Support expose health check endpoint /health for cloud deployment

Author: anhthii

cmd/mpcium/main.go

@@ -15,6 +15,7 @@ import (
 	"github.com/fystack/mpcium/pkg/constant"
 	"github.com/fystack/mpcium/pkg/event"
 	"github.com/fystack/mpcium/pkg/eventconsumer"
+	"github.com/fystack/mpcium/pkg/healthcheck"
 	"github.com/fystack/mpcium/pkg/identity"
 	"github.com/fystack/mpcium/pkg/infra"
 	"github.com/fystack/mpcium/pkg/keyinfo"
@@ -241,6 +242,21 @@ func runNode(ctx context.Context, c *cli.Command) error {
 	}
 	logger.Info("[READY] Node is ready", "nodeID", nodeID)
 
+	// Start health check server (disabled by default)
+	var healthServer *healthcheck.Server
+	if viper.GetBool("healthcheck.enabled") {
+		healthAddr := viper.GetString("healthcheck.address")
+		if healthAddr == "" {
+			healthAddr = ":8080"
+		}
+		healthServer = healthcheck.NewServer(healthAddr, peerRegistry, natsConn, consulClient)
+		go func() {
+			if err := healthServer.Start(); err != nil {
+				logger.Error("Health check server error", err)
+			}
+		}()
+	}
+
 	logger.Info("Starting consumers", "nodeID", nodeID)
 	appContext, cancel := context.WithCancel(context.Background())
 	//Setup signal handling to cancel context on termination signals.
@@ -251,6 +267,15 @@ func runNode(ctx context.Context, c *cli.Command) error {
 		logger.Warn("Shutdown signal received, canceling context...")
 		cancel()
 
+		// Shutdown health check server if it was started
+		if healthServer != nil {
+			shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 5*time.Second)
+			defer shutdownCancel()
+			if err := healthServer.Shutdown(shutdownCtx); err != nil {
+				logger.Error("Failed to shutdown health check server", err)
+			}
+		}
+
 		// Resign from peer registry first (before closing NATS)
 		if err := peerRegistry.Resign(); err != nil {
 			logger.Error("Failed to resign from peer registry", err)

config.prod.yaml.template

@@ -23,3 +23,7 @@ backup_dir: backups
 max_concurrent_keygen: 2
 max_concurrent_signing: 10
 session_warm_up_delay_ms: 100
+
+healthcheck:
+  enabled: false  # disabled by default, set to true for cloud deployment
+  address: "127.0.0.1:8080"

config.yaml.template

@@ -15,6 +15,10 @@ backup_dir: backups
 max_concurrent_keygen: 2
 max_concurrent_signing: 10
 session_warm_up_delay_ms: 100
+healthcheck:
+  enabled: true  # disabled by default, set to true for cloud deployment
+  address: "0.0.0.0:8080"
+
 
 # Authorization (optional)
 # authorization:

pkg/healthcheck/server.go

@@ -0,0 +1,148 @@
+package healthcheck
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net"
+	"net/http"
+	"time"
+
+	"github.com/fystack/mpcium/pkg/logger"
+	"github.com/fystack/mpcium/pkg/mpc"
+	"github.com/hashicorp/consul/api"
+	"github.com/nats-io/nats.go"
+)
+
+// Server provides HTTP health check endpoints for Kubernetes probes
+type Server struct {
+	httpServer   *http.Server
+	peerRegistry mpc.PeerRegistry
+	natsConn     *nats.Conn
+	consulClient *api.Client
+}
+
+// HealthResponse represents the JSON response for health check endpoints
+type HealthResponse struct {
+	Status    string         `json:"status"`
+	Live      bool           `json:"live"`
+	Ready     bool           `json:"ready"`
+	Details   map[string]any `json:"details,omitempty"`
+}
+
+// NewServer creates a new health check HTTP server
+func NewServer(addr string, peerRegistry mpc.PeerRegistry, natsConn *nats.Conn, consulClient *api.Client) *Server {
+	s := &Server{
+		peerRegistry: peerRegistry,
+		natsConn:     natsConn,
+		consulClient: consulClient,
+	}
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/health", s.healthHandler)
+
+	s.httpServer = &http.Server{
+		Addr:         addr,
+		Handler:      mux,
+		ReadTimeout:  5 * time.Second,
+		WriteTimeout: 5 * time.Second,
+		IdleTimeout:  15 * time.Second,
+	}
+
+	return s
+}
+
+// Start begins serving health check endpoints
+func (s *Server) Start() error {
+	addr := s.httpServer.Addr
+
+	// Parse host and port from address
+	host, port, err := net.SplitHostPort(addr)
+	if err != nil {
+		// If parsing fails, just use the address as-is
+		logger.Info("Starting health check server", "address", addr)
+	} else {
+		// Replace empty host or 0.0.0.0 with localhost for display
+		if host == "" || host == "0.0.0.0" {
+			host = "localhost"
+		}
+		endpoint := fmt.Sprintf("http://%s:%s/health", host, port)
+		logger.Info("Starting health check server", "endpoint", endpoint)
+	}
+
+	if err := s.httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+		return fmt.Errorf("health check server failed: %w", err)
+	}
+	return nil
+}
+
+// Shutdown gracefully stops the health check server
+func (s *Server) Shutdown(ctx context.Context) error {
+	logger.Info("Shutting down health check server")
+	return s.httpServer.Shutdown(ctx)
+}
+
+// healthHandler responds to health check requests
+// This endpoint checks both liveness and readiness in a single response
+func (s *Server) healthHandler(w http.ResponseWriter, r *http.Request) {
+	details := make(map[string]any)
+	ready := true
+	live := true // Service is always live if it can respond
+
+	// Check NATS connection
+	natsConnected := s.natsConn != nil && s.natsConn.IsConnected()
+	details["nats_connected"] = natsConnected
+	if !natsConnected {
+		ready = false
+	}
+
+	// Check Consul connection
+	consulConnected := false
+	if s.consulClient != nil {
+		if leader, err := s.consulClient.Status().Leader(); err == nil && leader != "" {
+			consulConnected = true
+		}
+	}
+	details["consul_connected"] = consulConnected
+	if !consulConnected {
+		ready = false
+	}
+
+	// Check peer registry readiness (includes ECDH completion)
+	if s.peerRegistry != nil {
+		peersReady := s.peerRegistry.ArePeersReady()
+		majorityReady := s.peerRegistry.AreMajorityReady()
+		readyCount := s.peerRegistry.GetReadyPeersCount()
+		totalCount := s.peerRegistry.GetTotalPeersCount()
+
+		details["peers_ready_count"] = fmt.Sprintf("%d/%d", readyCount, totalCount)
+		details["all_peers_ready"] = peersReady
+		details["majority_ready"] = majorityReady
+
+		// Node is ready if majority of peers are ready (allows for some fault tolerance)
+		if !majorityReady {
+			ready = false
+		}
+	} else {
+		details["peers_available"] = false
+		ready = false
+	}
+
+	response := HealthResponse{
+		Live:    live,
+		Ready:   ready,
+		Details: details,
+	}
+
+	if ready {
+		response.Status = "ready"
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+	} else {
+		response.Status = "not_ready"
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusServiceUnavailable)
+	}
+
+	json.NewEncoder(w).Encode(response)
+}