frontend: integrate recommmendationservice

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>

src/frontend/handlers.go

@@ -95,7 +95,7 @@ func (fe *frontendServer) productHandler(w http.ResponseWriter, r *http.Request)
 		http.Error(w, "product id not specified", http.StatusBadRequest)
 		return
 	}
-	log.Printf("[productHandler] id=%s currency=%s", id, currentCurrency(r))
+	log.Printf("[productHandler] id=%s currency=%s session=%s", id, currentCurrency(r), sessionID(r))
 	p, err := fe.getProduct(r.Context(), id)
 	if err != nil {
 		http.Error(w, fmt.Sprintf("could not retrieve product: %+v", err), http.StatusInternalServerError)
@@ -106,6 +106,7 @@ func (fe *frontendServer) productHandler(w http.ResponseWriter, r *http.Request)
 		http.Error(w, fmt.Sprintf("could not retrieve currencies: %+v", err), http.StatusInternalServerError)
 		return
 	}
+
 	cart, err := fe.getCart(r.Context(), sessionID(r))
 	if err != nil {
 		http.Error(w, fmt.Sprintf("could not retrieve cart: %+v", err), http.StatusInternalServerError)
@@ -120,6 +121,13 @@ func (fe *frontendServer) productHandler(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
+	recommendations, err := fe.getRecommendations(r.Context(), sessionID(r), []string{id})
+	if err != nil {
+		http.Error(w, fmt.Sprintf("failed to get product recommendations: %+v", err), http.StatusInternalServerError)
+		return
+	}
+	log.Printf("cart size=%d", len(cart))
+
 	product := struct {
 		Item  *pb.Product
 		Price *pb.Money
@@ -130,6 +138,7 @@ func (fe *frontendServer) productHandler(w http.ResponseWriter, r *http.Request)
 		"currencies":      currencies,
 		"product":         product,
 		"session_id":      sessionID(r),
+		"recommendations": recommendations,
 		"cart_size":       len(cart),
 	}); err != nil {
 		log.Println(err)
@@ -183,6 +192,12 @@ func (fe *frontendServer) viewCartHandler(w http.ResponseWriter, r *http.Request
 		return
 	}
 
+	recommendations, err := fe.getRecommendations(r.Context(), sessionID(r), cartIDs(cart))
+	if err != nil {
+		http.Error(w, fmt.Sprintf("failed to get product recommendations: %+v", err), http.StatusInternalServerError)
+		return
+	}
+
 	type cartItemView struct {
 		Item     *pb.Product
 		Quantity int32
@@ -214,6 +229,7 @@ func (fe *frontendServer) viewCartHandler(w http.ResponseWriter, r *http.Request
 		"user_currency":   currentCurrency(r),
 		"currencies":      currencies,
 		"session_id":      sessionID(r),
+		"recommendations": recommendations,
 		"cart_size":       len(cart),
 		"items":           items,
 	}); err != nil {
@@ -265,3 +281,11 @@ func sessionID(r *http.Request) string {
 	}
 	return ""
 }
+
+func cartIDs(c []*pb.CartItem) []string {
+	out := make([]string, len(c))
+	for i, v := range c {
+		out[i] = v.GetProductId()
+	}
+	return out
+}

src/frontend/main.go

@@ -37,6 +37,9 @@ type frontendServer struct {
 
 	cartSvcAddr string
 	cartSvcConn *grpc.ClientConn
+
+	recommendationSvcAddr string
+	recommendationSvcConn *grpc.ClientConn
 }
 
 func main() {
@@ -51,6 +54,7 @@ func main() {
 	mustMapEnv(&svc.productCatalogSvcAddr, "PRODUCT_CATALOG_SERVICE_ADDR")
 	mustMapEnv(&svc.currencySvcAddr, "CURRENCY_SERVICE_ADDR")
 	mustMapEnv(&svc.cartSvcAddr, "CART_SERVICE_ADDR")
+	mustMapEnv(&svc.recommendationSvcAddr, "RECOMMENDATION_SERVICE_ADDR")
 
 	var err error
 	svc.currencySvcConn, err = grpc.DialContext(ctx, svc.currencySvcAddr, grpc.WithInsecure())
@@ -65,6 +69,10 @@ func main() {
 	if err != nil {
 		log.Fatalf("failed to connect cart service at %s: %+v", svc.cartSvcAddr, err)
 	}
+	svc.recommendationSvcConn, err = grpc.DialContext(ctx, svc.recommendationSvcAddr, grpc.WithInsecure())
+	if err != nil {
+		log.Fatalf("failed to connect recommendation service at %s: %+v", svc.recommendationSvcConn, err)
+	}
 
 	r := mux.NewRouter()
 	r.HandleFunc("/", ensureSessionID(svc.homeHandler)).Methods(http.MethodGet, http.MethodHead)

src/frontend/rpc.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"fmt"
 
 	"google.golang.org/grpc/codes"
 
@@ -74,3 +75,23 @@ func (fe *frontendServer) convertCurrency(ctx context.Context, money *pb.Money,
 			From:   money,
 			ToCode: currency})
 }
+
+func (fe *frontendServer) getRecommendations(ctx context.Context, userID string, productIDs []string) ([]*pb.Product, error) {
+	resp, err := pb.NewRecommendationServiceClient(fe.recommendationSvcConn).ListRecommendations(ctx,
+		&pb.ListRecommendationsRequest{UserId: userID, ProductIds: productIDs})
+	if err != nil {
+		return nil, err
+	}
+	out := make([]*pb.Product, len(resp.GetProductIds()))
+	for i, v := range resp.GetProductIds() {
+		p, err := fe.getProduct(ctx, v)
+		if err != nil {
+			return nil, fmt.Errorf("failed to get recommended product info (#%s): %+v", v, err)
+		}
+		out[i] = p
+	}
+	if len(out) > 4 {
+		out = out[:4] // take only first four to fit the UI
+	}
+	return out, err
+}

src/frontend/templates/cart.html

@@ -14,8 +14,8 @@
                 {{ range $.items }}
                 <div class="row pt-2 mb-2">
                     <div class="col text-right">
-                            <img class="img-fluid" style="width: auto; max-height: 60px;"
-                                src="{{.Item.Picture}}" />
+                            <a href="/product/{{.Item.Id}}"><img class="img-fluid" style="width: auto; max-height: 60px;"
+                                src="{{.Item.Picture}}" /></a>
                     </div>
                     <div class="col align-middle">
                         <strong>{{.Item.Name}}</strong><br/>
@@ -45,6 +45,11 @@
                 </div>
                 {{ end }}
 
+                {{ if $.recommendations}}
+                    <hr/>
+                    {{ template "recommendations" $.recommendations }}
+                {{ end }}
+
             </div>
         </div>
     </main>

src/frontend/templates/footer.html

@@ -1,7 +1,6 @@
 {{ define "footer" }}
     <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js" integrity="sha384-smHYKdLADwkXOn1EmN1qk/HfnUcbVRZyYmZ4qpPea6sjB/pTJ0euyQp0Mk8ck+5T" crossorigin="anonymous"></script>
-
-session-id: {{$.session_id}}
+    <small class="text-muted mx-auto">This is a demo application.</small>
 </body>
 </html>
 {{ end }}

src/frontend/templates/product.html

@@ -6,7 +6,7 @@
             <div class="container bg-light py-3 px-lg-5 py-lg-5">
                 <div class="row">
                     <div class="col-12 col-lg-5">
-                            <img class="img-fluid" style="width: 100%;"
+                            <img class="img-fluid border" style="width: 100%;"
                             src="{{$.product.Item.Picture}}" />
                     </div>
                     <div class="col-12 col-lg-7">
@@ -43,6 +43,10 @@
                     </div>
                 </div>
                 
+                {{ if $.recommendations}}
+                    <hr/>
+                    {{ template "recommendations" $.recommendations }}
+                {{ end }}
                 
             </div>
         </div>

src/frontend/templates/recommendations.html

@@ -0,0 +1,21 @@
+{{ define "recommendations" }}
+<h5 class="text-muted">Similar products</h5>
+<div class="row">
+    {{range . }}
+        <div class="col-3">
+            <div class="card mb-3 box-shadow">
+                <a href="/product/{{.Id}}">
+                    <img class="card-img-top border-bottom" alt =""
+                        style="width: 100%; height: auto;"
+                        src="{{.Picture}}">
+                </a>
+                <div class="card-body text-center py-2">
+                    <small class="card-title text-muted">
+                        {{ .Name }}
+                    </small>
+                </div>
+            </div>
+        </div>
+    {{ end }}
+</div>
+{{ end }}