namespace"
 					err := fakeClient.Create(t.Context(), &aigv1a1.AIGatewayRoute{
@@ -274,11 +286,11 @@ func TestGatewayMutator_mutatePod(t *testing.T) {
 	}
 }
 
-func newTestGatewayMutator(fakeClient client.Client, fakeKube *fake2.Clientset, metricsRequestHeaderAttributes, spanRequestHeaderAttributes, extProcExtraEnvVars, extProcImagePullSecrets string, sidecar bool) *gatewayMutator {
+func newTestGatewayMutator(fakeClient client.Client, fakeKube *fake2.Clientset, metricsRequestHeaderAttributes, spanRequestHeaderAttributes, endpointPrefixes, extProcExtraEnvVars, extProcImagePullSecrets string, sidecar bool) *gatewayMutator {
 	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&zap.Options{Development: true, Level: zapcore.DebugLevel})))
 	return newGatewayMutator(
 		fakeClient, fakeKube, ctrl.Log, "docker.io/envoyproxy/ai-gateway-extproc:latest", corev1.PullIfNotPresent,
-		"info", "/tmp/extproc.sock", metricsRequestHeaderAttributes, spanRequestHeaderAttributes, "/v1", extProcExtraEnvVars, extProcImagePullSecrets, 512*1024*1024,
+		"info", "/tmp/extproc.sock", metricsRequestHeaderAttributes, spanRequestHeaderAttributes, "/v1", endpointPrefixes, extProcExtraEnvVars, extProcImagePullSecrets, 512*1024*1024,
 		sidecar, "seed",
 	)
 }

internal/internalapi/internalapi.go

@@ -125,6 +125,82 @@ func ParseRequestHeaderAttributeMapping(s string) (map[string]string, error) {
 	return result, nil
 }
 
+// EndpointPrefixes represents well-known endpoint prefixes that AI Gateway supports.
+// Only these keys are recognized when parsing the endpointPrefixes flag/value.
+type EndpointPrefixes struct {
+	OpenAI    *string
+	Cohere    *string
+	Anthropic *string
+}
+
+// SetDefaults populates empty fields with default provider prefixes (without version components).
+// Defaults:
+//
+//	openai -> /
+//	cohere -> /cohere
+//	anthropic -> /anthropic
+func (e *EndpointPrefixes) SetDefaults() {
+	if e.OpenAI == nil {
+		prefix := "/"
+		e.OpenAI = &prefix
+	}
+	if e.Cohere == nil {
+		prefix := "/cohere"
+		e.Cohere = &prefix
+	}
+	if e.Anthropic == nil {
+		prefix := "/anthropic"
+		e.Anthropic = &prefix
+	}
+}
+
+// ParseEndpointPrefixes parses a comma-separated list of key:value pairs to populate EndpointPrefixes.
+//
+// Recognized keys (case-sensitive):
+//   - openai
+//   - cohere
+//   - anthropic
+//
+// Format example:
+//
+//	"openai:/,cohere:/cohere,anthropic:/anthropic"
+//
+// Unknown keys cause an error; values must be non-empty.
+func ParseEndpointPrefixes(s string) (EndpointPrefixes, error) {
+	var out EndpointPrefixes
+	if s == "" {
+		return out, nil
+	}
+
+	pairs := strings.Split(s, ",")
+	for i, pair := range pairs {
+		pair = strings.TrimSpace(pair)
+		if pair == "" {
+			return EndpointPrefixes{}, fmt.Errorf("empty endpointPrefixes pair at position %d", i+1)
+		}
+
+		parts := strings.SplitN(pair, ":", 2)
+		if len(parts) != 2 {
+			return EndpointPrefixes{}, fmt.Errorf("invalid endpointPrefixes pair at position %d: %q (expected format: key:value)", i+1, pair)
+		}
+
+		key := strings.TrimSpace(parts[0])
+		value := strings.TrimSpace(parts[1])
+
+		switch key {
+		case "openai":
+			out.OpenAI = &value
+		case "cohere":
+			out.Cohere = &value
+		case "anthropic":
+			out.Anthropic = &value
+		default:
+			return EndpointPrefixes{}, fmt.Errorf("unknown endpointPrefixes key %q at position %d (allowed: openai, cohere, anthropic)", key, i+1)
+		}
+	}
+	return out, nil
+}
+
 // ModelNameHeaderKeyDefault is the default header key for the model name.
 const ModelNameHeaderKeyDefault = aigv1a1.AIModelHeaderKey