ASPNET MVC Weird Production Errors - asp.net-mvc

I have an ASPNET MVC application that works fine locally but when I deployed it to production I get the following stack trace.
There are a few puzzling things about this stack trace, for one everything worked fine before i deployed my changes, for two the location of the code is wrong it's now on a production server not my dev machine and for three Rework is a controller method, not an object
2/28/2011 11:03:47 PM COB_Database.Controllers.ClaimsController Rework Object reference
not set to an instance of an object. at COB_Database.ViewModels.ErrorVM.
<>c__DisplayClass12.<.ctor>b__1(Error err) in
C:\Users\jperrine251\documents\visual studio 2010\Projects\COB Database\COB
Database\ViewModels\ErrorVM.cs:line 26 at
System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext() at
System.Collections.Generic.List`1..ctor(IEnumerable`1 collection) at
System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source) at
COB_Database.ViewModels.ErrorVM..ctor(User user, Claim claim, IEnumerable`1 actions,
IEnumerable`1 users, IEnumerable`1 referralReasons, Boolean editing) in
C:\Users\jperrine251\documents\visual studio 2010\Projects\COB Database\COB
Database\ViewModels\ErrorVM.cs:line 26 at
COB_Database.Controllers.ClaimsController.Rework(Int32 id) in
C:\Users\jperrine251\documents\visual studio 2010\Projects\COB Database\COB
Database\Controllers\ClaimsController.cs:line 160 at lambda_method(Closure ,
ControllerBase , Object[] ) at
System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[]
parameters) at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext
controllerContext, IDictionary`2 parameters) at
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext
controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) at
System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass15.
<InvokeActionMethodWithFilters>b__12() at
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter,
ActionExecutingContext preContext, Func`1 continuation) at
System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass15.<>c__DisplayClass17.
<InvokeActionMethodWithFilters>b__14() at
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext
controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2
parameters) at
System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext
controllerContext, String actionName)
Anyone have any ideas?
EDIT: The line in question in the stack trace is this
UsersErrors = claim.Errors.Where(err => err.UserID == user.id && err.ErrorActionID != null &&
err.ErrorActionLogs.OrderByDescending(eal => eal.id).FirstOrDefault().Timestamp >= DateTime.Now.AddHours(-10)).ToList();
And UsersErrors is defined as List<Error> UsersErrors
I tried changing the code to this but still no luck:
var userErrors = claim.Errors.Where(err => err.UserID == user.id && err.ErrorActionID != null &&
err.ErrorActionLogs.OrderByDescending(eal => eal.id).FirstOrDefault().Timestamp >= DateTime.Now.AddHours(-10));
UsersErrors = userErrors == null ? new List<Error>() : userErrors.ToList();
Edit, I've isolated the line causing the problem further, I took the above code and broke it down into predicates and passed those to my linq expression, the following is what is failing (but working locally)
Func<Error, bool> errorLogp =
(err) =>
err.ErrorActionLogs
.OrderByDescending(eal => eal.id)
.FirstOrDefault().Timestamp >= DateTime.Now.AddHours(-10);
Errors have a log of actions taken on them, this is just grabbing the most recent and ensuring it was done in the last 10 hours, I've checked the database for the record i'm testing on and it is present along with an error action log that meets the requirements
EDIT: Also to ensure that claim.Errors isn't null I've done the following
UsersErrors = Claim.Errors == null ?
new List<Error>() :
Claim.Errors.Where(err => errorp(err) && errorLogp(err)).ToList();
but the code still bombs out at the errorLogp predicate Func

Are you jperrine251? If that's not you, your code isn't running on the server. From what I can tell it looks like your error handling code is making some assumptions that don't hold in production and the whole thing is bombing out. Be very defensive in your error handling.
Posting applicable code from ErrorVM and ClaimsController would be helpful too.

A few things to consider:
The location of the code is from the PDB (symbol) files that you compiled on your machine. It doesn't update when you deploy to a different environment. The location does give you an exact line number to investigate though, which is good. (For future production releases, you will want to compile your code in release mode and not debug mode.)
The exception message is "Object reference not set to an instance of an object." This exception isn't telling you that Rework is an object, but that during the rework action a NullReferenceException was thrown. Somewhere on line 26 of ErrorVM.cs you have a variable that is null and you're trying to access one of its members.

The location is where the code was compiled and therefore it's normal that it has your development path (not the production box since the source code was never on that box)
As far as the error it looks like you have a null reference inside the ErrorVM
ViewModels\ErrorVM.cs:line 26 at
It might be that the original error is being composed during the process of displaying the error view (?)

I found the problem, looks like there was some data missing from the database that was expected to be there, thanks for all the help everyone

Related

Unity and Random "Index was outside the bounds of the array" exception

We are running web site with around 15.000 realtime user (google analytics) (Around 1000 request/sec (perf counters)).
We have two web server behind load balancer.
Sometimes every day sometimes 1 time in a week one of our web servers stop execute requests and start to response with error and every request is logging following exception:
"System.IndexOutOfRangeException - Index was outside the bounds of the array."
Our environment : IIS 8.5, .Net 4.5.0, Mvc 5.1.0, Unity 3.5 (same state with 3.0), WebActivatorEx 2.0
In IIS, Worker Process 1 and other settings are with defaults.
We could not catch any specific scenario made this error. After App pool recycle everything start with no problem. And before every request respond with error, there is not any error related with it.
There is one question asked in the past with related old Unity version:
https://unity.codeplex.com/discussions/328841
http://unity.codeplex.com/workitem/11791
Could not see anything I can do about it.
Here exception details:
System.IndexOutOfRangeException
Index was outside the bounds of the array.
System.IndexOutOfRangeException: Index was outside the bounds of the array.
at System.Collections.Generic.List`1.Enumerator.MoveNext()
at System.Linq.Enumerable.WhereListIterator`1.MoveNext()
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at Microsoft.Practices.Unity.NamedTypesRegistry.RegisterType(Type t, String name)
at Microsoft.Practices.Unity.UnityDefaultBehaviorExtension.OnRegisterInstance(Object sender, RegisterInstanceEventArgs e)
at System.EventHandler`1.Invoke(Object sender, TEventArgs e)
at Microsoft.Practices.Unity.UnityContainer.RegisterInstance(Type t, String name, Object instance, LifetimeManager lifetime)
at Microsoft.Practices.Unity.UnityContainerExtensions.RegisterInstance[TInterface](IUnityContainer container, TInterface instance, LifetimeManager lifetimeManager)
at DemoSite.News.Portal.UI.App_Start.UnityConfig.<>c__DisplayClass1.<RegisterTypes>b__0()
at DemoSite.News.Portal.Core.Controller.BaseController.Initialize(RequestContext requestContext)
at System.Web.Mvc.Controller.BeginExecute(RequestContext requestContext, AsyncCallback callback, Object state)
at System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__4(AsyncCallback asyncCallback, Object asyncState, ProcessRequestState innerState)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallBeginDelegate(AsyncCallback callback, Object callbackState)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.Begin(AsyncCallback callback, Object state, Int32 timeout)
at System.Web.Mvc.Async.AsyncResultWrapper.Begin[TState](AsyncCallback callback, Object callbackState, BeginInvokeDelegate`1 beginDelegate, EndInvokeVoidDelegate`1 endDelegate, TState invokeState, Object tag, Int32 timeout, SynchronizationContext callbackSyncContext)
at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
My configuration is as follows:
public static void RegisterTypes(IUnityContainer container)
{
var section = (UnityConfigurationSection)ConfigurationManager.GetSection("unity");
container.LoadConfiguration(section);
ServiceLocator.SetLocatorProvider(() => new UnityServiceLocator(container));
}
Initialize method as follow:
protected override void Initialize(System.Web.Routing.RequestContext requestContext)
{
if (requestContext.RouteData.Values["ViewActionId"] != null)
{
int viewActionId;
if (!int.TryParse(requestContext.RouteData.Values["ViewActionId"].ToString(), out viewActionId))
return;
var cacheProvider = ServiceLocator.Current.GetInstance<ICacheProvider>();
List<ViewActionClass> viewActionClasses = null;
string cacheKey = CacheKeyCompute.ComputeCacheKey("ViewActionClass", CacheKeyTypes.DataCache,
new KeyValuePair<string, string>("viewActionId", viewActionId.ToString()));
_configuration = ServiceLocator.Current.GetInstance<IConfiguration>();
viewActionClasses =
cacheProvider.AddOrGetExistingWithLock<List<ViewActionClass>>(cacheKey, () =>
{
var viewActionClassBusiness =
ServiceLocator.Current.GetInstance<IViewActionClassBusiness>();
return viewActionClassBusiness.ViewActionClassGetByViewActionId(viewActionId);
});
ViewBag.ActionClass = viewActionClasses;
ViewBag.Configuration = _configuration;
}
base.Initialize(requestContext);
}
Registration xml for ICacheProvider, IConfiguration and IViewActionClassBusiness
<type type="DemoSite.Runtime.Caching.ICacheProvider, DemoSite.Core"
mapTo="DemoSite.Runtime.Caching.ObjectCacheProvider, DemoSite.Core">
<lifetime type="containerControlledLifetimeManager" />
</type>
<type type="DemoSite.Core.Configuration.IConfiguration, DemoSite.Core"
mapTo="DemoSite.Core.Configuration.ConfigFileConfiguration, DemoSite.Core">
<lifetime type="containerControlledLifetimeManager" />
</type>
<type type="DemoSite.News.Business.IViewActionClassBusiness, DemoSite.News.Business"
mapTo="DemoSite.News.Business.Default.ViewActionClassBusiness, DemoSite.News.Business.Default">
<lifetime type="perRequestLifetimeManager" />
</type>
Maybe it is related with high traffic.
Is there anyone encounter a problem like that and any solution ?
Thanks in advance
As far as I can see from the stack trace you are registering instances in the container during the web request. The RegisterType and RegisterInstance methods are not thread-safe in Unity (and this probably holds for most DI libraries in .NET). This explains why this is happening to at random points and under high load.
It is good practice to register your container only at start-up and don't change it later on. With the Dependency Inversion Principle and Dependency Injection pattern in particular you try to centralize the knowledge of how object graphs are wired, but you are decentralizing it again by doing new registrations later on. And even if registration was thread-safe with Unity, it's still very likely that you introduce race conditions by changing registrations during runtime.
UPDATE
Your code has the following code that causes the problems:
ServiceLocator.SetLocatorProvider(() => new UnityServiceLocator(container));
This seems very innocent, but in fact it causes both a concurrency bug and a memory leak.
Because the new statement is inside the lambda, it will cause a new UnityServiceLocator to be created every time you call ServiceLocator.Current. That wouldn't be bad by itself, but the UnityServiceLocator's constructor makes a call to container.RegisterInstance to register itself in the container. But as I already said: calling RegisterInstance` is not thread-safe.
But even if it was thread-safe, it still causes a memory leak in your application, since a call to RegisterInstance will not replace an existing registration, but appends it to a list of registrations. This means that the list of UnityServiceLocator instances in the container will keep growing and will eventually cause the system to crash with an OutOfMemoryException. You are actually lucky that you hit this concurrency bug first, because the OOM bug would be much harder to trace back.
The fix is actually very simple: move the construction of the UnityServiceLocator out of the lambda and return that single instance every time:
var locator = new UnityServiceLocator(container);
ServiceLocator.SetLocatorProvider(() => locator);
The behavior of the UnityServiceLocator is a design flaw in my opinion, because since RegisterInstance is not thread-safe and the UnityServiceLocator has no idea how many times it is created, it should never call RegisterInstance from within its constructor -or at least- not without doing a check whether it is safe to register that instance.
Problem however is that removing that call to RegisterInstance is a breaking change, but still probably the best solution for the Unity team. Most users will probably not notice the missing IServiceLocator registration anyway and if they do, Unity will communicate a clear exception message in that case. Another option would be to let the UnityServiceLocator check whether any instances have already been resolved from the container, and in that case throw an InvalidOperationException from within the UnityServiceLocator's constructor.

Why does IIS Express Restart my App Pool in MVC Application

I have a fairly complex MVC Application which must initialize when the Application starts. I am trying to diagnose why the App pool is restarting after the first MVC page is rendered. To diagnose this issue, I put break points on Application_Start and Application_End. Applicaiton_Start is called as expected. At the end of the first returned HTML/Razor page from my application, Application_End is called. On the next page request, Application_Start get called again, and then seems to run as expected without restarting.
I thought this was caused by Razor compiling the views at runtime, which would then updating the BIN foldee. I know that IIS and IIS Express restart the APP pool when the BIN folder is updated, so I assumed this MVC Razor compllation was causing the IIS process to restart the app pool. To mitigate this, I followed the instructions here: https://chrismckee.co.uk/asp-net-mvc-compiled-views/ to pre-compile my Razor views. I know that the vies are now pre-compiled, as this did locate several compile issues [compile errors] that would not have been found until runtime without these configuration changes resulting in the pre-complication of the Razor views.
So the question is this:
1) How Can I diagnose why the app pool is restarting?
2) Does anyone know why this happens in and MVC application running in IISExpress?
[... and obviously, how to prevent it from happening]
Thanks
jloper
Update #2:
I looked up Browser Link and figured out quickly that it not necessary and really not being used. I turn off BrowserLink and sure enough, the exception goes away. Now the Application_Start is called as expected, Application_End is called [and no exception has occurred (System.GetLastError() returns null]. Application_Exception is NEVER called. Application_Start is called a second time.
All state of the application is reset when the Application_End is called.
Update #1:
As suggested, I added Application_Error and retrieved the last exception using Server.GetLastError(). Here is the exception that was returned:
The thread 0xc4c has exited with code 259 (0x103).
System.Web.HttpException (0x80004005): The controller for path '/__browserLink/requestData/8cf754f80e264fd392f4a0fbffea67e4' was not found or does not implement IController.
at System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType)
at System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName)
at System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory)
at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state)
at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state)
at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
Also, I added the same code to Application_End. At the point that Application_End is being called, System.GetLastError() return nulls.
I found a trick somewhere on the web (forget where) that you can use reflection to get the reason in the application_end event:
Sub Application_End(sender As Object, e As EventArgs)
Dim runtime As HttpRuntime = CType(GetType(HttpRuntime).InvokeMember("_theRuntime", Reflection.BindingFlags.NonPublic Or Reflection.BindingFlags.Static Or Reflection.BindingFlags.GetField, Nothing, Nothing, Nothing), HttpRuntime)
Dim shutDownMessage = CType(runtime.GetType().InvokeMember("_shutDownMessage", Reflection.BindingFlags.NonPublic Or Reflection.BindingFlags.Instance Or Reflection.BindingFlags.GetField, Nothing, runtime, Nothing), String)
Dim shutDownStack = CType(runtime.GetType().InvokeMember("_shutDownStack", Reflection.BindingFlags.NonPublic Or Reflection.BindingFlags.Instance Or Reflection.BindingFlags.GetField, Nothing, runtime, Nothing), String)
'Log reason
outside of adding IIS tracing, this was a code-specific way that I was able to extract the reason...
Brian Main's answer worked perfectly, showing me the message that a file changed in the project folder, which caused a restart.
For those interested, here is the C# version.
var runtime = typeof (HttpRuntime).InvokeMember("_theRuntime", BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.GetField, null, null, null);
var shutDownMessage = runtime.GetType().InvokeMember("_shutDownMessage", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField, null, runtime, null);
var shutDownStack = runtime.GetType().InvokeMember("_shutDownStack", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField, null, runtime, null);
Your problem is a bug in Visual Studio's "Browser Link" feature. This was fixed in an update. Apply the latest Update (Update 4) to Visual Studio 2013 and your problem should be fixed.

Why are my controllers being instantiated when they're not being called?

Here are the symptoms I am experiencing:
I have a brand new empty controller in an area:
public class JamController : Controller
{
public JamController()
{
throw new Exception("Not implemented!");
}
If I visit http://myprojectserver.example.com:12345/urlthatdoesnotexist, I get the following error:
[CompositionException: The composition produced a single composition error. The root cause is provided below. Review the CompositionException.Errors property for more detailed information.
1) Not implemented!
Resulting in: An exception occurred while trying to create an instance of type 'MyWebProject.Areas.Users.Controllers.JamController'.
Resulting in: Cannot activate part 'MyWebProject.Areas.Users.Controllers.JamController'.
Element: MyWebProject.Areas.Users.Controllers.JamController --> MyWebProject.Areas.Users.Controllers.JamController
Resulting in: Cannot get export 'MyWebProject.Areas.Users.Controllers.JamController (ContractName="System.Web.Mvc.IController")' from part 'MyWebProject.Areas.Users.Controllers.JamController'.
Element: MyWebProject.Areas.Users.Controllers.JamController (ContractName="System.Web.Mvc.IController")
]
System.ComponentModel.Composition.Hosting.CompositionServices.GetExportedValueFromComposedPart(ImportEngine engine, ComposablePart part, ExportDefinition definition) +55
System.ComponentModel.Composition.Hosting.CatalogExportProvider.GetExportedValue(CatalogPart part, ExportDefinition export, Boolean isSharedPart) +78
System.ComponentModel.Composition.Hosting.CatalogExport.GetExportedValueCore() +47
System.ComponentModel.Composition.Primitives.Export.get_Value() +57
System.ComponentModel.Composition.ExportServices.GetCastedExportedValue(Export export) +40
System.ComponentModel.Composition.<>c__DisplayClassa`1.<CreateStronglyTypedLazyOfT>b__6() +39
System.Lazy`1.CreateValue() +416
System.Lazy`1.LazyInitValue() +382
System.Lazy`1.get_Value() +75
MefContrib.Web.Mvc.<>c__DisplayClass4.<GetControllerType>b__0(Lazy`1 e) +53
System.Linq.WhereSelectEnumerableIterator`2.MoveNext() +204
System.Collections.Generic.List`1..ctor(IEnumerable`1 collection) +381
System.Linq.Enumerable.ToList(IEnumerable`1 source) +58
MefContrib.Web.Mvc.CompositionControllerFactory.GetControllerType(RequestContext requestContext, String controllerName) +412
System.Web.Mvc.DefaultControllerFactory.System.Web.Mvc.IControllerFactory.GetControllerSessionBehavior(RequestContext requestContext, String controllerName) +61
System.Web.Mvc.MvcRouteHandler.GetSessionStateBehavior(RequestContext requestContext) +122
System.Web.Mvc.MvcRouteHandler.GetHttpHandler(RequestContext requestContext) +33
System.Web.Mvc.MvcRouteHandler.System.Web.Routing.IRouteHandler.GetHttpHandler(RequestContext requestContext) +10
System.Web.Routing.UrlRoutingModule.PostResolveRequestCache(HttpContextBase context) +9709884
System.Web.Routing.UrlRoutingModule.OnApplicationPostResolveRequestCache(Object sender, EventArgs e) +82
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +136
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +699
My question is "Why?" Why on earth is it trying to instantiate this controller? Where do I look to determine what is causing this. I'm pretty sure it isn't expected behaviour to instantiate every controller on "page not found".
I'm at a loss to know where to look. Can someone point me in the direction of something that will help?
UPDATE:
Turns out that the SetControllerFactory method below is causing the issue:
// Tell MVC3 to use MEF as its dependency resolver.
var dependencyResolver = new CompositionDependencyResolver(catalog);
DependencyResolver.SetResolver(dependencyResolver);
// Tell MVC3 to resolve dependencies in controllers
ControllerBuilder.Current.SetControllerFactory(
new CompositionControllerFactory(
new CompositionControllerActivator(dependencyResolver)));
Commenting out the "Tell MVC3 to resolve dependencies in controllers" section fixes my issue, and no controllers except those I ask for get instantiated. Luckily, that's only needed if you're not using the standard Asp.Net controller resolution (and we are).
This is down to a bug in MefContrib.Web.Mvc. This assembly implements it's own ControllerFactory that inherits from DefaultControllerFactory.
The factory overrides GetControllerType, I assume to try and resolve controllers that live in assemblies somewhere other than the default application or it's references. The implementation of GetControllerType first calls into base.GetControllerType to see if Defaultcontroller can resolve it.
If it can't - which is the case for urls that don't exist - it asks MEF for all exports that implement IController. This returns an IEnumerable<Lazy<IController>> with one item for every class that implements IController in the bin/ folder (by default).
It then runs a linq query over the IEnumerable, calling GetType() on the Value property of each Lazy<IController>. Requesting the Value of a Lazy<T> forces the instance to be created. This is why every controller in the bin/ is being constructed for a page that doesn't exist.
I don't think this is an easy problem to fix properly as there is no way of getting the Type instance from Lazy<T>.Value without creating the value. However by removing the lines from AppStart_MefContribMVC3.cs that register the ControllerFactory with Asp.Net - you have effectively stopped using MefContrib.Web.Mvc's ControllerFactory and just used Asp.Net's DefaultControllerFactory instead.
Turns out that the SetControllerFactory method below is causing the issue:
// Tell MVC3 to use MEF as its dependency resolver.
var dependencyResolver = new CompositionDependencyResolver(catalog);
DependencyResolver.SetResolver(dependencyResolver);
// Tell MVC3 to resolve dependencies in controllers
ControllerBuilder.Current.SetControllerFactory(
new CompositionControllerFactory(
new CompositionControllerActivator(dependencyResolver)));
Commenting out the "Tell MVC3 to resolve dependencies in controllers" section fixes my issue, and no controllers except those I ask for get instantiated. Luckily, that's only needed if you're not using the standard Asp.Net controller resolution (and we are).

ASP.NET MVC Application crashing randomly

I created a MVC 2 Application to work as a RSS Feeder and deliver News Contents for a number of applications to consume.
Everything was doing fine until yesterday when suddenly my application started throwing a random error which doesn't tell me much of what's going on (or at least I don't understand it).
This error only occurs in Production and cannot be reproduced in staging or my local machine.
Here's the stack trace:
Error executing child request for handler
'System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerWrapper'.errorPath:/Android/Edition/2011-11-22/P1
HostIP:##.##.##.## at
System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler,
TextWriter writer, Boolean preserveForm, Boolean setPreviousPage,
VirtualPath path, VirtualPath filePath, String physPath, Exception
error, String queryStringOverride) at
System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter
writer, Boolean preserveForm, Boolean setPreviousPage) at
System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter
writer, Boolean preserveForm) at
System.Web.HttpServerUtilityWrapper.Execute(IHttpHandler handler,
TextWriter writer, Boolean preserveForm) at
System.Web.Mvc.ViewPage.RenderView(ViewContext viewContext) at
System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)
at System.Web.Mvc.ControllerActionInvoker.<>c_DisplayClass14.b_11()
at
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter
filter, ResultExecutingContext preContext, Func1 continuation) at
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter
filter, ResultExecutingContext preContext, Func1 continuation) at
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext
controllerContext, IList1 filters, ActionResult actionResult) at
System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext
controllerContext, String actionName) at
System.Web.Mvc.Controller.ExecuteCore() at
System.Web.Mvc.MvcHandler.<>c__DisplayClass8.b__4() at
System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.b__0() at
System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass81.b__7(IAsyncResult
_) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End() at
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
at
System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step,
Boolean& completedSynchronously)
This error only occurs sometimes and can throw at any action of any controller.
I would like to have found the reason in a specific action but it only throws sometimes and can throw for any action.
Such byzantine errors are hard to debug. The stack trace you're seeing does not help in diagnosing the error.
First, you should improve error logging. In your global.asax, create an implementation of the Application_Error hook that logs the exception and all inner exceptions to a file (I wouldn't log this to the database, because the db connection could be the culprit). Make sure that this code is solid: it should focus on these critical errors and not log every 404 page. Also, make sure that the logging code itself does not create any problems (it should be highly error tolerant).
The cause for this kind of problems is usually access to some kind of static variables. Out of all keywords, I believe static is by far the most dangerous one because it is so subtle.
Some common errors I've seen.
Caching Someone wanted to be smart and cache some data in a static dictionary or so. Unfortunately, the locking code is flawed. An exception occurs only if the code for some user tries to add sth. to the cache, but it's already there:
if(_dict.ContainsKey(cacheKey) == false)
{
// second thread adds data to the dictionary here
_dict.Add(cacheKey, cacheData); // exception
}
This can also happen in a 3rd party library that uses caching or pooling. Access static variables with care.
Uncommon Code Paths Something unusual happens that calls code that is not called very often, and that code is flawed. If you have testing with high code coverage, check the spots that are not covered by the tests.
DB Connection Lost A socket reset on the db connection could lead to exceptions. Many database connection libraries / drivers fix this quickly (i.e. the next request will be fine). This is hard to handle; basically it shouldn't happen but there are many reasons why it could occur.
This error tells you, that the true error is somewhere in some child action, that is action rendered by Html.RenderAction().
There is no such thing as "random" error - there has to be scenario where it happens, you just dont know it because the conditions vary maybe.
You should identify all your child actions, and test them with various inputs.. after you identify the problematic input set, try disabling child actions one by one and find the error this way.

using glimpse and structuremap together

I'm adding structuremap to my project for DI/IOC. I built a demo project to get familiar with it before adding it to my application. After getting it working in the demo I started moving it into my app.
I also use glimpse, and that seems to be the only thing causing problems since the structure map addition (so far).
I followed a pretty basic SM tutorial and the NuGet package, and at this point I'm not even injecting any dependencies yet. Just getting everything wired up.
Here's my application_start
IContainer container = new Container(x =>
{
x.For<IControllerActivator>().Use<StructureMapControllerActivator>();
});
DependencyResolver.SetResolver(new SmDependencyResolver(container));
If I disable glimpse, my application works as it did before. I'd be ready to start doing DI. But if I leave glimpse enabled I get a null object exception. Here's the stack trace, I'm not having much luck following it.
System.NullReferenceException: Object reference not set to an instance of an object.
at Glimpse.Mvc3.Interceptor.ActionInvokerProxyGenerationHook.NonProxyableMemberNotification(Type type, MemberInfo memberInfo)
at Castle.DynamicProxy.Contributors.MembersCollector.AcceptMethod(MethodInfo method, Boolean onlyVirtuals, IProxyGenerationHook hook)
at Castle.DynamicProxy.Contributors.ClassMembersCollector.GetMethodToGenerate(MethodInfo method, IProxyGenerationHook hook, Boolean isStandalone)
at Castle.DynamicProxy.Contributors.MembersCollector.AddMethod(MethodInfo method, IProxyGenerationHook hook, Boolean isStandalone)
at Castle.DynamicProxy.Contributors.MembersCollector.AddProperty(PropertyInfo property, IProxyGenerationHook hook)
at Castle.DynamicProxy.Contributors.MembersCollector.CollectProperties(IProxyGenerationHook hook)
at Castle.DynamicProxy.Contributors.MembersCollector.CollectMembersToProxy(IProxyGenerationHook hook)
at Castle.DynamicProxy.Contributors.ClassProxyTargetContributor.<CollectElementsToProxyInternal>d__2.MoveNext()
at Castle.DynamicProxy.Contributors.CompositeTypeContributor.CollectElementsToProxy(IProxyGenerationHook hook, MetaType model)
at Castle.DynamicProxy.Generators.ClassProxyGenerator.GenerateType(String name, Type[] interfaces, INamingScope namingScope)
at Castle.DynamicProxy.Generators.BaseProxyGenerator.ObtainProxyType(CacheKey cacheKey, Func`3 factory)
at Castle.DynamicProxy.ProxyGenerator.CreateClassProxy(Type classToProxy, Type[] additionalInterfacesToProxy, ProxyGenerationOptions options, Object[] constructorArguments, IInterceptor[] interceptors)
at Glimpse.Mvc3.Extensions.ControllerExtentions.TrySetActionInvoker(IController iController, IGlimpseLogger logger)
at System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, ref IController controller, ref IControllerFactory factory)
at System.Web.Mvc.MvcHandler.<>c__DisplayClass6.<BeginProcessRequest>b__2()
at System.Web.Mvc.SecurityUtil.<>c__DisplayClassb`1.<ProcessInApplicationTrust>b__a()
at System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Func`1 func)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, ref Boolean completedSynchronously)
Based on your callstack, it looks like you are using an older version of Glimpse.
This bug was fixed in version 0.85 of Glimpse, available now on NuGet and CodePlex. Upgrading should fix your problem.

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