Merge pull request glennc#1 from glennc/shirhatti/counters

Add total-orders EventCounter

src/BlazingPizza.Orders/OrdersController.cs

@@ -49,6 +49,7 @@ public async Task<ActionResult<Guid>> PlaceOrder(Order order)
             order.OrderId = Guid.NewGuid();
             order.TotalPrice = order.GetFormattedTotalPrice();
             await _db.SaveOrder(order);
+            OrdersEventSource.Log.OrderCreated();
             return order.OrderId;
         }
     }

src/BlazingPizza.Orders/OrdersEventSource.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Tracing;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace BlazingPizza.Orders
+{
+    internal sealed class OrdersEventSource : EventSource
+    {
+        public static readonly OrdersEventSource Log = new OrdersEventSource();
+
+        private PollingCounter _totalOrdersCounter;
+
+        private long _totalOrders;
+
+        internal OrdersEventSource()
+            : base("BlazingOrders.Pizza")
+        {
+
+        }
+
+        internal void OrderCreated()
+        {
+            Interlocked.Increment(ref _totalOrders);
+        }
+
+        protected override void OnEventCommand(EventCommandEventArgs command)
+        {
+            if (command.Command == EventCommand.Enable)
+            {
+                _totalOrdersCounter ??= new PollingCounter("total-orders", this, () => _totalOrders)
+                {
+                    DisplayName = "Total Orders"
+                };
+            }
+        }
+    }
+}

src/BlazingPizza.Orders/Startup.cs

@@ -12,6 +12,7 @@
 using Microsoft.Extensions.Logging;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.AspNetCore.Authentication.Cookies;
+using Microsoft.ApplicationInsights.Extensibility.EventCounterCollector;
 
 namespace BlazingPizza.Orders
 {
@@ -31,6 +32,11 @@ public void ConfigureServices(IServiceCollection services)
             services.AddControllers();
             services.AddGrpc();
             services.AddApplicationInsightsTelemetry(Configuration);
+
+            services.ConfigureTelemetryModule<EventCounterCollectionModule>((module, options) =>
+            {
+                module.Counters.Add(new EventCounterCollectionRequest("BlazingOrders.Pizza", "total-orders"));
+            });
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.