refactor/checkout (#8)

Co-authored-by: matst80 <mats.tornberg@gmail.com>
Reviewed-on: #8
Co-authored-by: Mats Törnberg <mats@tornberg.me>
Co-committed-by: Mats Törnberg <mats@tornberg.me>

cmd/checkout/utils.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"strings"
+
+	"git.k6n.net/go-cart-actor/pkg/cart"
+	"git.k6n.net/go-cart-actor/pkg/checkout"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+)
+
+func getOriginalHost(r *http.Request) string {
+	proxyHost := r.Header.Get("X-Forwarded-Host")
+	if proxyHost != "" {
+		return proxyHost
+	}
+	return r.Host
+}
+
+func getClientIp(r *http.Request) string {
+	ip := r.Header.Get("X-Forwarded-For")
+	if ip == "" {
+		ip = r.RemoteAddr
+	}
+	return ip
+}
+
+func getCurrency(country string) string {
+	if country == "no" {
+		return "NOK"
+	}
+	return "SEK"
+}
+
+func getLocale(country string) string {
+	if country == "no" {
+		return "nb-no"
+	}
+	return "sv-se"
+}
+
+func getCountryFromHost(host string) string {
+	if strings.Contains(strings.ToLower(host), "-no") {
+		return "no"
+	}
+	if strings.Contains(strings.ToLower(host), "-se") {
+		return "se"
+	}
+	return ""
+}
+
+func (a *CheckoutPoolServer) reserveInventory(ctx context.Context, grain *checkout.CheckoutGrain) error {
+	if a.inventoryService != nil {
+		inventoryRequests := getInventoryRequests(grain.CartState.Items)
+		_, err := a.inventoryService.ReservationCheck(ctx, inventoryRequests...)
+		if err != nil {
+			logger.WarnContext(ctx, "placeorder inventory check failed")
+			return err
+		}
+	}
+	return nil
+}
+
+func CheckoutIdHandler(fn func(w http.ResponseWriter, r *http.Request, checkoutId checkout.CheckoutId) error) func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		var id checkout.CheckoutId
+		raw := r.PathValue("id")
+		if raw == "" {
+			id = checkout.CheckoutId(cart.MustNewCartId())
+			w.Header().Set("Set-Checkout-Id", id.String())
+		} else {
+			if parsedId, ok := cart.ParseCartId(raw); !ok {
+				w.WriteHeader(http.StatusBadRequest)
+				w.Write([]byte("checkout id is invalid"))
+				return
+			} else {
+				id = checkout.CheckoutId(parsedId)
+			}
+		}
+
+		err := fn(w, r, id)
+		if err != nil {
+			log.Printf("Server error, not remote error: %v\n", err)
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(err.Error()))
+		}
+	}
+}
+
+func (s *CheckoutPoolServer) ProxyHandler(fn func(w http.ResponseWriter, r *http.Request, checkoutId checkout.CheckoutId) error) func(w http.ResponseWriter, r *http.Request, checkoutId checkout.CheckoutId) error {
+	return func(w http.ResponseWriter, r *http.Request, checkoutId checkout.CheckoutId) error {
+		if ownerHost, ok := s.OwnerHost(uint64(checkoutId)); ok {
+			ctx, span := tracer.Start(r.Context(), "proxy")
+			defer span.End()
+			span.SetAttributes(attribute.String("checkoutid", checkoutId.String()))
+			hostAttr := attribute.String("other host", ownerHost.Name())
+			span.SetAttributes(hostAttr)
+			logger.InfoContext(ctx, "checkout proxyed", "result", ownerHost.Name())
+			proxyCalls.Add(ctx, 1, metric.WithAttributes(hostAttr))
+			handled, err := ownerHost.Proxy(uint64(checkoutId), w, r, nil)
+
+			grainLookups.Inc()
+			if err == nil && handled {
+				return nil
+			}
+		}
+		_, span := tracer.Start(r.Context(), "own")
+		span.SetAttributes(attribute.String("checkoutid", checkoutId.String()))
+		defer span.End()
+		return fn(w, r, checkoutId)
+	}
+}