feat: add kafka and db health status

internal/app/server/events.go

@@ -13,15 +13,21 @@ import (
 )
 
 // RunEventLoop runs the server event loop until ctx is cancelled.
-// Handles: location events -> LocationToBeaconService, alert events -> update tracker in DB, ticker -> publish trackers to mqtt.
+// Handles: location events -> LocationToBeaconService, alert events -> update tracker in DB, ticker -> publish trackers to mqtt, health ticker -> Kafka and DB status.
 func RunEventLoop(ctx context.Context, a *ServerApp) {
 	beaconTicker := time.NewTicker(config.MEDIUM_TICKER_INTERVAL)
 	defer beaconTicker.Stop()
+	healthCheckTicker := time.NewTicker(config.LARGE_TICKER_INTERVAL)
+	defer healthCheckTicker.Stop()
 
 	for {
 		select {
 		case <-ctx.Done():
 			return
+		case <-healthCheckTicker.C:
+			kafkaSt := CheckKafkaHealth(ctx, a.Cfg.KafkaURL)
+			dbSt := CheckDBHealth(ctx, a.DB)
+			a.AppState.UpdateServerHealth(kafkaSt, dbSt)
 		case msg := <-a.ChHealthLocation:
 			a.AppState.UpdateLocationHealth(msg)
 		case msg := <-a.ChHealthDecoder:

internal/app/server/healthcheck.go

@@ -0,0 +1,44 @@
+package server
+
+import (
+	"context"
+	"strings"
+	"time"
+
+	"github.com/AFASystems/presence/internal/pkg/common/appcontext"
+	"github.com/segmentio/kafka-go"
+	"gorm.io/gorm"
+)
+
+const healthCheckTimeout = 3 * time.Second
+
+// CheckKafkaHealth dials the broker and returns ServiceStatus. Uses first broker from kafkaURL (comma-separated).
+func CheckKafkaHealth(ctx context.Context, kafkaURL string) appcontext.ServiceStatus {
+	if kafkaURL == "" {
+		return appcontext.ServiceStatus{Status: "down", Message: "no broker URL"}
+	}
+	broker := strings.TrimSpace(strings.Split(kafkaURL, ",")[0])
+	tctx, cancel := context.WithTimeout(ctx, healthCheckTimeout)
+	defer cancel()
+	dialer := &kafka.Dialer{Timeout: healthCheckTimeout}
+	conn, err := dialer.DialContext(tctx, "tcp", broker)
+	if err != nil {
+		return appcontext.ServiceStatus{Status: "down", Message: err.Error()}
+	}
+	_ = conn.Close()
+	return appcontext.ServiceStatus{Status: "up"}
+}
+
+// CheckDBHealth pings the database and returns ServiceStatus.
+func CheckDBHealth(ctx context.Context, db *gorm.DB) appcontext.ServiceStatus {
+	sqlDB, err := db.DB()
+	if err != nil {
+		return appcontext.ServiceStatus{Status: "down", Message: err.Error()}
+	}
+	tctx, cancel := context.WithTimeout(ctx, healthCheckTimeout)
+	defer cancel()
+	if err := sqlDB.PingContext(tctx); err != nil {
+		return appcontext.ServiceStatus{Status: "down", Message: err.Error()}
+	}
+	return appcontext.ServiceStatus{Status: "up"}
+}

internal/pkg/common/appcontext/context.go

@@ -78,6 +78,8 @@ func NewAppState() *AppState {
 					ActiveBeacons: []string{},
 				},
 			},
+			Kafka:    ServiceStatus{Status: "unknown"},
+			Database: ServiceStatus{Status: "unknown"},
 		},
 	}
 }
@@ -106,6 +108,14 @@ func (m *AppState) UpdateBridgeHealth(h BridgeHealth) {
 	m.mu.Unlock()
 }
 
+// UpdateServerHealth updates Kafka and database status (called by server after checking broker and DB).
+func (m *AppState) UpdateServerHealth(kafka, database ServiceStatus) {
+	m.mu.Lock()
+	m.health.Kafka = kafka
+	m.health.Database = database
+	m.mu.Unlock()
+}
+
 func (m *AppState) GetLocationHealth(k *kafkaclient.KafkaManager) ([]byte, error) {
 	m.health.Location.GetUptime(m.startTime)
 	m.health.Location.GetActiveReaders(k)

internal/pkg/common/appcontext/health.go

@@ -7,6 +7,12 @@ import (
 	"github.com/AFASystems/presence/internal/pkg/kafkaclient"
 )
 
+// ServiceStatus represents the health of an external service (e.g. Kafka, database).
+type ServiceStatus struct {
+	Status  string `json:"status"`  // "up", "down", "unknown"
+	Message string `json:"message,omitempty"`
+}
+
 type BaseHealth struct {
 	Uptime        time.Duration `json:"uptime"`
 	ActiveReaders []string      `json:"activeReaders" gorm:"type:jsonb"`
@@ -29,9 +35,11 @@ type BridgeHealth struct {
 }
 
 type Health struct {
-	Location LocationHealth `gorm:"embedded;embeddedPrefix:loc_"`
-	Decoder  DecoderHealth  `gorm:"embedded;embeddedPrefix:dec_"`
-	Bridge   BridgeHealth   `gorm:"embedded;embeddedPrefix:brg_"`
+	Location LocationHealth `json:"location" gorm:"embedded;embeddedPrefix:loc_"`
+	Decoder  DecoderHealth  `json:"decoder" gorm:"embedded;embeddedPrefix:dec_"`
+	Bridge   BridgeHealth   `json:"bridge" gorm:"embedded;embeddedPrefix:brg_"`
+	Kafka    ServiceStatus  `json:"kafka"`
+	Database ServiceStatus  `json:"database"`
 }
 
 func (b *BaseHealth) GetUptime(startTime time.Time) {