fix(consul): Fix health checks for gRPC services in Docker

- Add gRPC health check support to Consul registry
  - Services are gRPC-only, not HTTP
  - Consul was trying HTTP health checks which failed
  - Now uses gRPC health checks via grpc.health.v1.Health service

- Update HealthCheckConfig to support both HTTP and gRPC
  - Add GRPC field for gRPC service name
  - Add UseGRPC flag to choose health check type
  - Default to gRPC for services (use_grpc: true in config)

- Fix service address registration in Docker
  - Services now register with Docker service name (e.g., auth-service)
  - Allows Consul to reach services via Docker network DNS
  - Falls back to localhost for local development

- Update default.yaml to enable gRPC health checks
  - Set use_grpc: true
  - Set grpc: grpc.health.v1.Health

This fixes services being deregistered from Consul due to failed
HTTP health checks. Services will now pass gRPC health checks.

cmd/audit-service/main.go

@@ -183,8 +183,14 @@ func registerLifecycle(
 			serviceID := fmt.Sprintf("audit-service-%d", time.Now().Unix())
 			host := cfg.GetString("services.audit.host")
 			if host == "" {
+				// In Docker, use service name for Consul to reach the service
+				// For local development, use localhost
+				if os.Getenv("ENVIRONMENT") == "production" || os.Getenv("DOCKER") == "true" {
+					host = "audit-service" // Docker service name
+				} else {
 					host = "localhost"
 				}
+			}
 			port := grpcServer.Port()
 
 			instance := &registry.ServiceInstance{

cmd/auth-service/main.go

@@ -190,8 +190,14 @@ func registerLifecycle(
 			serviceID := fmt.Sprintf("auth-service-%d", time.Now().Unix())
 			host := cfg.GetString("services.auth.host")
 			if host == "" {
+				// In Docker, use service name for Consul to reach the service
+				// For local development, use localhost
+				if os.Getenv("ENVIRONMENT") == "production" || os.Getenv("DOCKER") == "true" {
+					host = "auth-service" // Docker service name
+				} else {
 					host = "localhost"
 				}
+			}
 			port := grpcServer.Port()
 
 			instance := &registry.ServiceInstance{

cmd/authz-service/main.go

@@ -183,8 +183,14 @@ func registerLifecycle(
 			serviceID := fmt.Sprintf("authz-service-%d", time.Now().Unix())
 			host := cfg.GetString("services.authz.host")
 			if host == "" {
+				// In Docker, use service name for Consul to reach the service
+				// For local development, use localhost
+				if os.Getenv("ENVIRONMENT") == "production" || os.Getenv("DOCKER") == "true" {
+					host = "authz-service" // Docker service name
+				} else {
 					host = "localhost"
 				}
+			}
 			port := grpcServer.Port()
 
 			instance := &registry.ServiceInstance{

cmd/identity-service/main.go

@@ -183,8 +183,14 @@ func registerLifecycle(
 			serviceID := fmt.Sprintf("identity-service-%d", time.Now().Unix())
 			host := cfg.GetString("services.identity.host")
 			if host == "" {
+				// In Docker, use service name for Consul to reach the service
+				// For local development, use localhost
+				if os.Getenv("ENVIRONMENT") == "production" || os.Getenv("DOCKER") == "true" {
+					host = "identity-service" // Docker service name
+				} else {
 					host = "localhost"
 				}
+			}
 			port := grpcServer.Port()
 
 			instance := &registry.ServiceInstance{

config/default.yaml

@@ -36,6 +36,8 @@ registry:
       timeout: "3s"
       deregister_after: "30s"
       http: "/healthz"
+      grpc: "grpc.health.v1.Health"
+      use_grpc: true
 
 services:
   audit:

internal/di/providers.go

@@ -218,8 +218,14 @@ func ProvideServiceRegistry() fx.Option {
 				healthCheckDeregisterAfter = 30 * time.Second
 			}
 			healthCheckHTTP := cfg.GetString("registry.consul.health_check.http")
-			if healthCheckHTTP == "" {
+			healthCheckGRPC := cfg.GetString("registry.consul.health_check.grpc")
-				healthCheckHTTP = "/healthz"
+			useGRPC := cfg.GetBool("registry.consul.health_check.use_grpc")
+			// Default to gRPC if not explicitly set (services are gRPC by default)
+			if !cfg.IsSet("registry.consul.health_check.use_grpc") {
+				useGRPC = true
+			}
+			if healthCheckGRPC == "" {
+				healthCheckGRPC = "grpc.health.v1.Health"
 			}
 
 			consulCfg.HealthCheck = consul.HealthCheckConfig{
@@ -227,6 +233,8 @@ func ProvideServiceRegistry() fx.Option {
 				Timeout:         healthCheckTimeout,
 				DeregisterAfter: healthCheckDeregisterAfter,
 				HTTP:            healthCheckHTTP,
+				GRPC:            healthCheckGRPC,
+				UseGRPC:         useGRPC,
 			}
 
 			return consul.NewRegistry(consulCfg)

internal/registry/consul/consul.go

@@ -29,7 +29,9 @@ type HealthCheckConfig struct {
 	Interval        time.Duration // Health check interval
 	Timeout         time.Duration // Health check timeout
 	DeregisterAfter time.Duration // Time to wait before deregistering unhealthy service
-	HTTP            string        // HTTP health check endpoint (e.g., "/healthz")
+	HTTP            string        // HTTP health check endpoint (e.g., "/healthz") - for HTTP services
+	GRPC            string        // gRPC health check service name (e.g., "grpc.health.v1.Health") - for gRPC services
+	UseGRPC         bool          // Whether to use gRPC health checks instead of HTTP
 }
 
 // NewRegistry creates a new Consul-based service registry.
@@ -68,7 +70,21 @@ func (r *ConsulRegistry) Register(ctx context.Context, service *registry.Service
 	}
 
 	// Add health check if configured
-	if r.config.HealthCheck.HTTP != "" {
+	if r.config.HealthCheck.UseGRPC {
+		// Use gRPC health check for gRPC services
+		// Format: host:port/service or host:port (uses default health service)
+		grpcAddr := fmt.Sprintf("%s:%d", service.Address, service.Port)
+		if r.config.HealthCheck.GRPC != "" {
+			grpcAddr = fmt.Sprintf("%s:%d/%s", service.Address, service.Port, r.config.HealthCheck.GRPC)
+		}
+		registration.Check = &consulapi.AgentServiceCheck{
+			GRPC:                           grpcAddr,
+			Interval:                       r.config.HealthCheck.Interval.String(),
+			Timeout:                        r.config.HealthCheck.Timeout.String(),
+			DeregisterCriticalServiceAfter: r.config.HealthCheck.DeregisterAfter.String(),
+		}
+	} else if r.config.HealthCheck.HTTP != "" {
+		// Use HTTP health check for HTTP services
 		healthCheckURL := fmt.Sprintf("http://%s:%d%s", service.Address, service.Port, r.config.HealthCheck.HTTP)
 		registration.Check = &consulapi.AgentServiceCheck{
 			HTTP:                           healthCheckURL,