Organize backend into product executable and shared Go modules

backend/product/app/metrics/handler.go

@@ -0,0 +1,40 @@
+package metrics
+
+import (
+	"net/http"
+
+	"git.sendico.io/tech/sxchnge/shared/logging"
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/metrics"
+	"go.uber.org/zap"
+)
+
+type metricsRouter struct {
+	logger  mlogger.Logger
+	handler http.Handler
+}
+
+func (mr *metricsRouter) Finish() {
+	mr.logger.Debug("Stopped")
+}
+
+func (mr *metricsRouter) handle(w http.ResponseWriter, r *http.Request) {
+	mr.logger.Debug("Serving metrics request...")
+	mr.handler.ServeHTTP(w, r)
+}
+
+func newMetricsRouter(logger mlogger.Logger, router chi.Router, endpoint string) *metricsRouter {
+	mr := metricsRouter{
+		logger:  logger.Named("metrics"),
+		handler: metrics.Handler(),
+	}
+
+	logger.Debug("Installing Prometheus middleware...")
+	router.Group(func(r chi.Router) {
+		ep := endpoint + "/metrics"
+		r.Get(ep, mr.handle)
+		logger.Info("Prometheus handler installed", zap.String("endpoint", ep))
+	})
+
+	return &mr
+}