Health server runs on 127.0.0.1:9999, fix #272

internal/healthcheck/server.go

@@ -0,0 +1,54 @@
+package healthcheck
+
+import (
+	"context"
+	"errors"
+	"net"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/qdm12/golibs/logging"
+)
+
+type Server interface {
+	Run(ctx context.Context, wg *sync.WaitGroup)
+}
+
+type server struct {
+	address string
+	logger  logging.Logger
+	handler http.Handler
+}
+
+func NewServer(address string, logger logging.Logger) Server {
+	return &server{
+		address: address,
+		logger:  logger.WithPrefix("healthcheck: "),
+		handler: newHandler(logger, &net.Resolver{}),
+	}
+}
+
+func (s *server) Run(ctx context.Context, wg *sync.WaitGroup) {
+	server := http.Server{
+		Addr:    s.address,
+		Handler: s.handler,
+	}
+	go func() {
+		defer wg.Done()
+		<-ctx.Done()
+		s.logger.Warn("context canceled: shutting down server")
+		defer s.logger.Warn("server shut down")
+		const shutdownGraceDuration = 2 * time.Second
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), shutdownGraceDuration)
+		defer cancel()
+		if err := server.Shutdown(shutdownCtx); err != nil {
+			s.logger.Error("failed shutting down: %s", err)
+		}
+	}()
+	s.logger.Info("listening on %s", s.address)
+	err := server.ListenAndServe()
+	if err != nil && !errors.Is(ctx.Err(), context.Canceled) {
+		s.logger.Error(err)
+	}
+}