Chapter 30: Server Reflection and Health Checking

Server Reflection

Allows clients to discover available services and methods at runtime (like Swagger for REST):

// Enable reflection in C++ server:
#include <grpcpp/ext/proto_server_reflection_plugin.h>
grpc::reflection::InitProtoReflectionServerBuilderPlugin();

// Now grpcurl can discover services without .proto files:
$ grpcurl -plaintext localhost:50051 list
$ grpcurl -plaintext localhost:50051 describe mypackage.MyService

Health Checking Protocol

// Standard health check service (grpc.health.v1.Health):
service Health {
  rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
  rpc Watch(HealthCheckRequest) returns (stream HealthCheckResponse);
}

// Response status: UNKNOWN, SERVING, NOT_SERVING
// Used by: Kubernetes liveness/readiness probes, load balancers

Kubernetes Integration

# Pod spec with gRPC health check:
livenessProbe:
  grpc:
    port: 50051
  initialDelaySeconds: 5
readinessProbe:
  grpc:
    port: 50051
← PreviousNext →