frontend: add home template

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

src/frontend/rpc.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"context"
+
+	pb "frontend/genproto"
+)
+
+func (fe *frontendServer) getCurrencies(ctx context.Context) ([]string, error) {
+	currs, err := pb.NewCurrencyServiceClient(fe.currencySvcConn).
+		GetSupportedCurrencies(ctx, &pb.Empty{})
+	if err != nil {
+		return nil, err
+	}
+	var out []string
+	for _, c := range currs.CurrencyCodes {
+		if _, ok := whitelistedCurrencies[c]; ok {
+			out = append(out, c)
+		}
+	}
+	return out, nil
+}
+
+func (fe *frontendServer) getProducts(ctx context.Context) ([]*pb.Product, error) {
+	resp, err := pb.NewProductCatalogServiceClient(fe.productCatalogSvcConn).
+		ListProducts(ctx, &pb.Empty{})
+	return resp.GetProducts(), err
+}