Add version-specific reflection API toggle for echo-grpc

Add DISABLE_REFLECTION_V1 and DISABLE_REFLECTION_V1ALPHA environment
variables to allow selective disabling of gRPC reflection API versions.
This enables testing client compatibility with different reflection
protocol versions.

Changes:
- Add DisableReflectionV1 and DisableReflectionV1Alpha config fields
- Update RegisterReflection to support version-specific registration
- Skip reflection registration entirely when both versions are disabled
- Document new environment variables in API reference

Author: lambdalisue

echo-grpc/config.go

@@ -7,19 +7,23 @@ import (
 )
 
 type Config struct {
-	Host                  string
-	Port                  string
-	ReflectionIncludeDeps bool
+	Host                     string
+	Port                     string
+	ReflectionIncludeDeps    bool
+	DisableReflectionV1      bool
+	DisableReflectionV1Alpha bool
 }
 
 func LoadConfig() *Config {
 	// Load .env file if exists (ignore error if not found)
 	_ = godotenv.Load()
 
 	return &Config{
-		Host:                  getEnv("HOST", "0.0.0.0"),
-		Port:                  getEnv("PORT", "50051"),
-		ReflectionIncludeDeps: getEnvBool("REFLECTION_INCLUDE_DEPENDENCIES", false),
+		Host:                     getEnv("HOST", "0.0.0.0"),
+		Port:                     getEnv("PORT", "50051"),
+		ReflectionIncludeDeps:    getEnvBool("REFLECTION_INCLUDE_DEPENDENCIES", false),
+		DisableReflectionV1:      getEnvBool("DISABLE_REFLECTION_V1", false),
+		DisableReflectionV1Alpha: getEnvBool("DISABLE_REFLECTION_V1ALPHA", false),
 	}
 }
 

echo-grpc/docs/api.md

@@ -605,7 +605,7 @@ grpcurl -plaintext -d '{"service": ""}' \
 
 ## Server Reflection
 
-The server supports gRPC server reflection for service discovery.
+The server supports gRPC server reflection for service discovery (both v1 and v1alpha versions).
 
 ```bash
 # List all services
@@ -618,6 +618,14 @@ grpcurl -plaintext localhost:50051 describe echo.v1.Echo
 grpcurl -plaintext localhost:50051 describe echo.v1.EchoRequest
 ```
 
+### Environment Variables
+
+- `REFLECTION_INCLUDE_DEPENDENCIES` (default: `false`) - Include transitive dependencies in reflection responses
+- `DISABLE_REFLECTION_V1` (default: `false`) - Disable gRPC reflection v1 API
+- `DISABLE_REFLECTION_V1ALPHA` (default: `false`) - Disable gRPC reflection v1alpha API
+
+These flags allow testing client compatibility with different reflection API versions.
+
 ## Metadata
 
 Request metadata is echoed back in the `metadata` field of every response. Custom metadata can be sent using grpcurl's `-H` flag:

echo-grpc/main.go

@@ -30,7 +30,7 @@ func main() {
 	healthpb.RegisterHealthServer(s, healthServer)
 
 	// Enable server reflection (v1 and v1alpha)
-	server.RegisterReflection(s, cfg.ReflectionIncludeDeps)
+	server.RegisterReflection(s, cfg.ReflectionIncludeDeps, cfg.DisableReflectionV1, cfg.DisableReflectionV1Alpha)
 
 	log.Printf("Starting server on %s", cfg.Addr())
 	if err := s.Serve(lis); err != nil {