Implementing retry logic in command host

--HG--
branch : dev

src/Orchard/Commands/CommandHostAgent.cs

@@ -42,14 +42,19 @@ namespace Orchard.Commands {
         }
 
         public int StartHost(TextReader input, TextWriter output) {
-            try {
-                _hostContainer = OrchardStarter.CreateHostContainer(ContainerRegistrations);
-                _tenants = new Dictionary<string, IStandaloneEnvironment>();
 
-                var host = _hostContainer.Resolve<IOrchardHost>();
-                host.Initialize();
+            // This retry logic is not exactly clean, but a change in configuration
+            // sometimes need us to re-try initializing a host container.
+        Retry:
+            try {
+                _hostContainer = CreateHostContainer();
+                _tenants = new Dictionary<string, IStandaloneEnvironment>();
                 return 0;
             }
+            catch (OrchardCommandHostRetryException e) {
+                output.WriteLine("{0} (Retrying...)", e.Message);
+                goto Retry;
+            }
             catch (Exception e) {
                 for (; e != null; e = e.InnerException) {
                     output.WriteLine("Error: {0}", e.Message);
@@ -59,6 +64,14 @@ namespace Orchard.Commands {
             }
         }
 
+        private IContainer CreateHostContainer() {
+            var hostContainer = OrchardStarter.CreateHostContainer(ContainerRegistrations);
+
+            var host = hostContainer.Resolve<IOrchardHost>();
+            host.Initialize();
+            return hostContainer;
+        }
+
 
         public int StopHost(TextReader input, TextWriter output) {
             try {
@@ -133,7 +146,7 @@ namespace Orchard.Commands {
             }
             else {
                 // In case of an unitiliazed site (no default settings yet), we create a default settings instance.
-                var settings = new ShellSettings {Name = "Default", State = new TenantState("Uninitialized")};
+                var settings = new ShellSettings { Name = "Default", State = new TenantState("Uninitialized") };
                 return host.CreateStandaloneEnvironment(settings);
             }
         }

src/Orchard/Commands/CommandHostEnvironment.cs

@@ -1,10 +1,25 @@
 using System;
 using System.Linq;
+using System.Runtime.Serialization;
 using System.Web.Hosting;
 using Orchard.Environment;
 using Orchard.Localization;
 
 namespace Orchard.Commands {
+    public class OrchardCommandHostRetryException : OrchardCoreException {
+        public OrchardCommandHostRetryException(LocalizedString message)
+            : base(message) {
+        }
+
+        public OrchardCommandHostRetryException(LocalizedString message, Exception innerException)
+            : base(message, innerException) {
+        }
+
+        protected OrchardCommandHostRetryException(SerializationInfo info, StreamingContext context)
+            : base(info, context) {
+        }
+    }
+
     public class CommandHostEnvironment : IHostEnvironment {
         public CommandHostEnvironment() {
             T = NullLocalizer.Instance;
@@ -29,7 +44,7 @@ namespace Orchard.Commands {
         }
 
         public void ResetSiteCompilation() {
-            throw new OrchardCoreException(T("A change of configuration requires the application to be restarted. Running the command again usually solves this problem."));
+            throw new OrchardCommandHostRetryException(T("A change of configuration requires the host to be restarted."));
         }
     }
 }