initial commit

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

@@ -0,0 +1,92 @@
+package agent
+
+import (
+	"context"
+	"log/slog"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/hexahost/gamecloud/node-agent/internal/config"
+	"github.com/hexahost/gamecloud/node-agent/internal/health"
+)
+
+const Version = "0.1.0-phase0"
+
+// Agent coordinates the node agent lifecycle until shutdown.
+type Agent struct {
+	cfg    *config.Config
+	log    *slog.Logger
+	health *health.Server
+}
+
+// New creates an agent instance from configuration.
+func New(cfg *config.Config, log *slog.Logger) *Agent {
+	return &Agent{
+		cfg:    cfg,
+		log:    log,
+		health: health.NewServer(cfg.HealthListenAddr, Version),
+	}
+}
+
+// Run starts the agent loop and blocks until context cancellation or signal.
+func (a *Agent) Run(ctx context.Context) error {
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	sigCh := make(chan os.Signal, 1)
+	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+	defer signal.Stop(sigCh)
+
+	errCh := make(chan error, 1)
+	go func() {
+		a.log.Info("health server listening", "addr", a.cfg.HealthListenAddr)
+		if err := a.health.ListenAndServe(); err != nil {
+			errCh <- err
+		}
+	}()
+
+	a.health.SetReady(true)
+	a.log.Info("agent started",
+		"node_id", a.cfg.NodeID,
+		"control_plane", a.cfg.ControlPlaneURL,
+		"version", Version,
+	)
+
+	ticker := time.NewTicker(a.cfg.HeartbeatInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return a.shutdown(ctx.Err())
+		case sig := <-sigCh:
+			a.log.Info("shutdown signal received", "signal", sig.String())
+			return a.shutdown(nil)
+		case err := <-errCh:
+			return err
+		case <-ticker.C:
+			a.log.Debug("heartbeat tick",
+				"node_id", a.cfg.NodeID,
+				"interval", a.cfg.HeartbeatInterval.String(),
+			)
+		}
+	}
+}
+
+func (a *Agent) shutdown(reason error) error {
+	a.health.SetReady(false)
+	a.log.Info("agent shutting down", "grace", a.cfg.ShutdownGracePeriod.String())
+
+	timer := time.NewTimer(a.cfg.ShutdownGracePeriod)
+	defer timer.Stop()
+	<-timer.C
+
+	if reason != nil && reason != context.Canceled {
+		a.log.Warn("shutdown with error", "error", reason)
+		return reason
+	}
+	a.log.Info("agent stopped")
+	return nil
+}