Updated approach for restarting the instance on configuration changes

MRCollective · May 18, 2014 · b933b51 · MattDavies · May 18, 2014 · b933b51
1 parent cc806ee
commit b933b51
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Showing 2 changed files with 29 additions and 1 deletion.
diff --git a/AzureWebFarm/Config/AzureConfig.cs b/AzureWebFarm/Config/AzureConfig.cs
@@ -1,11 +1,13 @@
 using System;
 using System.Configuration;
 using System.IO;
+using System.Linq;
 using System.Net;
 using System.Security.AccessControl;
 using System.Security.Principal;
 using AzureWebFarm.Helpers;
 using Microsoft.WindowsAzure;
+using Microsoft.WindowsAzure.ServiceRuntime;
 using Microsoft.WindowsAzure.Storage;
 
 namespace AzureWebFarm.Config
@@ -21,6 +23,18 @@ public static void ConfigureRole()
             // Allow multiple simultaneous HTTP request threads
             ServicePointManager.DefaultConnectionLimit = 12;
 
+            AzureRoleEnvironment.Changed += (sender, arg) =>
+            {
+                // Restart the instance on any configuration change given we need to reinitialise our services
+
+                // https://alexandrebrisebois.wordpress.com/2013/09/29/handling-cloud-service-role-configuration-changes-in-windows-azure/
+                // http://msdn.microsoft.com/en-us/library/microsoft.windowsazure.serviceruntime.roleenvironment.changing.aspx
+                if ((arg.Changes.Any(change => change is RoleEnvironmentConfigurationSettingChange)))
+                {
+                    arg.Cancel = true;
+                }
+            };
+
             // Configure local resources
             var localTempPath = GetLocalResourcePathAndSetAccess(TempLocalResource);
             GetLocalResourcePathAndSetAccess(SitesLocalResource);

diff --git a/AzureWebFarm/Helpers/AzureRoleEnvironment.cs b/AzureWebFarm/Helpers/AzureRoleEnvironment.cs
@@ -20,7 +20,21 @@ public static class AzureRoleEnvironment
         public static Action RequestRecycle = () => RoleEnvironment.RequestRecycle();
         public static Func<string, string> GetLocalResourcePath = resourceName => RoleEnvironment.GetLocalResource(resourceName).RootPath.TrimEnd('\\');
         public static Func<bool> HasWebDeployLease = () => CheckHasWebDeployLease();
-
+
+        static AzureRoleEnvironment()
+        {
+            RoleEnvironment.Changing += OnChanging;
+        }
+
+        public static event EventHandler<RoleEnvironmentChangingEventArgs> Changed;
+
+        public static void OnChanging(object caller, RoleEnvironmentChangingEventArgs args)
+        {
+            var handler = Changed;
+            if (handler != null)
+                handler(caller, args);
+        }
+
         public static CloudBlockBlob WebDeployLeaseBlob()
         {
             var blob = CachedWebDeployLeaseBlob ?? GetWebDeployLeaseBlob();