initial commit

apps/node-agent/internal/health/health.go

@@ -0,0 +1,78 @@
+package health
+
+import (
+	"encoding/json"
+	"net/http"
+	"sync/atomic"
+	"time"
+)
+
+// Status represents agent health for liveness and readiness probes.
+type Status struct {
+	Status    string    `json:"status"`
+	Agent     string    `json:"agent"`
+	Version   string    `json:"version"`
+	Uptime    string    `json:"uptime"`
+	Timestamp time.Time `json:"timestamp"`
+}
+
+// Server exposes HTTP health endpoints for the node agent.
+type Server struct {
+	addr      string
+	version   string
+	startedAt time.Time
+	ready     atomic.Bool
+	mux       *http.ServeMux
+}
+
+// NewServer creates a health HTTP server bound to addr.
+func NewServer(addr, version string) *Server {
+	s := &Server{
+		addr:      addr,
+		version:   version,
+		startedAt: time.Now().UTC(),
+		mux:       http.NewServeMux(),
+	}
+	s.mux.HandleFunc("GET /healthz", s.handleLiveness)
+	s.mux.HandleFunc("GET /readyz", s.handleReadiness)
+	return s
+}
+
+// SetReady toggles readiness for orchestration probes.
+func (s *Server) SetReady(ready bool) {
+	s.ready.Store(ready)
+}
+
+// Handler returns the HTTP handler for embedding in tests.
+func (s *Server) Handler() http.Handler {
+	return s.mux
+}
+
+// ListenAndServe starts the health server.
+func (s *Server) ListenAndServe() error {
+	return http.ListenAndServe(s.addr, s.mux)
+}
+
+func (s *Server) handleLiveness(w http.ResponseWriter, _ *http.Request) {
+	s.writeStatus(w, http.StatusOK, "alive")
+}
+
+func (s *Server) handleReadiness(w http.ResponseWriter, _ *http.Request) {
+	if !s.ready.Load() {
+		s.writeStatus(w, http.StatusServiceUnavailable, "not_ready")
+		return
+	}
+	s.writeStatus(w, http.StatusOK, "ready")
+}
+
+func (s *Server) writeStatus(w http.ResponseWriter, code int, status string) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(code)
+	_ = json.NewEncoder(w).Encode(Status{
+		Status:    status,
+		Agent:     "node-agent",
+		Version:   s.version,
+		Uptime:    time.Since(s.startedAt).Round(time.Second).String(),
+		Timestamp: time.Now().UTC(),
+	})
+}