ASP.NET Debugging

Windows Azure remote access stops working

ASP.NET Debugging — Mon, 07 May 2012 15:47:49 GMT

Problem

There is an issue where remote access (RDP) can stop working all of a sudden to all instances of a deployment that are running in Azure. The problem is that the process that handles RDP requests has crashed. If you have Windows Azure Diagnostics enabled and gather the event log files, you will see the following entries in the Application Event log:

Log Name: Application
Source: Application Error
Date: 3/19/2012 11:42:43 PM
Event ID: 1005
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: RD00155D3A1AF9
Description:
Windows cannot access the file for one of the following reasons: there is a problem with the network connection, the disk that the file is stored on, or the storage drivers installed on this computer; or the disk is missing. Windows closed the program Windows Azure Remote Desktop Forwarder because of this error.
Program: Windows Azure Remote Desktop Forwarder
File: 
The error value is listed in the Additional Data section.
User Action
1. Open the file again. This situation might be a temporary problem that corrects itself when the program runs again.
2. If the file still cannot be accessed and
- It is on the network, your network administrator should verify that there is not a problem with the network and that the server can be contacted.
- It is on a removable disk, for example, a floppy disk or CD-ROM, verify that the disk is fully inserted into the computer.
3. Check and repair the file system by running CHKDSK. To run CHKDSK, click Start, click Run, type CMD, and then click OK. At the command prompt, type CHKDSK /F, and then press ENTER.
4. If the problem persists, restore the file from a backup copy.
5. Determine whether other files on the same disk can be opened. If not, the disk might be damaged. If it is a hard disk, contact your administrator or computer hardware vendor for further assistance.
Additional Data
Error value: C000026E
Disk type: 0
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Application Error" />
<EventID Qualifiers="49152">1005</EventID>
<Level>2</Level>
<Task>100</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2012-03-19T23:42:43.000Z" />
<EventRecordID>713</EventRecordID>
<Channel>Application</Channel>
<Computer>RD00155D3A1AF9</Computer>
<Security />
</System>
<EventData>
<Data>
</Data>
<Data>Windows Azure Remote Desktop Forwarder</Data>
<Data>C000026E</Data>
<Data>0</Data>
</EventData>
</Event>

Log Name: Application
Source: Application Error
Date: 3/19/2012 11:42:43 PM
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: RD00155D3A1AF9
Description:
Faulting application RemoteForwarderAgent.exe, version 6.0.6002.18314, time stamp 0x4eb31078, faulting module mscorlib.ni.dll, version 2.0.50727.4216, time stamp 0x4e154615, exception code 0xc0000006, fault offset 0x000000000039cd2b, process id 0xa44, application start time 0x01cd016989a1c16d.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Application Error" />
<EventID Qualifiers="0">1000</EventID>
<Level>2</Level>
<Task>100</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2012-03-19T23:42:43.000Z" />
<EventRecordID>712</EventRecordID>
<Channel>Application</Channel>
<Computer>RD00155D3A1AF9</Computer>
<Security />
</System>
<EventData>
<Data>RemoteForwarderAgent.exe</Data>
<Data>6.0.6002.18314</Data>
<Data>4eb31078</Data>
<Data>mscorlib.ni.dll</Data>
<Data>2.0.50727.4216</Data>
<Data>4e154615</Data>
<Data>c0000006</Data>
<Data>000000000039cd2b</Data>
<Data>a44</Data>
<Data>01cd016989a1c16d</Data>
</EventData>
</Event>
Log Name: Application
Source: Application Error
Date: 3/21/2012 1:52:20 PM
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: RD00155D3A2303
Description:
Faulting application RemoteForwarderAgent.exe, version 6.0.6002.18314, time stamp 0x4eb31078, faulting module mscorwks.dll, version 2.0.50727.4216, time stamp 0x4e154582, exception code 0xc0000006, fault offset 0x00000000001a8892, process id 0x%9, application start time 0x%10.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Application Error" />
<EventID Qualifiers="0">1000</EventID>
<Level>2</Level>
<Task>100</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2012-03-21T13:52:20.000Z" />
<EventRecordID>709</EventRecordID>
<Channel>Application</Channel>
<Computer>RD00155D3A2303</Computer>
<Security />
</System>
<EventData>
<Data>RemoteForwarderAgent.exe</Data>
<Data>6.0.6002.18314</Data>
<Data>4eb31078</Data>
<Data>mscorwks.dll</Data>
<Data>2.0.50727.4216</Data>
<Data>4e154582</Data>
<Data>c0000006</Data>
<Data>00000000001a8892</Data>
</EventData>
</Event>

Looking at these messages, you can see that the RemoteForwarderAgent.exe has crashed. This means that no connections can be made to the Windows Azure instances through RDP.

Solution

To resolve this, you need to reboot the deployment from the Windows Azure portal.

Windows Azure worker role crashing

ASP.NET Debugging — Mon, 07 May 2012 15:10:32 GMT

Problem

We have seen an issue where a worker role running inside Windows Azure will crash, especially if it is under heavy load. The problem is with IntelliTrace being enabled. To determine if this is causing your worker role to crash, the first thing to look for are some event logs that look like this:

Application: WaWorkerHost.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Runtime.CallbackException
Stack:
   at System.Runtime.Fx+IOCompletionThunk.UnhandledExceptionFrame(UInt32, UInt32, System.Threading.NativeOverlapped*)
   at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32, UInt32, System.Threading.NativeOverlapped*)

Log Name:      Application
Source:        .NET Runtime
Date:          10/4/2011 3:16:01 PM
Event ID:      1026
Task Category: None
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      RD00155D3203F9
Description:
Application: WaWorkerHost.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Runtime.CallbackException
Stack:
   at System.Runtime.Fx+IOCompletionThunk.UnhandledExceptionFrame(UInt32, UInt32, System.Threading.NativeOverlapped*)
   at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32, UInt32, System.Threading.NativeOverlapped*)

Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name=".NET Runtime" />
    <EventID Qualifiers="0">1026</EventID>
    <Level>2</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2011-10-04T15:16:01.000Z" />
    <EventRecordID>426</EventRecordID>
    <Channel>Application</Channel>
    <Computer>RD00155D3203F9</Computer>
    <Security />
  </System>
  <EventData>
    <Data>Application: WaWorkerHost.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Runtime.CallbackException
Stack:
   at System.Runtime.Fx+IOCompletionThunk.UnhandledExceptionFrame(UInt32, UInt32, System.Threading.NativeOverlapped*)
   at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32, UInt32, System.Threading.NativeOverlapped*)
</Data>
  </EventData>
</Event>

If you see event logs like these, it doesn’t definitely mean that IntelliTrace is causing the problem, but if you have IntelliTrace enabled, it is pretty likely that it is.

To determine for sure that IntelliTrace is the problem, you would need to capture a dump of the Worker Role process (WaWorkerHost.exe) by remoting into the instance and attaching a debugger to the process. If you look at the dump with Windbg or some other dump analysis tool, you want to look for the following exception:

Exception object: 0000000004acefc8
Exception type:   System.Runtime.CallbackException
Message:          Async Callback threw an exception.
InnerException:   System.InvalidProgramException, Use !PrintException 0000000004ad8f68 to see more.
StackTrace (generated):
<none>
StackTraceString: <none>
HResult: 80131501
0:018> !pe 0000000004ad8f68 
Exception object: 0000000004ad8f68
Exception type:   System.InvalidProgramException
Message:          Common Language Runtime detected an invalid program.
InnerException:   <none>
StackTrace (generated):
<none>
StackTraceString: <none>
HResult: 8013153a
====================================================================
0:106> !pe 00000000044ec790
Exception object: 00000000044ec790
Exception type:   System.InvalidProgramException
Message:          Common Language Runtime detected an invalid program.
InnerException:   <none>
StackTrace (generated):
    SP               IP               Function
    000000002CF1E600 0000000000000000 System_ServiceModel!System.ServiceModel.Dispatcher.ErrorBehavior.HandleErrorCommon(System.Exception, System.ServiceModel.Dispatcher.ErrorHandlerFaultInfo ByRef)+0x1
    000000002CF1E6D0 000007FF00F6B837 System_ServiceModel!System.ServiceModel.Dispatcher.ChannelDispatcher.HandleError(System.Exception, System.ServiceModel.Dispatcher.ErrorHandlerFaultInfo ByRef)+0xa7
    000000002CF1E730 000007FF00F6B650 System_ServiceModel!System.ServiceModel.Dispatcher.ChannelHandler.HandleError(System.Exception)+0x30
    000000002CF1E780 000007FF00E76AB2 System_ServiceModel!System.ServiceModel.Dispatcher.ChannelHandler.OpenAndEnsurePump()+0xc2
    000000002CF1E7E0 000007FF00E58184 System_Runtime_DurableInstancing!System.Runtime.IOThreadScheduler+ScheduledOverlapped.IOCallback(UInt32, UInt32, System.Threading.NativeOverlapped*)+0xf4
    000000002CF1E860 000007FF00E58035 System_Runtime_DurableInstancing!System.Runtime.Fx+IOCompletionThunk.UnhandledExceptionFrame(UInt32, UInt32, System.Threading.NativeOverlapped*)+0x115
    000000002CF1E8C0 000007FF009DC35B mscorlib!System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32, UInt32, System.Threading.NativeOverlapped*)+0x9b

StackTraceString: <none>

Note, this was shown using psscor4 and running !dumpallexceptions and then !printexception on the inner exception.

Solution

To resolve this, you need to redeploy your package to Azure and disable IntelliTrace.

Note

This problem was first posted on the MSDN forums.

Unhandled exception has occurred while running in Azure

ASP.NET Debugging — Thu, 22 Mar 2012 19:48:51 GMT

Windows Azure, just like any other IIS website can crash if an unhandled exception occurs. One way that this can happen is if you are calling an Async function call and in the function that is called on completion, you throw an exception.

In this situation, you will see something in the Application event log that looks like this:
Note: you may not see both of these errors but either or both of them point to the same problem.

The way to resolve this issue is to either wrap the code inside a Try/Catch block and catch the exception or see what is causing the exception and fix that bug. But if a block of code can throw an exception, it is always good to wrap it so that it can’t cause the entire process to crash.

The process crashing is something that started with .NET 2.0. You can read this KB article to get more information about this and how to make it run without crashing. There is also some more information on this on MSDN.

Azure deployment stuck Preparing node

ASP.NET Debugging — Mon, 27 Feb 2012 15:34:47 GMT

Problem

We recently had a case where a role was stuck in this state. So on the portal, the deployment line said “Initializing” and the role says “Preparing Node” and it never moves past this. We cannot remote in using RDP or anything else to see what is happening with the deployment. The error looks like:

Turns out one problem that can cause this is if you are using Unicode file names. During the packaging and preparation of the files, we urlencode the names so that they can be stored in a compressed format. If the encoded file names become longer then 260 bytes, then the compression tools fail to unzip the package correctly and you will be left in a state like this when trying to deploy.

Workaround

There are a couple of things you can do here to fix this problem.

Don’t use Unicode characters in file names.
Shorten the file names so they get until the 260 byte limit.

Using either of these methods will allow you to deploy successfully to Azure.

Using the Azure Management APIs from Linux

ASP.NET Debugging — Wed, 08 Feb 2012 21:22:52 GMT

If you want to use the Azure Management APIs from Linux, there are a few things you need to do so that it will work correctly. If you are getting a problem when you try to connect where it looks like the Azure side is just closing the connection, there are a few things that could be the problem.

There are the standard things that you need to make sure you do:

Make sure the certificate is at least 2048 bits
Make sure the certificate is uploaded and listed in the Azure portal under the management certificates

But assuming those things are all correct, you also need to make sure you use the SSL_CTX_set_mode function to set the following OpenSSL options:

SSL_MODE_AUTO_RETRY
SSL_ENABLE_PARTIAL_WRITE

That should allow you to connect to the management APIs.

You can also take a look at this forum post to see how to get curl to connect. This can be really helpful as curl has all of the source code so you can use that to see how to connect.

For more information on how to do this kind of thing from windows, take a look at this MSDN article.

Azure Storage Analytics

ASP.NET Debugging — Tue, 08 Nov 2011 21:08:49 GMT

Now that we have released the Windows Azure Storage Analytics, there are some useful tools to look at the data. If you want to write code to do this, you can check out this post for some sample code. You can also use Avkash's blog post to look at blob storage analytics using CloudBerry. If you want to do something similar with the other storage types (Queues and Tables) you can use a couple different tools to enable logging.

Cerebrata has a Storage Analytics Configuration utility that allows you to configure all of the settings or you can use the sample code posted by Steve Marx here to do this either from the website he has running or from your own web site that you build yourself using the source he provides.

Once you have the logging enabled, you then just wait for the logs to be propagated to blob storage and then you can look at them. For blob storage, you can use CloudBerry's nice UI to see all of the entries. For the other types, you have to use a tool to browse to the folder where they exist. One way is using the CloudBerry tool and connecting to your blob storage and typing in a custom path of just "$logs". You will then get something like the following:

From here you can browse into the subfolders for each of them and will end up seeing a log files, see this page for information about the folder structure. if you open that you will see the traffic coming into or out of the storage account. You can look at the documentation for Storage Analytics to see the format of the log files.

For metric data, there are tables created that you can look at. You can look at the metric files here for the format of the tables. You can use the Cerebrata Cloud Storage Studio to view these tables. They have a 30-day trial available or you can purchase it. Hopefully other tools will support these tables soon as well. You can read more about the metrics here.

Common items that use storage that you may not know about include:

IntelliTrace
Azure Diagnostics

These can be seen using this tool and if enabled, disabled if you aren't developing/debugging your Azure application.

Now Available: Psscor4 – Debugger Extension for .NET 4.0

ASP.NET Debugging — Thu, 28 Apr 2011 13:24:36 GMT

I am very happy to announce that Psscor4 is now available for download. You can download it from:

Psscor4 Managed-Code Debugging Extension for WinDbg

This should have the same functionality as Psscor2 does but it works against the .NET 4.0 Framework. Please let me know if you run into any problems downloading or using this extension. I would also love to know if you have any feature requests for it.

Help with Windows Azure role stuck in Initializing/Busy/Stopped state

ASP.NET Debugging — Fri, 25 Feb 2011 16:19:25 GMT

I have seen a number of issues where the Windows Azure role is stuck when you deploy it and you can’t get it started. There are a few great posts about this problem at:

One of the problems outlined here shows up because an exception is thrown in the OnStart function inside the WebRole.cs file in your Windows Azure WebRole. If an exception happens here, it becomes an unhandled exception because there is no try/catch and so the process that it is running in will be shut down. There is a great description of this at CLR Inside Out- Unhandled Exception Processing In The CLR.

So one way to help this situation is to add a try/catch inside the OnStart function. Below is such an example but I took it a step further and added code in the catch that will log the exception in the Event Log. That way we can see what is happening and investigate the problem.

Note: If the exception is caused by the Diagnostics code, you can’t use that to get the event log data, but you would be able to remote into the machine and look at the event log on the machine. The steps for that are here.

Here is what that function would look like:

        1: public override bool OnStart()

       2: {

       3:     try

       4:     {

       5:         // For information on handling configuration changes

       6:         // see the MSDN topic at http://go.microsoft.com/fwlink/?LinkId=166357.

       7:  

       8:     }

       9:     catch (Exception e)

    {

        #region "Handle Exception"

        System.Text.StringBuilder message = new System.Text.StringBuilder("\r\n\r\nException Occurred:\r\n\r\nappId=");

  

        String appId = (string)AppDomain.CurrentDomain.GetData(".appId");

        if (appId != null)

            message.Append(appId);

  

        message.AppendFormat("\r\n\r\ntype={0}\r\n\r\nmessage={1}\r\n\r\nstack=\r\n{2}\r\n\r\n",

            e.GetType().FullName,

            e.Message,

            e.StackTrace);

  

        string webenginePath = System.IO.Path.Combine(System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory(), "webengine.dll");

  

        if (!System.IO.File.Exists(webenginePath))

        {

            throw new Exception(String.Format(System.Globalization.CultureInfo.InvariantCulture,

                "Failed to locate webengine.dll at '{0}'. This module requires .NET Framework.",

                webenginePath));

        }

  

        System.Diagnostics.FileVersionInfo ver = System.Diagnostics.FileVersionInfo.GetVersionInfo(webenginePath);

        string _sourceName = string.Format(System.Globalization.CultureInfo.InvariantCulture, "ASP.NET {0}.{1}.{2}.0",

            ver.FileMajorPart, ver.FileMinorPart, ver.FileBuildPart);

  

        if (!System.Diagnostics.EventLog.SourceExists(_sourceName))

        {

            throw new Exception(String.Format(System.Globalization.CultureInfo.InvariantCulture,

                "There is no EventLog source named '{0}'. This module requires .NET Framework.",

                _sourceName));

        }

  

        System.Diagnostics.EventLog Log = new System.Diagnostics.EventLog();

        Log.Source = _sourceName;

        Log.WriteEntry(message.ToString(), System.Diagnostics.EventLogEntryType.Error);

        #endregion

    }

  

    return base.OnStart();

}

I added a region so you can minimize the catch code and just focus on your code inside the try. Hope this helps people to be able to handle problems in this function better and not have it keep the Role from starting up.

One last thing, I put this under the ASP.NET Source in the Event Log. So that is what you would look for in regards to entries. You can change this to something else, but keep in mind that if you add your own event source, the process can’t use it until it is restarted. There is an example doing that here. This is the same code that is shown in Unhandled exceptions cause ASP.NET-based applications to unexpectedly quit in the .NET Framework 2.0.

Installing and using an HttpModule in Windows Azure

ASP.NET Debugging — Fri, 18 Feb 2011 19:14:00 GMT

Windows Azure has a lot of great things about it, but one of the difficulties is that you can’t administer your IIS very easily as you don’t have access to the machine. If you use the Windows Azure 1.3 SDK or later and enable RDP, you can change IIS settings but if the role has to be restarted for some reason, it will lose whatever changes you have made.

So this is where using the OnStart of the WebRole can really help a developer out. For this example, I am going to use the IIS Application Warm-Up module. This is a good example because it is a rather complicated module to install and use properly.

Here is how you go about getting this module running in Windows Azure.

Note: You must be using the Windows Azure 1.3 SDK and have your site running using Full IIS for this to work.

Download the IIS Application Warm-Up module on your local machine and install it. This will get you the actual module: %windir%\system32\inetsrv\appwarmup.dll.
Add the appwarmup.dll module above to your Visual Studio WebRole project. Add it to the root of the application and be sure under Properties you have Build Action set to Content and Copy to Output Directory set to Copy always.
Add a Reference in the WebRole project to %windir%\system32\inetsrv\Microsoft.Web.Administration.dll.
Under the Properties of the newly added reference, change Copy Local to True.

Open the WebRole.cs file in the WebRole project, Modify it with the following code:

            1: using System;

           2: using System.Collections.Generic;

           3: using System.Linq;

           4: using Microsoft.WindowsAzure;

           5: using Microsoft.WindowsAzure.Diagnostics;

           6: using Microsoft.WindowsAzure.ServiceRuntime;

           7: using Microsoft.Web.Administration;

           8:  

           9: namespace WebRole1

          10: {

          11:     public class WebRole : RoleEntryPoint

          12:     {

          13:         public override bool OnStart()

          14:         {

          15:             // For information on handling configuration changes

          16:             // see the MSDN topic at http://go.microsoft.com/fwlink/?LinkId=166357.

          17:  

          18:             try

          19:             {

          20:                 System.Diagnostics.Trace.WriteLine("OnStart");

          21:                 // Before we do anything else, we have to create the schema file and write it to disk

          22:                 string appwarmupSchemaLocation = System.IO.Path.Combine(Environment.GetEnvironmentVariable("windir") + @"\", @"system32\inetsrv\config\schema\appwarmup_schema.xml");

          23:                 if (!System.IO.File.Exists(appwarmupSchemaLocation))

          24:                 {

          25:                     string[] lines = {

          26:                         "<configSchema>",

          27:                         "    <sectionSchema name=\"system.webServer/httpWarmupGlobalSettings\">",

          28:                         "      <attribute name=\"httpWarmupEnabled\" type=\"bool\" defaultValue=\"true\" />",

          29:                         "    </sectionSchema>",

          30:                         "",

          31:                         "    <sectionSchema name=\"system.webServer/httpWarmup\">",

          32:                         "      <element name=\"userContext\">",

          33:                         "        <attribute name=\"authMode\" type=\"enum\" defaultValue=\"SetNull\" >",

          34:                         "          <enum name=\"SetNull\" value=\"0\" />",

          35:                         "          <enum name=\"SetUserOnly\" value=\"1\" />",

          36:                         "          <enum name=\"SetToken\" value=\"2\" />",

          37:                         "        </attribute>",

          38:                         "        <attribute name=\"authType\" type=\"string\" defaultValue=\"\" />",

          39:                         "        <attribute name=\"username\" type=\"string\" defaultValue=\"\" />",

          40:                         "        <attribute name=\"password\" type=\"string\" encrypted=\"true\" caseSensitive=\"true\" defaultValue=\"[enc:AesProvider::enc]\" />",

          41:                         "      </element>",

          42:                         "      <element name=\"requests\" >",

          43:                         "        <collection addElement=\"add\" clearElement=\"clear\" removeElement=\"remove\" mergeAppend=\"false\" >",

          44:                         "          <attribute name=\"requestUrl\" type=\"string\" required=\"true\" isUniqueKey=\"true\" />",

          45:                         "          <attribute name=\"allowedResponseCodes\" type=\"string\" defaultValue=\"200-399\" />",

          46:                         "          <attribute name=\"warmupContext\" type=\"string\" />",

          47:                         "          <attribute name=\"sendMode\" type=\"enum\" defaultValue=\"Asynchronous\" >",

          48:                         "            <enum name=\"Synchronous\" value=\"1\" />",

          49:                         "            <enum name=\"Asynchronous\" value=\"2\" />",

          50:                         "          </attribute>",

          51:                         "        </collection>",

          52:                         "      </element>",

          53:                         "    </sectionSchema>",

          54:                         "",

          55:                         "</configSchema>"};

          56:  

          57:                     System.IO.File.WriteAllLines(appwarmupSchemaLocation, lines);

          58:                 }

          59:  

          60:                 // Create an instance of our ServerManager

          61:                 ServerManager iisManagerFirst = new ServerManager();

          62:  

          63:                 // Get the applicationHost.config file

          64:                 Configuration appHostConfigFirst = iisManagerFirst.GetApplicationHostConfiguration();

          65:  

          66:                 // Create a Section Definition for our new settings under <system.webServer>

          67:                 SectionDefinition definition = RegisterSectionDefinition(appHostConfigFirst, "system.webServer/httpWarmupGlobalSettings");

          68:                 definition.OverrideModeDefault = "Deny";

          69:                 definition.AllowDefinition = "MachineToApplication";

          70:                 SectionDefinition definition2 = RegisterSectionDefinition(appHostConfigFirst, "system.webServer/httpWarmup");

          71:                 definition2.OverrideModeDefault = "Allow";

          72:                 definition2.AllowDefinition = "MachineToApplication";

          73:  

          74:                 // Write these new settings out to the file, this allows us to add them later, otherwise we will get an exception

          75:                 // because the section doesn't have a definition

          76:                 iisManagerFirst.CommitChanges();

          77:  

          78:                 // Get another instance of our ServerManager as the first one is committed so it is read-only

          79:                 ServerManager iisManager = new ServerManager();

          80:  

          81:                 // Find our application

          82:                 Application app = iisManager.Sites[RoleEnvironment.CurrentRoleInstance.Id + "_Web"].Applications[0];

          83:  

          84:                 // Get the applicationHost.config file

          85:                 Configuration appHostConfig = iisManager.GetApplicationHostConfiguration();

          86:  

          87:                 // Get the appPool for this application

          88:                 ConfigurationSection appPoolSection = appHostConfig.GetSection("system.applicationHost/applicationPools");

          89:                 ConfigurationElementCollection poolCollection = appPoolSection.GetCollection();

          90:                 ConfigurationElement appPoolElement = FindElement(poolCollection, "add", "name", app.ApplicationPoolName);

          91:  

          92:                 if (appPoolElement == null) throw new InvalidOperationException("App Pool element not found!");

          93:  

          94:                 // Set the attribute startMode="AlwaysRunning"

          95:                 appPoolElement.SetAttributeValue("startMode", "AlwaysRunning");

          96:  

          97:                 // Add AppWarmupModule to the globalModules section of system.webServer, only if it doesn't already exist

          98:                 ConfigurationSection globalSection = appHostConfig.GetSection("system.webServer/globalModules");

          99:                 ConfigurationElementCollection globalCollection = globalSection.GetCollection();

         100:                 ConfigurationElement globalElement = FindElement(globalCollection, "add", "name", "AppWarmupModule");

         101:  

         102:                 if (globalElement == null)

         103:                 {

         104:                     ConfigurationElement globalElement2 = globalCollection.CreateElement("add");

         105:                     globalElement2.SetAttributeValue("name", "AppWarmupModule");

         106:                     string appwarmupLocation = System.IO.Path.Combine(Environment.GetEnvironmentVariable("RoleRoot") + @"\", @"approot\appwarmup.dll");

         107:                     System.Diagnostics.Trace.WriteLine("Location: " + appwarmupLocation);

         108:                     globalElement2.SetAttributeValue("image", appwarmupLocation);

         109:                     globalCollection.Add(globalElement2);

         110:                 }

         111:  

         112:                 // Add AppWarmupModule to the modules section of system.webServer, only if it doesn't already exist

         113:                 // This is adding to the <location path="" ...> section, which is why we have a second parameter

         114:                 ConfigurationSection modulesSection = appHostConfig.GetSection("system.webServer/modules", "");

         115:                 ConfigurationElementCollection modulesCollection = modulesSection.GetCollection();

         116:                 ConfigurationElement modulesElement = FindElement(modulesCollection, "add", "name", "AppWarmupModule");

         117:  

         118:                 if (modulesElement == null)

         119:                 {

         120:                     System.Diagnostics.Trace.WriteLine("Add AppWarmupModule");

         121:                     ConfigurationElement modulesElement2 = modulesCollection.CreateElement("add");

         122:                     modulesElement2.SetAttributeValue("name", "AppWarmupModule");

         123:                     modulesCollection.Add(modulesElement2);

         124:                 }

         125:  

         126:                 // Add httpWarmupEnabled to the new httpWarmupGlobalSettings section of system.webServer

         127:                 // This is adding to the <location path="OurRoleId" ...> section, which is why we have a second parameter

         128:                 ConfigurationSection warmupSection = appHostConfig.GetSection("system.webServer/httpWarmupGlobalSettings", RoleEnvironment.CurrentRoleInstance.Id + "_Web");

         129:                 System.Diagnostics.Trace.WriteLine("Add httpWarmupEnabled");

         130:                 warmupSection.SetAttributeValue("httpWarmupEnabled", "true");

         131:  

         132:                 // Add our requests to the new httpWarmup section of system.webServer

         133:                 // This is adding to the <location path="OurRoleId" ...> section, which is why we have a second parameter

         134:                 ConfigurationSection warmupSection2 = appHostConfig.GetSection("system.webServer/httpWarmup", RoleEnvironment.CurrentRoleInstance.Id + "_Web");

         135:                 ConfigurationElement requestsElement = warmupSection2.GetChildElement("requests");

         136:                 ConfigurationElementCollection warmupCollection = requestsElement.GetCollection();

         137:  

         138:                 // TODO: change <Warmup File.aspx> to the correct filename we want to browse to warm up the application

         139:                 ConfigurationElement warmupElement = FindElement(warmupCollection, "add", "requestUrl", "<Warmup File.aspx>");

         140:  

         141:                 if (warmupElement == null)

         142:                 {

         143:                     ConfigurationElement warmupElement2 = warmupCollection.CreateElement("add");

         144:  

         145:                     // TODO: change <Warmup File.aspx> to the correct filename we want to browse to warm up the application

         146:                     warmupElement2.SetAttributeValue("requestUrl", "<Warmup File.aspx>");

         147:                     warmupElement2.SetAttributeValue("allowedResponseCodes", "200-399");

         148:                     warmupElement2.SetAttributeValue("warmupContext", "This is a warmup request");

         149:                     warmupElement2.SetAttributeValue("sendMode", "Asynchronous");

         150:                     warmupCollection.Add(warmupElement2);

         151:                 }

         152:  

         153:                 System.Diagnostics.Trace.WriteLine("CommitChanges");

         154:                 iisManager.CommitChanges();

         155:             }

         156:             catch (Exception e)

         157:             {

         158:                 System.Diagnostics.Trace.WriteLine(e.ToString());

         159:             }

         160:  

         161:             return base.OnStart();

         162:         }

         163:  

         164:         /// <summary>

         165:         /// This function will create a SectionDefinition given a configuration and a path, the path can have /'s in it

         166:         /// </summary>

         167:         /// <param name="config"></param>

         168:         /// <param name="sectionPath"></param>

         169:         /// <returns></returns>

         170:         private SectionDefinition RegisterSectionDefinition(Configuration config, string sectionPath)

         171:         {

         172:             string[] paths = sectionPath.Split('/');

         173:  

         174:             SectionGroup group = config.RootSectionGroup;

         175:             for (int i = 0; i < paths.Length - 1; i++)

         176:             {

         177:                 SectionGroup newGroup = group.SectionGroups[paths[i]];

         178:                 if (newGroup == null)

         179:                 {

         180:                     System.Diagnostics.Trace.WriteLine("Creating: " + paths[i]);

         181:                     newGroup = group.SectionGroups.Add(paths[i]);

         182:                 }

         183:  

         184:                 group = newGroup;

         185:             }

         186:  

         187:             SectionDefinition section = group.Sections[paths[paths.Length - 1]];

         188:             if (section == null)

         189:             {

         190:                 System.Diagnostics.Trace.WriteLine("Creating: " + paths[paths.Length - 1]);

         191:                 section = group.Sections.Add(paths[paths.Length - 1]);

         192:             }

         193:  

         194:             return section;

         195:         }

         196:  

         197:         /// <summary>

         198:         /// This function will look for an element with the given name/value pairs and the given elementTagName

         199:         /// </summary>

         200:         /// <param name="collection"></param>

         201:         /// <param name="elementTagName"></param>

         202:         /// <param name="keyValues"></param>

         203:         /// <returns></returns>

         204:         private ConfigurationElement FindElement(ConfigurationElementCollection collection, string elementTagName, params string[] keyValues)

         205:         {

         206:             foreach (ConfigurationElement element in collection)

         207:             {

         208:                 if (String.Equals(element.ElementTagName, elementTagName, StringComparison.OrdinalIgnoreCase))

         209:                 {

         210:                     bool matches = true;

         211:                     for (int i = 0; i < keyValues.Length; i += 2)

         212:                     {

         213:                         object o = element.GetAttributeValue(keyValues[i]);

         214:                         string value = null;

         215:                         if (o != null)

         216:                             value = o.ToString();

         217:  

         218:                         if (!String.Equals(value, keyValues[i + 1], StringComparison.OrdinalIgnoreCase))

         219:                         {

         220:                             matches = false;

         221:                             break;

         222:                         }

         223:                     }

         224:  

         225:                     if (matches)

         226:                         return element;

         227:                 }

         228:             }

         229:  

         230:             return null;

         231:         }

         232:     }

         233: }

Update (2/23/2011): I have made a few updates above based on some testing.

Note: On lines 82, 128, 134 this code uses “_Web” as part of the role name. If you change the name in the ServiceDefinition.csdef file (<Site name=”Web”>) then you will need to adjust that code accordingly. Also, if you have multiple sites, all 3 of these locations (adding the values there) will need to be done for each site you want to warm up.

In the OnStart function that we just added above, change the two instances of <Warmup File.aspx> (these are on lines 139 and 146 in the above code) to point to the file you want to have browsed for warming up your application.

Note: You can add additional requests and more advanced things to this, check out the Advanced Scenarios section of Getting Started with the IIS 7.5 Application Warm-Up Module for more information.
Open the ServiceConfiguration.cscfg file and ensure the osFamily attribute of the ServiceConfiguration element is set to “2”. This will ensure you are using Windows Server 2008 R2 which has IIS 7.5 which is required for the IIS Application Warm-Up module.
Open the ServiceDefinition.csdef file and add the following entry inside the <WebRole > section:
```
<Runtime executionContext="elevated" />
```
Build your application and upload it to Windows Azure.

Once you have done these steps, your application should be running now using the Warm-Up module. So the first request to a page, once the site is ready to run, should be just as fast as any other request.

There is another alternative, instead of doing all of this in the OnStart of your WebRole and forcing your Role to run elevated, you can also create a StartupTask to do the same thing and have it run elevated. That would basically entail doing this same code in your own exe and then running the StartupTask. There is a good discussion of them at Azure Startup Tasks and Powershell- Lessons Learned - Jim O'Neil

WCF RIA 4.0 requires an Entity Model that includes Foreign Key Information

ASP.NET Debugging — Mon, 26 Jul 2010 18:54:56 GMT

If you try to build a WCF RIA Application and the Entity Model (EM) doesn’t include foreign key information you will get an error like:

Unable to retrieve association information for association ‘MyModel.MyAssociation’. Only models that include foreign key information are supported. See Entity Framework documentation for details on creating models that include foreign key information.

There are three ways to get around this error.

If you are creating the model from a database, be sure to check the “Include foreign key columns in the model” setting when generating the model from the database.
If you are creating a model and will generate the database from the model and you are not creating a 1 to many association, then you have to double click on the association in the model. This will bring up the Referential Constraint editor and allow you to add the foreign key details.
If you are creating a model and will generate the database from the model and you are creating a 1 to many association, you can check the “Add foreign key properties to the ‘MyObject’ Entity” setting when generating the association between the tables.

You can read all of the breaking changes in 4.0 in this document.

Some of this information is also talked about here.

New Psscor2 commands – Dealing with Dates and Times

ASP.NET Debugging — Thu, 22 Apr 2010 19:49:43 GMT

If you have ever tried to look at a System.DateTime or System.TimeSpan object in a debugger, you know how difficult it is to see what the value is. For example, this is what a System.DateTime object looks like:

0:017> !do 0x040f59b8 
Name: System.DateTime
MethodTable: 60809f0c
EEClass: 605e1fd8
Size: 16(0x10) bytes
GC Generation: 2
 (C:\Windows\assembly\GAC_32\mscorlib\2.0.0.0__b77a5c561934e089\mscorlib.dll)
Fields:
      MT    Field   Offset                 Type VT     Attr    Value Name
6080ab9c  40000f4        4        System.UInt64  1 instance 633739266270770000 dateData
6082aa5c  40000f0       30       System.Int32[]  0   shared   static DaysToMonth365
    >> Domain:Value  0097ce58:03d6cad0 <<
6082aa5c  40000f1       34       System.Int32[]  0   shared   static DaysToMonth366
    >> Domain:Value  0097ce58:03d6cb10 <<
60809f0c  40000f2       28      System.DateTime  1   shared   static MinValue
    >> Domain:Value  0097ce58:03d6cab0 <<
60809f0c  40000f3       2c      System.DateTime  1   shared   static MaxValue
    >> Domain:Value  0097ce58:03d6cac0 <<

Figuring out what time this is can be very difficult.

This is where some of the new commands in psscor2 can really help you out. There are a few different commands so let me explain them each so you can use them when you need to.

!PrintDateTime

The first one is !PrintDateTime. This command takes a System.DateTime object or a System.TimeSpan object and prints it out as a date. For example:

0:017> !printdatetime 0x0420e658 
As a TimeSpan: 733494.12:30:27.0770000
As a DateTime: 03/29/2009 12:30:27

It will always print out both as there is no way to tell if the object is really a System.DateTime or a System.TimeSpan as both are stored in a System.DateTime object.

So in this example, it is a DateTime and we call tell that because the DateTime is a valid time. For a TimeSpan, the output will look something like:

0:017> !printdatetime 0x040f59b8 
As a TimeSpan: 25.00:00:00
As a DateTime: 01/01/1753 00:00:00

!ConvertTicksToDate (ctd)

This command works against the actual ticks (dateData field of the DateTime object). It works the same way, but sometimes you will have objects that store ticks so it is nice to be able to run this directly against them. The output looks the same:

0:017> !ctd 633739266270770000
As a TimeSpan: 733494.12:30:27.0770000
As a DateTime: 03/29/2009 12:30:27

!ConvertVTDateToDate (cvtdd)

This command is useful when the DateTime you are looking at is a Value Type. In this case, if you try to use the other commands, you will get errors because there is no Method Table for the object. You can see here that the _startTime has a 1 set for the VT column so it is a value type object:

0:000> !do 0x18346ff4 
Name: System.Web.Hosting.ISAPIWorkerRequestInProcForIIS6
MethodTable: 68a1f7c8
EEClass: 68a1f748
Size: 252(0xfc) bytes
GC Generation: 0
 (C:\WINNT\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll)
Fields:
      MT    Field   Offset                 Type VT     Attr    Value Name
79105ef0  4001294        4      System.DateTime  1 instance 18346ff8 _startTime

If you !do this, you will get:

0:000> !do 18346ff8 
<Note: this object has an invalid CLASS field>
Invalid object

!PrintDateTime will show the correct output, of if you use !cvtdd:

0:000> !cvtdd 18346ff8 
As a TimeSpan: 6070081.06:18:02.6363604
As a DateTime: 06/20/2006 16:53:59

Let me know what you guys think of these new commands.

New Psscor2 commands – ClrStack showing source and line numbers

ASP.NET Debugging — Mon, 12 Apr 2010 20:24:28 GMT

Continuing on from my previous post about DumpAllExceptions, here is another new update that comes with psscor2. When you run !clrstack, you will now see the source and line information for the functions that are displayed. This can be really helpful when trying to track down where a problem is and what path through your code this execution has taken.

You don’t have to do anything to make this output display, it will automatically at the end of the line.

The output will look something like:

02b9ef98 687db33a MyFile.DoWork(System.Web.HttpContext) c:\MyFile.cs:3710

So if you look at that output, it has c:\MyFile.cs as the name of the file and 3710 as the line number.

Hope everyone finds this information useful. If you need to get psscor2, take a look at this post:
New debugger extension for .NET, Psscor2, released

New Psscor2 commands – DumpAllExceptions

ASP.NET Debugging — Tue, 30 Mar 2010 22:35:50 GMT

There have been a few places where you can see this command run, but I wanted to talk about it here officially. This command is used to display all of the exceptions that are currently in the managed heap. One interesting thing is that this function actually looks at what class the object derives from and if it derives from System.Exception, then it will show up in the list. So you can have your own custom exceptions shown here regardless of what naming mechanism you use for your class.

There is some helpful information about the output from this command here: ASP.NET Debugging - ASP.NET Tips- DumpAllExceptions, namely that if you run it twice, you may see different callstacks from the various exceptions.

Here is the documentation straight from !help:

0:017> !help dumpallexceptions
-------------------------------------------------------------------------------
!DumpAllExceptions [-v]

!DumpAllExceptions will go through the entire managed heap and find any objects that are derived 
from System.Exception.  It will print out the inner exceptions and other common items of an 
exception.  This will only print out one exception of each type and give you the count of those 
type of exceptions.

The -v parameter will print out each exception individually.

As you can see, one key aspect to note is that this command will group exceptions together, as seen here:

0:017> !dae
Going to dump the .NET Exceptions found in the heap.
Loading the heap objects into our cache.
Number of exceptions of this type:        1
Exception MethodTable: 60828c04
Exception object: 03d510b4
Exception type: System.ExecutionEngineException
Message: <none>
InnerException: <none>
StackTrace (generated):
<none>
StackTraceString: <none>
HResult: 80131506
The current thread is unmanaged
-----------------

Number of exceptions of this type:        1
Exception MethodTable: 60828b74
Exception object: 03d5106c
Exception type: System.StackOverflowException
Message: <none>
InnerException: <none>
StackTrace (generated):
<none>
StackTraceString: <none>
HResult: 800703e9
The current thread is unmanaged
-----------------

Number of exceptions of this type:        1
Exception MethodTable: 60828ae4
Exception object: 03d51024
Exception type: System.OutOfMemoryException
Message: <none>
InnerException: <none>
StackTrace (generated):
<none>
StackTraceString: <none>
HResult: 8007000e
The current thread is unmanaged
-----------------

Number of exceptions of this type:        2
Exception MethodTable: 60828c94
Exception object: 03d510fc
Exception type: System.Threading.ThreadAbortException
Message: <none>
InnerException: <none>
StackTrace (generated):
<none>
StackTraceString: <none>
HResult: 80131530
The current thread is unmanaged
-----------------

Total 5 exceptions

So if you want to see all the exceptions of a particular type, use the -v switch. One more important thing to keep in mind, this will only print out these sections of an exception (the ones you see above). So if you want to see something particular to an exception, you need to dump it out using !dumpobj.

New debugger extension for .NET, Psscor2, released

ASP.NET Debugging — Mon, 29 Mar 2010 17:37:00 GMT

*UPDATE* The download is now 32-bit !

I wanted to be the first to inform everyone that there is a major update to the debugger extension story for .NET. Psscor2 has been released! This is a superset of the SOS.dll that ships with the framework.

This extension has a lot of advantages over SOS if you are trying to troubleshoot problems, especially if they are caused by ASP.NET. All of the functionality that has been talked about on this blog for the SOS that comes with the debugger is now available for .NET Framework 2.0, 3.0, and 3.5.

This one extension will troubleshoot all of those versions.

I will be getting into the new commands and talking more about this in the coming weeks. But I wanted to let everyone know and have you all go download the extension.

The download contains a version for x86, amd64, and ia64. Just like SOS, please be sure the debugger and psscor2 match the architecture of the process you want to troubleshoot.

This extension is being released AS IS. So there is no support for it. But having said that, if you have an issue or problem, please post it here on my blog and I will try to look into it.

Go download Psscor2 and give it a try. Happy debugging!

Profilers and ASP.NET

ASP.NET Debugging — Fri, 26 Feb 2010 21:49:24 GMT

There are a lot of different ways to troubleshoot ASP.NET issues. I have gone over most of the things you can do with a dump that has been captured from the process. But there is another way to get useful information out of a process and that is by using a profiler.

There are a number of profilers that are available for .NET applications. Some of the more popular ones include (most come from Brads post and there is a good list here as well):

Traditional Performance and/or Memory Profilers

AutomatedQA AQTime: http://www.automatedqa.com/products/aqtime/index.asp (evaluation version available)
Borland Optimizeit: http://www.borland.com/opt_profiler/ (evaluation version available)
Compuware DevPartner: http://www.compuware.com/products/devpartner/default.htm (evaluation version available)
Intel VTune: http://www.intel.com/software/products/vtune/index.htm (evaluation version available)
Rational PurifyPlus: http://www-306.ibm.com/software/awdtools/purifyplus/win/ (evaluation version available)
Red Gate ANTS Profiler: http://www.red-gate.com/code_profiling.htm (evaluation version available)
SciTech .NET Memory Profiler: http://memprofiler.com/ (evaluation version available)
GlowCode http://www.glowcode.com/summary.htm (evaluation version available)
NProf: http://code.google.com/p/nprof/
JetBrains .NET Profiler: http://confluence.jetbrains.net/display/NetProf/EAP
CLR Profiler: http://www.microsoft.com/downloads/details.aspx?FamilyId=86CE6052-D7F4-4AEB-9B7A-94635BEEBDDA&displaylang=en

Enterprise Health Monitors

AVICode Intercept Studio: http://www.avicode.com/content/products/InterceptStudio.asp
Identify AppSight: http://www.identify.com/solutions/solutions.html
Mercury (Various Products): http://www.mercury.com/us/solutions/net/
Tonic WebLens: http://www.tonic.com/products/weblens.php
CA Wily Introscope: http://www.ca.com/us/application-management.aspx

The drawback with any of these profilers is that it has to be enabled prior to the process starting up. So it is very difficult to use these to analyze a web server.

Note: SciTech has the following on their website (but I haven’t actually tested it out) - A wizard is also provided for connecting the profiler to already running processes, or to import memory dump files. This is especially useful when profiling problems in a production application.

With .NET 4.0, this will change as profilers are allowed to attach to a running process. This will make profiling much better when dealing with ASP.NET. Check out David’s blog for more info on that.

I have used some of these and have had my own experiences with them but I really want to hear what you guys think.

Some questions I have for you guys in regards to profilers:

Do you use a profiler against your code?
Which profiler(s) have you used?
How much success do you have with it?
Are you thinking of using a profiler to help track down any issues?
What features do you think would be really useful for a profiler to have?
What drawbacks keeps you from using a profiler?
Would you consider running a type of profiler against your application in development if it helped you to get a better idea of performance or potential issues with your code?

Intermittently the Server sends back 0 byte WebResource.axd and ScriptResource.axd files

ASP.NET Debugging — Tue, 16 Feb 2010 21:14:05 GMT

Recently had this problem with a customer. The full details and the solution follow.

Problem

The customer had an AJAX website where intermittently he sees that the webresource.axd and scriptresource.axd come down from the server as 0 bytes and therefore the page is incorrect. When the issue happens, it keeps happening until the customer does an IIS reset or reloads the AppDoman by making some changes in the web.config.

The customer can repro the issue faster if he has HTTP Compression turned on but the issue happens even without compression. In the Fiddler, netmon or FREB tracing, we see that the server sends a HTTP 200 OK response and only the response headers with no body.

Cause

There are a few things at work here. First there is a known bug in IE8 that is part of the problem. We have known the IE8 could send corrupted requests to the server. These bad requests will cause runtime exceptions thrown by the corresponding handlers. The customer has implemented Application_Error method in global.asax to handle these errors by calling Server.Transfer to show a common custom error page (“~/HandleExceptions.aspx”) to end users. However, another exception was thrown from this error handling page. Here is the exception and stack from one of the dumps below.

0:004> !pe 000000017f936130
Exception object: 000000017f936130
Exception type: System.Web.HttpRequestValidationException
Message: A potentially dangerous Request.RawUrl value was detected from the client (="...case();});</script><div%20id=%...").
InnerException: <none>
StackTrace (generated):
    SP               IP               Function
    00000000063FE030 000007FF0054698F system_web!System.Web.HttpRequest.ValidateString(System.String, System.String, System.String)+0x18f
    00000000063FE090 000007FF0055F969 system_web!System.Web.HttpRequest.get_RawUrl()+0xb9
    00000000063FE0D0 000007FF00316F99 mysite_web!MySite.Web.Code.Page.OnPreRender(System.EventArgs)+0x59
    00000000063FE120 000007FF0055F734 system_web!System.Web.UI.Control.PreRenderRecursiveInternal()+0x94
    00000000063FE170 000007FF0054571B system_web!System.Web.UI.Page.ProcessRequestMain(Boolean, Boolean)+0x13db
    00000000063FE240 000007FF00543467 system_web!System.Web.UI.Page.ProcessRequest(Boolean, Boolean)+0x187
    00000000063FE2A0 000007FF0054324C system_web!System.Web.UI.Page.ProcessRequest()+0x5c
    00000000063FE300 000007FF00401DA0 system_web!System.Web.UI.Page.ProcessRequest(System.Web.HttpContext)+0xf0
    00000000063FE350 000007FF007BFA3A app_web_ohaik_5b!ASP.handleexceptions_aspx.ProcessRequest(System.Web.HttpContext)+0xa

The exception was thrown because the original url contains some javascript, which is not a “safe” string in ASP.NET perspective. Normally, the Server.Transfer will end the response for any further processing if no errors, but this exception interrupted the execution of Server.Transfer, which skipped the call to Response.End() and makes the server continue to process upcoming notifications/events. Even more unfortunately, the customer’s error handling page has an OutputCache directive, which makes the request respond to the UpdateRequestCache notification and put the half-way done response produced by the error handling page into the output cache for keys like WebResource.axd and ScriptResource.axd. Once these bad cache entries are put into output cache, the server cannot correctly respond for any new requests to WebResource.axd or ScriptResource.axd even with correct parameters.

Resolution

There are a few recommendations to resolve this issue:

The customer should remove the OutputCache directive from the HandleExceptions.aspx page. I can see the customer want the error page cached instead of rendering it every time. However, since this page is invoked by Server.Transfer, which calls Response.End anyway. So this page will never be cached if everything works fine. Only when something went wrong, the call to Response.End would be skipped and the bad response would be put into cache.
The above HttpRequestValidationException was thrown because url validation is on by default. The customer could add ValidateRequest=”false” in the Page directive of the HandleExceptions.aspx page. This will make the error page show correctly for these corrupted *.axd requests.

Azure: There is not enough space on the disk

ASP.NET Debugging — Fri, 04 Dec 2009 16:55:14 GMT

Problem

There may be some times where you will see this message when developing an application for Windows Azure. The message will look like:

There is not enough space on the disk.
Description: An unhandled exception occurred during the execution 
of the current web request. Please review the stack trace for more 
information about the error and where it originated in the code. 

Exception Details: System.IO.IOException: There is not enough 
space on the disk.


Source Error: 
An unhandled exception was generated during the execution of the 
current web request. Information regarding the origin and location 
of the exception can be identified using the exception stack trace 
below. 

Stack Trace: 
  
[IOException: There is not enough space on the disk.]
   System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) +10546789
   System.IO.FileStream.WriteCore(Byte[] buffer, Int32 offset, Int32 count) +10351324
   System.Web.TempFile.AddBytes(Byte[] data, Int32 offset, Int32 length) +26
   System.Web.HttpRawUploadedContent.AddBytes(Byte[] data, Int32 offset, Int32 length) +327
   System.Web.HttpRequest.GetEntireRawContent() +515
   System.Web.HttpRequest.GetMultipartContent() +72
   System.Web.HttpRequest.FillInFormCollection() +248
   System.Web.HttpRequest.get_Form() +79
   System.Web.HttpRequest.get_HasForm() +73
   System.Web.UI.Page.GetCollectionBasedOnMethod(Boolean dontReturnNull) +54
   System.Web.UI.Page.DeterminePostBackMode() +90
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +268

The typical situation where you will see this is if you are using the ASP.NET FileUpload control to let users upload files.

If the file they try to upload exceeds 100 MB, it will error with this message.

Resolution

There are a few ways that you can work around this issue. The best solution would be to use Silverlight to handle the upload instead of the ASP.NET FileUpload control. By using Silverlight, you can have the client directly upload the file to blob storage and reduce how many places the file gets copied.

There are also some 3rd party controls that you can use to do this as well.

More Information

The problem with the ASP.NET FileUpload control is that it writes the file to a temp folder during upload. The folder that is used in Windows Azure is limited to 100 MB so if you try to write something larger then that, it will fail.

I haven’t tested this, but if you have multiple users uploading data at the same time, you could see the same problem. For example, if 15 users all upload a 10 MB file at the same time, the temp folder will probably fill up and give the same error.

Note: there is a setting that you may be temped to use which is the tempDirectory attribute off the compilation element. If you try to set this to anything, it will cause your Web Role to not start up.

Updates to Windows Azure from PDC

ASP.NET Debugging — Mon, 30 Nov 2009 19:06:15 GMT

Wow there have been a lot of updates to the Windows Azure Platform that were announced at the PDC. I would love to hear from folks to let me know what they are most excited about. I was most impressed with the announcement of Dallas. I think that has the potential to change the way that we get information and consume it. It is great that companies like NASA can expose lots of information to people in a structured manner and allow the consumer to decide what they want to do with it.

I have been looking into the methods to debug applications in Windows Azure and hope to be able to talk about that very soon on this blog. So stay tuned for that and please let me know if you have any ideas of the types of data/information you would like to see.

Contest: What have you done with .NET?

ASP.NET Debugging — Thu, 05 Nov 2009 17:48:58 GMT

Do you develop applications using .NET? If so, head on over to this new contest at http://www.mydotnetstory.com and entry your story for a chance to win some really great prizes. What can you win? Well, if you are chosen by the judges, you could win a trip the the Galapagos Islands or a Smart Car or just cash! If you are one of the top 3 vote getters on the site, you will win an Internet Media Tablet. For more information on the prizes, check out the Contest site.

If you want to read about some of the powerful and “unexpected” .NET stories by REAL developers, please check out the campaign site.

Also, if you are planning on attending the PDC, check out the PDC Party at 8:00 pm in the VS / .NET Lounge Theater. You have a chance to win a Zune HD 32 GB by answering questions correctly there.

I hope to see a lot of really great applications discussed on there.

Good luck!

Impersonation, WCF, and making updates to a database

ASP.NET Debugging — Thu, 17 Sep 2009 22:14:59 GMT

I was troubleshooting a problem with WCF where the updates to a remote database were failing. The reason for the failure was found pretty quickly to be delegation.

For general impersonation questions in regards to WCF, there is lots of great information found here.

For my situation, the problem was that the ASP.NET application that was calling the WCF service was impersonating and I couldn’t enable delegation in my environment. So the connection to SQL failed. There are a number of ways to solve this problem, but some have more problems then others.

Fix #1

The easiest way is the add a User ID and Password to the web.config file. But then you have to worry about updating that if the password expires and also the security of having the password in the config file.

Note: You can add the password to the registry following KB329290

Fix #2

Another option would be to impersonate a given user on the network that has permission and use that when you are making the calls to the database. You can follow the “Impersonate a Specific User in Code” section of KB306158 for that. This also has the problem of passwords expiring and that the password is stored in code, but it isn’t in a config file anymore.

Fix #3

The one I ended up using was this one. In my case, the IIS Worker Process was already running under a network account that could assess the database. So I just needed a way to get rid of the impersonation that the process was running under, do the database work, and then impersonate again. The key was to do the following:

     WindowsImpersonationContext wic = null;

    try

    {

        wic = WindowsIdentity.Impersonate(IntPtr.Zero); // revert to self

        // Do database work here

    }

    finally

    {

        if (wic != null)

            wic.Undo(); // resume impersonating

    }

This will revert to self, let the database code run and then continue impersonating after that is done.

With this code, I don’t have to store any passwords in my code or config files. And everything will work correctly. The only drawback is that all database work is going through a single account and so on the database side, you can’t do auditing by users to see what they are doing. But in my application, I am already logging information into the database so there would be no need to have that kind of information.

Debugging .NET apps for .NET 4.0

ASP.NET Debugging — Wed, 02 Sep 2009 19:45:35 GMT

With Visual Studio 2010 and .NET 4.0 getting ready to be shipped sometime in the next year, I wanted to see what were peoples ideas for how to debug applications that were written with them. Are you happy in production with what you are currently doing? Do you use SOS.dll to troubleshoot problems?

SOS

The main place I am really interested in is production debugging. Is SOS a sufficient tool to get the data that you need? If you had another version of SOS for .NET 4.0, would you be happy with the features it has or would you want something more?

Debugger

I understand that using a typical debugger can be very difficult for people. If you don’t know what you are looking at, it can be very difficult to understand what is a problem and what is normal. It is also very difficult to see typical problems. For example, if you know your program is crashing due to running out of memory, what do you do to see what is taking up memory? How do you tell if it is fragmentation? What types of fragmentation are there that you would need to look for?

I wanted to see what the interest is in a different way of looking at the data, something more along the lines of DebugDiag.

Opinions

I’d love to hear your thoughts. Let me know!

Discounts on Microsoft Certification Exams

ASP.NET Debugging — Tue, 01 Sep 2009 21:41:34 GMT

In case anyone is interested in taking some Microsoft Exams, we have some discounts on them. Here is the announcement talking about the discounts:

Get up to 25 percent off select Microsoft Certification exams

In this tough economy, are you looking to get ahead? Do you want to stand out? Microsoft Certification can help you pursue a new career in IT, move from one job role to another, or become indispensible in your existing role. Microsoft Certifications are continually evaluated and updated to ensure their relevance in the marketplace. As a result, earning a certification not only helps you stay current on the latest developments in Microsoft technologies and platforms; it also enables you to demonstrate to employers your job skills.

To make it easier for you to get started, you can now take advantage of a new set of discounts that Microsoft is providing on select Microsoft Certification exams. Visit the website below to find out how to begin and to see whether the exam you’re interested in is 15%, 20% or 25% off. This offer is available worldwide while supplies last, and you have to register, schedule and purchase your discounted exam by December 31, 2009.

http://www.microsoft.com/learning/careeroffers

WCF, Silverlight, and SharePoint… Oh my!

ASP.NET Debugging — Mon, 31 Aug 2009 22:33:42 GMT

I was recently working on a project and needed to have Silverlight make a WCF call. That is pretty straight forward until you place the Silverlight code inside SharePoint and want it to call a WCF that is also inside SharePoint.

The first problem that I had to solve was getting Silverlight to be able to call the WCF correctly. Since in Visual Studio when you make the connection, it will have the local server for the path. Like http://localhost:95559/MyService.svc and for SharePoint I wanted it to point to the local server’s name and in the _layouts directory. Luckily I came across the following blog that helped with getting that to work: Silverlight ServiceReferences.ClientConfig Alternatives

The only change I had to make was to the BasicHttpBinding:

        1: BasicHttpBinding binding = new BasicHttpBinding(

       2:             Application.Current.Host.Source.Scheme.Equals("https", StringComparison.InvariantCultureIgnoreCase) 

       3:             ? BasicHttpSecurityMode.Transport : BasicHttpSecurityMode.TransportCredentialOnly);

Then I had to figure out how to get WCF hosted in SharePoint correctly. For that, I turned to this post: Hosting a WCF service in Windows Sharepoint Services v3.0

So I now had a httpModule that would handle the *.svc requests that start with a ~. That is important to make sure because you will get called again without the ~ so make sure you check for that before removing the first character. I also had Silverlight setup where it could call the SharePoint machine regardless of what Visual Studio wanted to do. I followed the “Dynamic Configuration” setup.

When I had this setup, I then got problems still. The only way I could see the problem was running something like Network Monitor or Web Development Helper. In there I saw a 500 error being returned from the server. I attached a debugger and saw that it was giving me this message:

Security settings for this service require ‘Anonymous’ Authentication but it is not enabled for the IIS application that hosts this service.

From this error, I realized that WCF uses anonymous by default. So I went into my web.config file and changed the binding to support Windows:

       1: <bindings>

       2:     <basicHttpBinding>

       3:         <binding name="MyBinding">

       4:             <security mode="TransportCredentialOnly">

       5:                 <transport clientCredentialType="Windows"/>

       6:             </security>

       7:         </binding>

       8:     </basicHttpBinding>

       9: </bindings>

Then you just add a bindingConfiguration=”MyBinding” on your service endpoint.

After I made that change, I ran it again and this time I got the following error:

Security settings for this service require Windows Authentication but it is not enabled for the IIS application that hosts this service.

So I changed my binding to:

       1: <bindings>

       2:     <basicHttpBinding>

       3:         <binding name="basicHttpBinding">

       4:             <security mode="TransportCredentialOnly">

       5:                 <transport clientCredentialType="Ntlm"/>

       6:             </security>

       7:         </binding>

       8:     </basicHttpBinding>

       9: </bindings>

Note: If you have a ”mex” endpoint you may get another error about ‘anonymous’ because that uses anonymous by default. If you do, you can delete the mex endpoint unless you need discoverability. Then you will need to remove anonymous from that as well.

After making these changes, Silverlight was able to call back into the ASP.NET project that it was loaded from and call a WCF service that was running inside SharePoint.

Developing for the Clouds

ASP.NET Debugging — Thu, 18 Jun 2009 18:33:28 GMT

I wanted to start a conversation with everyone on the thoughts around Cloud Computing. I have been using Azure for a while now and I have found some interesting things out about it.

Before I start talking about those things though, I wanted to see who was planning on using this technology or who is already using it. This would include other Cloud solutions as well.

If you are, what are you planning to do in the Cloud? How are you going about setting up testing, development, maintaining, monitoring in the Cloud?

I think that Cloud Computing is the future in a lot of ways and feel like things are going to change in a fundamental way in the not to distant future because of Cloud Computing. Do you agree?

Please keep in mind that I am not saying that Cloud Computing is a whole new way methodology, but I do think it will enable scenarios that weren’t possible before and will allow us to push the envelope of what we are capable of doing with a computer.

I look forward to hearing back from you and talking more about Azure and Cloud Computing.

Adventures with Silverlight 3.0 and SharePoint – Part 2

ASP.NET Debugging — Mon, 15 Jun 2009 20:02:14 GMT

Just a quick update on this. I had to make a few changes to my site and I now have it working!

To fix the master page problem, I needed to load it from code behind. Once I did that, I was able to have that show up. But then I had a problem of the Silverlight application didn’t show up at all.

To get around that I needed to get rid of the width and height settings from the Silverlight object. So I needed to change from using width=100% height=100% to style=”width: 700px; height: 700px”

After making that change, the only thing left was to move my connection string settings into the web.config file for SharePoint. After that was done, my Silverlight Navigation project loaded just fine in SharePoint and was able to use RIA Data Services.

I hope these two posts help anyone else looking to do this. Let me know if you run into any other problems or have any suggestions.