Steve Spencer's Blog

Blogging on Azure Stuff

System.Web.Mvc not found after deploying to Azure Web Apps using Release Manager

I’m currently evaluating Release Manager in Visual Studio Team Services and I am using it to deploy website to Azure Web Apps. I recently tried to deploy an Asp.Net MVC 4 application and ran into some issues.

I’ve created a build that packages and zips up my web application which runs successfully.I’ve linked a Release pipeline to this build and I can deploy to my test Azure site without any errors, but when I try and run the web application I get the following error:

Could not load file or assembly 'System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

image

I’m using Visual Studio 2013 with MVC as a nuget package.Looking at the properties of System.Web.Mvc I can see that it is set to Copy Local = True

image

I tried a few different things to try to get the assembly to be copied like redoing the nuget install and eventually I toggled the Copy Local to False, saved the project file and then set it back to true. When I looked at the diff of the project file I found an additional property

image

This seems to fix the build. When I checked this in and rebuild, System.Web.Mvc now appears in the zip file. The build was then release to Azure and the web app worked correctly.

Unhandled Messages with Azure Service Bus and RabbitMQ

One of the requirements for our messaging system is to be able to build a system to process messages and either

  1. Have a default handler and then add custom handlers as and when they are required without needing to recode the main system.
  2. Be notified if a message is put onto a topic and there isn’t a process to handle the message.

In RabbitMQ this is relatively straight forward and requires creating an alternate-exchange, adding it as a property to your main exchange and then creating a queue to service the alternate-exchange

 

IDictionary<String, Object> args2 = new Dictionary<String, Object>();

args2.Add("alternate-exchange", alternateExchangeName);

channel.ExchangeDeclare(mainExchangeName, "direct", false, false, args2);

channel.ExchangeDeclare(alternateExchangeName, "fanout");

// Adds a queue bound to the unhandled messages exchange

channel.QueueDeclare(unroutedMessagesQueueName, true, false, false, null);

channel.QueueBind(unroutedMessagesQueueName, alternateExchangeName, "");

Now when a message is published on the main exchange and there is no subscription to handle the message, then the message will automatically appear on the unrouted message queue. This solution will solve both the scenarios we were looking for.

I was interested however understanding how to do this in the Azure Service Bus and whilst it is possible isn’t not as straight forward and will require some code to setup. Topics can be configured to throw an exception if there is no subscription available to process the message when the message is sent. So When the topic is created it needs to be configured to enable this exception to be thrown.

NamespaceManager namespaceManager =

               NamespaceManager.CreateFromConnectionString(_ConnectionString);

TopicDescription td = new TopicDescription(topic)

{

          EnableFilteringMessagesBeforePublishing = true

};

await namespaceManager.CreateTopicAsync(td);

 

Now when a message is sent we need to handle the exception and do something with the message. This is the difference between RabbitMQ and Service Bus. In RabbitMQ the message will automatically end up in the unhandled message queue. In service bus we will need to actually add it to the unhandled message queue when the message is sent. This means that at each message producer, the code will need to handle the exception:

try

{

     client.Send(message);

}

catch(NoMatchingSubscriptionException ex)

{

     // Do something here to process the unhandled message

     // Probably put it on an unhandled message queue

}

Note, however, that if you had a subscription that was a catch all (for example logging all the messages) then unhandled messages would not appear as they are already being handled by the catch all subscription.

PowerShell DSC Composite Resources

When working with PowerShell DSC your scripts often get big and difficult to follow. If you are not careful you will end up copy and pasting configuration. I don’t like Copy/Paste coding so I was looking for a mechanism to allow me to reuse my DSC scripts. I came across Composite Resources.

Composite resources look very similar to you main DSC configuration but along with parameters they allow you to write reusable configuration. The following blog post has a good introduction to composite resources:

http://blogs.msdn.com/b/powershell/archive/2014/02/25/reusing-existing-configuration-scripts-in-powershell-desired-state-configuration.aspx

I followed this post but I had a few issues trying to get my composite resource to be recognised by my DSC configuration. The main issues is that the composite resource requires a very specific structure within which the files need to be put in order for it to be recognised. It then needs copying to somewhere on the DSC module path. On my computer this was C:\Program Files\WindowsPowerShell\Modules. The structure is as follows:

 

           image

MyModule.psd1 & MyCompositeResource.psd1 are manifest files created using New-ModuleManifest. This effectively creates a GUID for the module and the resource. Once these files are created open up MyCompositeResource.psd1 and edit the following line :

RootModule = ‘MyCompositeResource.schema.psm1'

To check to see if the module is configured and structured correctly, go to PowerShell and type:

Get-DscResource -Name MyCompositeResource

If it is configured correctly then PowerShell will return details of the module

ImplementedAs        Name                               Module            Properties

-------------                   ----                                    ------                 ----------

Composite               MyCompositeResource     MyModule       {ServiceName, exeFullPath, sourcePath, destinat...

If you want to use the composite resource on a pull server then the whole MyModules folder needs zipping and a checksum file creating, then copy it to the modules folder on your pull server where all the other modules reside.

This now works well until I added a Script resource to my composite resource. I was creating a composite resource to install a set of windows services and the process I was following required me to uninstall and then reinstall the service using a script. The script block worked fine until I had multiple services using the same composite resource. I then started getting errors when creating the MOF file complaining that I had duplicate keys for my script blocks.

“Add-NodeKeys : The key properties combination 'some script' is duplicated for keys 'GetScript,SetScript,TestScript' of resource 'Script' in node 'nodename'. Please make sure key properties are unique for each resource in a node”

After a bit of searching I found this post: https://www.briantist.com/how-to/use-duplicate-dsc-script-resources-in-loop/ which explains how to resolve the problem. I copied the Replace-Using script to the top of my composite resource file and then piped the GetScript, TestScript and SetScripts to Replace-Using

e.g.

Script Service.UrlAcl
{
    GetScript =  {$using:ServiceName + "UrlAclGet"} |Replace-Using
    TestScript =
    {
        if([String]::IsNullOrEmpty($using:UrlAcl))
        {
             Write-Verbose -Message "urlacl not configured in parameters"
            return $true                   
        }
        else
        {
           [String] $resp = (netsh http show urlacl url=$using:UrlAcl | findstr -i $using:UrlAcl)
           Write-Verbose -Message "netsh returned $resp for url $using:UrlAcl"
           if( [string]::IsNullOrEmpty($resp) -OR ($resp.IndexOf($using:UrlAcl) -eq -1) )
           {
                 # The url is not registered
                Write-Verbose -Message "urlacl=$using:UrlAcl not registered"
                return $false
            }
            else
            {
                Write-Verbose -Message "urlacl=$using:UrlAcl IS registered"
                    return $true
            }
          }
    } |Replace-Using
    SetScript =
    {            
        $fullun= $using:un
        $domainpos = $fullun.IndexOf("\")
        if ($domainpos -ne -1 )
        {
           $fullun=$fullun.Substring($domainpos+1)
        }
        Write-Verbose -Message "Setting urlacl= $using:UrlAcl for $fullun"
        netsh http add urlacl url=$using:UrlAcl user=$fullun

     } |Replace-Using
     DependsOn = "[Script]Service.Install"
    }

I now have a working composite resource that I can add to my pull server to configure up Windows Services

Unlock The Door Demo Software on GitHub

If you attended my DDD East Anglia talk “A Raspberry Pi2, Azure ML and Project Oxford to unlock that door!” where I integrate a Raspberry Pi running Windows 10 IoT core with the service bus , Project Oxford for face recognition and a Windows Store App to take my picture and hopefully unlock my door. Yes I did bring a door with me. Thanks for attending and for your nice comments.

I have started to put my code up on GitHub. The code for the Raspberry Pi is already there - https://github.com/sdspencer-mvp/RaspberryPi2-UnlockTheDoor. More will appear later as I tidy it up and remove all my config secrets Winking smile

I will be repeating this talk at Smart Devs in Hereford on 12 October 2015 and again at DDD North in Sunderland on 24 October 2015.

Windows 10 IoT Core New Release

I’ve just upgraded my Raspberry Pi 2 with Windows 10 IoT Core Build Number 10531.0 (download , release notes). It fixes an issue I’ve been having with setting the application the runs when the Pi first starts up. Prior to this release my application would start up the first time and then shutdown and be replaced by the default app. It would then not start up at power up again. Now my application starts up every time I power on my Raspberry Pi Smile

It is also possible to set the computer name and set the administrator password from the Raspberry Pi administration website. Previously this was done using PowerShell.

In order to navigate to the administration page you must first know either the machine name or ip address of your Raspberry Pi. This can be found in the Windows 10 IoT Core watcher application that runs after you have installed the IoT core SDK. To access the admin website either enter the address into a browser (http://<ipaddressornameofPi>:8080) or right click on the Pi in the IoT Core Watcher application and select “Web Browse Here”. You will need to enter the username Administrator plus your password to access the site.

image

Here  you can enter a new device name (machine name) as well as change the password. A reboot will be required if you change the name.

In order to set the start up app click the Apps link on the menu panel

image

You will need to ensure that you have first deployed your application to the Raspberry Pi. If you have debugged your application using Visual Studio then a debug version will already have been installed on the Raspberry Pi.

From the Installed Apps drop down select your applications and click the Set Default button. Your application should start and replace the Default App in the running apps list. You can check this by clicking reboot or cycling the power to the Raspberry Pi and your app should start up after the Raspberry Pi has booted.

Adding Multi-Factor Authentication to ADFS

I’ve been investigating how to wire up AD to ADFS and thanks to my friend James he pointed me in the direction of multifactor authentication. The post here explains how to add in multi-factor authentication (MFA) to ADFS. There were however a couple of areas that were not clear that needed additional research.

  1. How to get a config file into  the MFA provider
  2. How to send additional claims from the MFA provider
  3. How to customise the ADFS MFA portal pages

Adding configuration into the MFA is handled in the  OnAuthenticationPipelineLoad method in the AuthenticationAdapter class. The configData parameter contains a Data property which is a file stream that allows you access to the config file. The config file can be anything you want but you need to add it when you register your plugin with ADFS. Plugin registration is doen in Powershell and you need to add the configuration as follows:

Register-AdfsAuthenticationProvider -TypeName $typeName -Name "MFA_MyProvider" -Verbose -ConfigurationFilePath c:\mfa\config.xml  see here

In your OnAuthenticationPipelineLoad method you need to process the config file

public void OnAuthenticationPipelineLoad(IAuthenticationMethodConfigData configData)

{

    if (configData != null)

    {

        if (configData.Data != null)

        {

            // load the config file

            using (StreamReader reader = new StreamReader(configData.Data, Encoding.UTF8))

            {

                try

                {

                    string config = reader.ReadToEnd();

 

                    // Read your config here

                }

            }

        }

    }

}

 

Sending additional claims is achieved in the TryEndAuthentication method of the AuthenticationAdapter class. It should already be returning and authentication method as an array of claims. You can add additional claims to this array and return them through the claims out parameter. You will need to add rules in ADFS to pass through these claims to the application if they are required.

Customising the MFA portal is done through PowerShell details are found here:

http://thinketg.com/adfs-3-0-logon-page-customization/ & https://technet.microsoft.com/en-us/library/dn280950.aspx

 

Windows 10 IoT core project issues when upgrading to VS2015RTM

Just updated my VS2015 to RTM and tried to load in my blinky Iot Project for Raspberry Pi 2. It didn’t load and I was informed that the project required updating

clip_image001

Right clicking on the project offers the option to download updates

Selecting this takes you to:

https://msdn.microsoft.com/en-us/library/windows/apps/xaml/mt188198.aspx

It looks like all I can do is to create a new blank project and copy the existing project files over.

Created a new project and copied the contents of MainPage.xaml.cs and MainPage.Xaml over the contents of the files created in the new project. I found it was quicker to do this than to copy the files over manually. Also, change the namespace (if you created a project with a different name) in both MainPage.xaml.cs and MainPage.xaml. Add in all other files you are using by right clicking on the project and clicking Add Existing Items…

Need to add the following reference:

clip_image002

In the project properties: I selected remote debugger and entered the ip address of my raspberry pi.

When I tried to debug the deployment failed because the version of the remote debugger on the raspberry pi2 was out of date. In order to upgrade it I needed to also upgrade my Windows 10 to the latest version.( https://ms-iot.github.io/content/en-US/win10/SetupPCRPI.htm ) then reflash my raspberry pi 2 sd card ( https://ms-iot.github.io/content/en-US/win10/SetupRPI.htm)

I first updated my Win 10 VM but when I ran the WindowsIoTImageHelper it would not recognise the SD card of the host machine and I couldn’t seem to force it to use the SD card on the host. I then updated my surface Pro to the latest Windows 10 and repeated the process to reflash my Pi.

With all the upgrades completed my project now deploys and runs fine on my updated Raspberry PI2.

Raspberry Pi2 , Iot Core and Azure Service Bus

Using Raspberry Pi2 on Windows 10 IoT core has a number of challenges mainly due to the limitations of both the universal app APIs and also the lack of APIs that currently run on the platform. I specifically wanted to utilise Azure Service Bus Topics to send/receive messages on my Raspberry Pi2. After a bit of searching around I decided that the easiest way to achieve this was to use the Service Bus REST API. There are a number of samples included in the documentation:

Receiving a message: https://msdn.microsoft.com/en-us/library/azure/hh690923.aspx

Sending a message: https://msdn.microsoft.com/en-us/library/azure/hh690922.aspx

The full code for the sample uses WebClient but I needed to use HttpClient so I converted the samples accordingly.

[EDIT] The above links don't work anymore so I've published my code on GitHub https://github.com/sdspencer-mvp/RaspberryPi2-UnlockTheDoor/blob/master/UnlockTheDoor/MainPage.xaml.cs 

Sending a message to the service bus requires a POST and receive and delete requires a DELETE. The following code shows how this was achieved using HttpClient

private async void SendMessage(string baseAddress, string queueTopicName, string token, string body, IDictionary<string, string> properties)

{

    string fullAddress = baseAddress + queueTopicName + "/messages" + "?timeout=60&api-version=2013-08 ";

    await SendViaHttp(token, body, properties, fullAddress, HttpMethod.Post);

}

 

 

 

// Receives and deletes the next message from the given resource (queue, topic, or subscription)

// using the resourceName and an HTTP DELETE request.

private static async System.Threading.Tasks.Task <string> ReceiveAndDeleteMessageFromSubscription(string baseAddress, string topic, string subscription, string token, IDictionary<string, string> properties)

{

    string fullAddress = baseAddress + topic + "/Subscriptions/" + subscription + "/messages/head" + "?timeout=60";

    HttpResponseMessage response = await SendViaHttp(token, "", properties, fullAddress, HttpMethod.Delete);

    string content = "";

    if (response.IsSuccessStatusCode)

    {

        // we should have retrieved a message

        content = await response.Content.ReadAsStringAsync();

    }

    return content;

}

 

 

 

private static async System.Threading.Tasks.Task<HttpResponseMessage> SendViaHttp(string token, string body, IDictionary<string, string> properties, string fullAddress, HttpMethod httpMethod )

{

    HttpClient webClient = new HttpClient();

    HttpRequestMessage request = new HttpRequestMessage()

    {

        RequestUri = new Uri(fullAddress),

        Method = httpMethod ,

 

    };

    webClient.DefaultRequestHeaders.Add("Authorization", token);

 

    if (properties != null)

    {

        foreach (string property in properties.Keys)

        {

            request.Headers.Add(property, properties[property]);

        }

    }

    request.Content = new FormUrlEncodedContent(new[] { new KeyValuePair<string, string>("", body) });

    HttpResponseMessage response = await webClient.SendAsync(request);

    if (!response.IsSuccessStatusCode)

    {

        string error = string.Format("{0} : {1}", response.StatusCode, response.ReasonPhrase);

        throw new Exception(error);

    }

    return response;

}

 

There was an issue with the GetSASToken method as some of the encryption classes weren't supported on the Universal App so I converted it to the following:

private string GetSASToken(string baseAddress, string SASKeyName, string SASKeyValue)

{

    TimeSpan fromEpochStart = DateTime.UtcNow - new DateTime(1970, 1, 1);

    string expiry = Convert.ToString((int)fromEpochStart.TotalSeconds + 3600);

    string stringToSign = WebUtility.UrlEncode(baseAddress) + "\n" + expiry;

    string hmac = GetSHA256Key(Encoding.UTF8.GetBytes(SASKeyValue), stringToSign);

    string hash = HmacSha256(SASKeyValue, stringToSign);

    string sasToken = String.Format(CultureInfo.InvariantCulture, "SharedAccessSignature sr={0}&sig={1}&se={2}&skn={3}",

        WebUtility.UrlEncode(baseAddress), WebUtility.UrlEncode(hash), expiry, SASKeyName);

    return sasToken;

}

 

 

public string HmacSha256(string secretKey, string value)

{

    // Move strings to buffers.

    var key = CryptographicBuffer.ConvertStringToBinary(secretKey, BinaryStringEncoding.Utf8);

    var msg = CryptographicBuffer.ConvertStringToBinary(value, BinaryStringEncoding.Utf8);

 

    // Create HMAC.

    var objMacProv = MacAlgorithmProvider.OpenAlgorithm(MacAlgorithmNames.HmacSha256);

    var hash = objMacProv.CreateHash(key);

    hash.Append(msg);

    return CryptographicBuffer.EncodeToBase64String(hash.GetValueAndReset());

}

 

This allowed me to send and receive messages on my Raspberry Pi2 using IoT core. I created the subscriptions for the topic using a separate app using the .NET SDK which is cheating I guess, but I’ll get around to converting it at some point.

 

In order to use this the following parameters are used:

 

SendMessage( BaseAddress, Username, Token, MessageBody, MessageProperties)

 

BaseAddress is “https://<yournamespace>.servicebus.windows.net/”

 

Token is the return value from the GetSASToken method. using the same base address as above and the KeyName and Key are obtained from the Azure portal and is of the format

 

Endpoint=sb://<yournamespace>.servicebus.windows.net/;SharedAccessKeyName=<KeyName>;SharedAccessKey=<Key>.

 

MessageBody – This is the string value of the message body

 

MessageProperties are a Dictionary containing name/value pairs that will get added to the Request headers. For example I have set the message properties when I press the door bell button on my Raspberry PI2

 

Dictionary<string, string> properties = new Dictionary<string, string>();

properties.Add("Priority", "High");

properties.Add("MessageType", "Command");

properties.Add("Command", "BingBong");

 

These are added to the service bus message and allow me to have subscriptions that filer on Command message types as well as the specific command of BingBong

 

Receiving messages are a bit trickier as we need to create a separate task that is continually running. Once the message is received we need to get back to the main tread to execute the action for the message

await Task.Run(async () =>

{

.

.

.

string message = await ReceiveAndDeleteMessageFromSubscription(_BaseAddress

,_TopicName

, _SubscriptionName

, token, null);

 if (message.Contains("Unlock"))

{

   await Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(

      CoreDispatcherPriority.Normal,

      () =>

      {

          SwitchLED(false);

     });

}

 

.

.

}

 

You may want to put a delay in this if receiving the messages causes the app to slow down due to the message loop hogging all the resources. There’s a default timeout in the call to SendAsync and this will automatically slow the thread down.

 

I now have a working Raspberry PI2 that can send and receive message to the Azure Service bus. I’ve created a test win forms app that allows me to send messages to the Service bus and it allows me to control the Raspberry Pi2 remotely. The next phase is to build a workflow engine that hooks up to the service bus and allows me to automatically control the Raspberry Pi. 

Issues setting up Raspberry Pi, Windows 10 IoT core and Visual Studio on a Windows 10 VM

After setting up my Surface Pro with Windows 10 and IoT core I decided that in order to demo it all I needed a Windows 10 VM with it all on. I had a couple of issues that I didn’t get on my Surface Pro.

The first issue I had was that the Windows IoT core watcher application would not run properly and kept shutting down. This is a known bug and has a work around:

Launch the "Developer Command Prompt for VS2015" as Administrator
change the working directory over to "C:\Program Files (x86)\Microsoft IoT"
sn -Vr WindowsIoTCoreWatcher.exe
corflags WindowsIoTCoreWatcher.exe /32BIT+ /FORCE

 

The second issue was Visual Studio couldn’t connect to TFS online. When I tried to manage connections I got the following error:

SplitterDistance must be between Panel1MinSize and Width - Panel2MinSize.

This seems to happen on both VS 2015 Enterprise RC and Community RC editions. I found a work around as follows:

Open up Team Foundation Server online at <youraccount>.visualstudio.com. Click code, then navigate to the project you want to open, click on the solution file which then opens the solution in the web editor. Click the visual studio icon and VS opens with the team project now in team explorer. Close VS and open it again and your team project should still be  connected to team explorer

 

Now with Visual Studio working I needed to set Windows into developer mode. This can be done as follows:

Start->settings->Update & Security -> For Developers. However, when I tried this the setting page kept closing. You can also use the Group Policy editor (Gpedit.msc) as follows:

https://msdn.microsoft.com/en-us/library/windows/apps/dn706236.aspx

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Raspberry Pi and Windows IoT Core – Push Buttons and Relays

In my previous Raspberry Pi Post I talked about using the Raspberry Pi to turn an LED on an off. Now whilst this is pretty, its not really that useful. So I wanted to use the same program but to turn on something that needed a bit more power than an LED. I’d recently acquired a solenoid (a coil with a bolt that gets draw towards the magnetised coil when 12v is applied to the solenoid’s coil). Now my Pi doesn’t have enough power on its own to drive the solenoid so I needed a mechanism to apply 12v to the coil from a 3.3V output that the PI delivers. This meant I had to think back to my school days, which in my case is a difficult task :-). I remembered that I could use a transistor to turn  on something with a bigger current from a smaller one.  I decided that as the Pi can supply both 3.3V and 5V I would use a 5V relay and a transistor to allow me to turn on a separate 12v supply to the solenoid. I tried to calculate the correct resistors for the circuit but I failed miserably so in the end I decided trial and error was my best plan. I used a NPN transistor and a resistor and I also combined the LED and resistor from the previous post. The other change that I wanted to do was to remove the timer, that was being used to turn the LED on and off, and replace it with a push button switch.

The following shows the circuit I used.

 image

I should really use a diode across the resistor to protect the transistor and I’ve even used my soldering iron without burning my fingers.

For information, the following image shows the assignment of pins for the Raspberry Pi 2:

image

Anyway, In order to change the code to use a push button I took the sample https://www.hackster.io/windowsiot/push-button-sample and added the push button code to my blinky sample and removed the timer turning on the LED.

In order to use the push button I needed to configure one of the GPIO pins for input rather than output that was used for turning on the LED. I still needed to use a timer, as I needed to read the push button pin on a regular basis to see when the input changed to low when the button was pressed.I set the time to 250 ms so that I didn’t have to hold the button down too long for it to register,  but not too long that the timer  would hog all the resources on the PI.

Now when I press the button the LED turns on, the relay clicks and the solenoid pulls the bolt across. It made me jump when I first connected it up as the solenoid made quite a loud bang and I though I’d blown something up!!

I think I know enough now of how to use the GPIO on the Raspberry PI so I am looking at how I can now connect the PI up to Azure and make it part of a distributed system.

More on this to come……