CartService: Add health check endpoint and update routes

Added a new HealthZ endpoint in the Cart Service that responds to HTTP GET requests with a 200 status. Also restructured the existing routes for clarity and better organization, prefixing all cart-related endpoints with '/cart'. Finally, updated the .http file to reflect these changes.

cart-service/cart-service.http

@@ -1,14 +1,22 @@
-GET http://localhost:8081/1/
+GET http://localhost:8080/
 Accept: application/json
 
-###
-PUT http://localhost:8081/1/
+### Health probe
+GET http://localhost:8080/healthz
+Accept: application/json
+
+### Get cart with id=1
+GET http://localhost:8081/cart/1/
+Accept: application/json
+
+### Update cart with id=1
+PUT http://localhost:8081/cart/1/
 Content-Type: application/json
 
 {
   "items": ["1", "2", "3"]
 }
 
-###
-DELETE http://localhost:8081/1/
+### Delete cart with id=1
+DELETE http://localhost:8081/cart/1/
 Accept: application/json

cart-service/handler/HealthZ.go

@@ -0,0 +1,10 @@
+package handler
+
+import (
+	"github.com/gin-gonic/gin"
+	"net/http"
+)
+
+func HealthZ(c *gin.Context) {
+	c.Status(http.StatusOK)
+}

cart-service/main.go

@@ -58,9 +58,16 @@ func loadApiServer() {
 		MaxAge: 12 * time.Hour,
 	}))
 
-	Router.GET("/:cartId/", handler.GetCart)
-	Router.PUT("/:cartId/", handler.UpdateCart)
-	Router.DELETE("/:cartId/", handler.DeleteCart)
+	Router.Use(
+		gin.LoggerWithWriter(gin.DefaultWriter, "/healthz"),
+		gin.Recovery(),
+	)
+
+	Router.GET("/", handler.HealthZ)
+	Router.GET("/healthz", handler.HealthZ)
+	Router.GET("/cart/:cartId/", handler.GetCart)
+	Router.PUT("/cart/:cartId/", handler.UpdateCart)
+	Router.DELETE("/cart/:cartId/", handler.DeleteCart)
 
 	listenAddress := viper.GetString("listen")
 	err := Router.Run(listenAddress)