Add role-based authorisation based on Azure AD group membership

This post describes how to use Azure AD groups for role-based authorisation in your ASP.NET web application.

Practical Microsoft Azure Active Directory Blog Series

This post is part of the Practical Microsoft Azure Active Directory Blog Series.

Add role-based authorisation based on Azure AD group membership

These instructions will help you easily add role-based authorisation based on Azure AD group membership to your existing ASP.NET application with Azure AD authentication.  The links show either a commit from the example project or to relevant documentation.

Note: Ignore the ...‘s and replace the {SPECIFIED_VALUES} with the correct values.

  1. Create groups in your Azure AD tenant
  2. Assign your users to relevant groups
  3. Configure your Azure AD application to have application permissions to read directory data from Azure Active Directory
    • If you get a “Insufficient privileges to complete the operation.” exception then you might need to wait for a few minutes or an hour since it seems to cache the old permissions
  4. In the Configure tab of your Azure AD application create a key in the keys section and copy it
  5. Configure the client id of your Azure AD application and the key you created in the last step in your web.config file
      <appSettings>
        ...
        <add key="ida:ClientId" value="{AZURE_AD_APP_CLIENT_ID}" />
        <add key="ida:Password" value="{AZURE_AD_APP_KEY}" />
      </appSettings>
    
  6. Install-Package Microsoft.Azure.ActiveDirectory.GraphClient -Version 1.0.3
  7. Install-Package Microsoft.IdentityModel.Clients.ActiveDirectory
  8. Create an AzureADGraphConnection class:
    Infrastructure\Auth\AzureADGraphConnection.cs
    
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Security.Claims;
    using Microsoft.Azure.ActiveDirectory.GraphClient;
    using Microsoft.IdentityModel.Clients.ActiveDirectory;
    
    namespace {YOUR_NAMESPACE}.Infrastructure.Auth
    {
        public interface IAzureADGraphConnection
        {
            IList<string> GetRolesForUser(ClaimsPrincipal userPrincipal);
        }
    
        public class AzureADGraphConnection : IAzureADGraphConnection
        {
            const string Resource = "https://graph.windows.net";
            public readonly Guid ClientRequestId = Guid.NewGuid();
            private readonly GraphConnection _graphConnection;
    
            public AzureADGraphConnection(string tenantName, string clientId, string clientSecret)
            {
                var authenticationContext = new AuthenticationContext("https://login.windows.net/" + tenantName, false);
                var clientCred = new ClientCredential(clientId, clientSecret);
                var token = authenticationContext.AcquireToken(Resource, clientCred).AccessToken;
    
                _graphConnection = new GraphConnection(token, ClientRequestId);
            }
    
            public IList<string> GetRolesForUser(ClaimsPrincipal userPrincipal)
            {
                return _graphConnection.GetMemberGroups(new User(userPrincipal.Identity.Name), true)
                    .Select(groupId => _graphConnection.Get<Group>(groupId))
                    .Where(g => g != null)
                    .Select(g => g.DisplayName)
                    .ToList();
            }
        }
    }
    
  9. Create an AzureADGraphClaimsAuthenticationManager class:
    Infrastructure\Auth\AzureADGraphClaimsAuthenticationManager.cs
    
    using System.Configuration;
    using System.Security.Claims;
    
    namespace AzureAdMvcExample.Infrastructure.Auth
    {
        public class AzureADGraphClaimsAuthenticationManager : ClaimsAuthenticationManager
        {
            public override ClaimsPrincipal Authenticate(string resourceName, ClaimsPrincipal incomingPrincipal)
            {
                if (incomingPrincipal == null || !incomingPrincipal.Identity.IsAuthenticated)
                    return incomingPrincipal;
    
                // Ideally this should be the code below so the connection is resolved from a DI container, but for simplicity of the demo I'll leave it as a new statement
                //var graphConnection = DependencyResolver.Current.GetService<IAzureADGraphConnection>();
                var graphConnection = new AzureADGraphConnection(
                    ConfigurationManager.AppSettings["AzureADTenant"],
                    ConfigurationManager.AppSettings["ida:ClientId"],
                    ConfigurationManager.AppSettings["ida:Password"]);
    
                var roles = graphConnection.GetRolesForUser(incomingPrincipal);
                foreach (var r in roles)
                    ((ClaimsIdentity)incomingPrincipal.Identity).AddClaim(
                        new Claim(ClaimTypes.Role, r, ClaimValueTypes.String, "GRAPH"));
                return incomingPrincipal;
            }
        }
    }
    
  10. Configure your application to use the AzureADGraphClaimsAuthenticationManager class for processing claims-based authentication in your web.config file:
      <system.identityModel>
        <identityConfiguration>
          <claimsAuthenticationManager type="{YOUR_NAMESPACE}.Infrastructure.Auth.AzureADGraphClaimsAuthenticationManager, {YOUR_ASSEMBLY_NAME}" />
          ...
        </identityConfiguration>
      </system.identityModel>
    
  11. Add [Authorize(Roles = "{AZURE_AD_GROUP_NAME}")] to any controller or action you want to restrict by role and call User.IsInRole("{AZURE_AD_GROUP_NAME}") to check if a user is a member of a particular group

Explaining the code

Microsoft.Azure.ActiveDirectory.GraphClient and AzureADGraphConnection

The ActiveDirectory.GraphClient provides a wrapper over the Azure AD Graph API, which allows you to query the users, groups, etc.

The AzureADGraphConnection class constructs a graph client connection and a method to take a user and return a list of the groups that user is a member of.

This is needed because the claims that the Azure AD token comes with by default do not include any roles.

AzureADGraphClaimsAuthenticationManager

This class provides a claims authentication manager that hooks into the point that authentication occurs and augments the Claims Principal that is generated by default by getting the Azure AD Groups that the user is a member of (via AzureADGraphConnection) and turning them into a ClaimTypes.Role claim. ClaimTypes.Role is the claim type that automatically hooks into ASP.NETs roles processing.

The web.config change is how you override the Claims Authentication Manager.

Using an enum for roles

To avoid the use of magic strings in your application and assuming the group names in AD are relatively stable you can encapsulate them in an enum. There is a corresponding commit in the example project that demonstrates how to do it.

This involves three main steps:

  1. Define an enum with your roles and using the [Description] attribute to tag each role with the Display Name of the equivalent Azure AD group
  2. Parse the group name into the corresponding enum value by using Humanizer.Dehumanize in AzureADGraphConnection
  3. Create an AuthorizeRolesAttribute that extends AuthorizeAttribute and an extension on IClaimsPrincipal that provides an IsInRole method that both take the enum you defined rather than magic strings to define the roles

Explaining the code behind authenticating MVC5 app with Azure AD

This post explains the code outlined in the last post on installing Azure AD authentication to an existing (or new) ASP.NET MVC 5 (or 3 or 4) application.

Practical Microsoft Azure Active Directory Blog Series

This post is part of the Practical Microsoft Azure Active Directory Blog Series.

Microsoft.Owin.Security.ActiveDirectory

The Microsoft.Owin.Security.ActiveDirectory package is part of the Katana project, which produces a bunch of libraries that build on top of Owin.

It allows your application to accept a Bearer Authorization header in the HTTP request that contains a JSON Web Token (JWT) token issued from Azure AD and will create a ClaimsPrincipal in the thread from that token. This is mainly useful for creating Web APIs and thus is optional if you just need web authentication.

Note: if you use bearer tokens make sure you request resources with HTTPS.

This package is enabled up by the app.UseWindowsAzureActiveDirectoryBearerAuthentication(...) call in Startup.cs.

There are two configurations in the Startup.cs code to configure the package:

  • TokenValidationParameters – this controls how tokens that are presented by a user are checked for validity
    • In the code example in the previous blog post we set ValidAudience, which ensures that any tokens presented are valid for the given audience (alternatively, you can use ValidAudiences if you want to accept tokens from multiple audiences)
    • There is more information later in this post about audiences
  • Tenant – This sets which Azure AD tenant you are accepting tokens from

WSFederationAuthenticationModule (WS-FAM) and SessionAuthenticationModule (SAM)

These modules are part of WIF via System.IdentityModel.Services and are the mechanism by which the authentication hooks into ASP.NET and works. For this to work you need to enter a bunch of code in web.config, but Microsoft is currently working on OWIN-only components that hide all of that away and provide for a much simpler configuration so in the future you won’t need to do any of this. At the time of writing the samples don’t quite seem to work (for me at least) yet, so for now it makes sense to keep using the WIF modules, but it’s worth keeping out an eye on what happens with the samples Microsoft are working on, in particular the OpenIdConnect one.

So what do these WIF modules do? From the WSFederationAuthenticationModule documentation:

When an unauthenticated user tries to access a protected resource, the [Relying Party (RP)] returns a “401 authorization denied” HTTP response. The WS-FAM intercepts this response instead of allowing the client to receive it, then it redirects the user to the specified [Security Token Service (STS)]. The STS issues a security token, which the WS-FAM again intercepts. The WS-FAM uses the token to create an instance of ClaimsPrincipal for the authenticated user, which enables regular .NET Framework authorization mechanisms to function.

Because HTTP is stateless, we need a way to avoid repeating this whole process every time that the user tries to access another protected resource. This is where the SessionAuthenticationModule comes in. When the STS issues a security token for the user, SessionAuthenticationModule also creates a session security token for the user and puts it in a cookie. On subsequent requests, the SessionAuthenticationModule intercepts this cookie and uses it to reconstruct the user’s ClaimsPrincipal.

From the SessionAuthenticationModule documentation:

The SAM adds its OnAuthenticateRequest event handler to the HttpApplication.AuthenticateRequest event in the ASP.NET pipeline. This handler intercepts sign-in requests, and, if there is a session cookie, deserializes it into a session token, and sets the Thread.CurrentPrincipal and HttpContext.User properties to the claims principal contained in the session token.

These modules are then configured by the system.identityModel and system.identityModel.services sections in web.config.

issuerNameRegistry and signing key refresh

This configures which tenants and issuers of authentication your application trusts as well as the thumbprint of their public signing key certificates.

The certificate thumbprints will change over time for security reasons so hardcoding the keys in web.config is not a good option hence you need to make sure to implement code that changes the keys for you. The simplest, built-in way to do that is using ValidatingIssuerNameRegistry.WriteToConfig, which updates web.config for you automatically when it changes. That’s the instruction that was given in the last blog post.

Another option is to store the keys in a database, which is what the default code that Visual Studio’s Identity and Access Tools add (using EntityFramework). Yet another option is to store them in-memory and there is a class floating about that you can use to do that. Storing it in-memory is probably the nicest option.

Audiences and realm

The audienceUris configuration in web.config allows your application to control a list of identifiers that will be accepted for the scope of a presented authentication token (in Azure AD this maps to the App ID URI of your Azure AD application).

The realm attribute in the wsFederation element of the federationConfiguration in web.config tells the WSFederationAuthenticationModule to specify the WS Federation wtrealm to use for the request, which identifies the security realm that will be used for the request. For Azure AD this provides the App ID URI of the Azure AD application that should be used to service the authentication request. Thus, this value will generally be the same as the audience you configured unless you are doing multi-tenancy.

The difference between realm and audience is explained in this StackOverflow post.

securityTokenHandlers

A security token handler provides a way for interpreting a security token of some sort into a Claims Principal for a given request. The code in the previous post gets you to remove the default handler that takes care of looking at cookies in the request, SessionSecurityTokenHandler, because it uses DPAPI to encrypt and decrypt the cookies and that doesn’t work in an environment with multiple web servers. Instead you are guided to add a MachineKeySessionSecurityTokenHandler, which uses the machine key to encrypt and decrypt the cookie.

The configured securityTokenHandler will be what the SessionAuthenticationModule will make use of to store and retrieve the token from and to the cookie.

certificateValidation

On first thought, it might be confusing to see that certificate validation is turned off, but this is by design. The validating issuer name registry as explained above is a replacement for standard certificate validation. The only information that I’ve been able to find that explains this further is a post on the MSDN forums.

To illustrate what happens when you try using certificate validation, you can change certificateValidationMode to, say, ChainTrust and then you will get the following error:

The X.509 certificate CN=accounts.accesscontrol.windows.net chain building failed. The certificate that was used has a trust chain that cannot be verified. Replace the certificate or change the certificateValidationMode. A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider.

HTTPS

You can ensure that the security cookie is set to require SSL with the requireSSL attribute of the cookieHandler element in web.config and ensure that the authentication requests require a HTTPS connection with the requireHttps attribute of the wsFederation element in web.config.

In production environments it’s absolutely essential that you set both to true otherwise you are vulnerable to MITM attacks. You can set them to true locally if you use https with IIS Express or via a self-signed cert with IIS.

issuer

Setting this attribute on the wsFederation element in web.config determines where sign-in and sign-out requests are redirected.

passiveRedirectEnabled

Setting this attribute on the wsFederation element in web.config to true allows the WSFederationAuthenticationModule to automatically redirect the user to the authentication server in the event of a 401. Without this set to true you would need to explicitly call SignIn to log the user in.

reply

Setting this attribute on the wsFederation element in web.config allows the application to control where the user is taken after they authenticate. The last post didn’t tell you to set it because by default it’s not required. When using Azure AD, in the instance that it’s not specified, the user will be redirected to the first Reply URL specified in the Azure AD application.

This requires that you can only have a one-to-one relationship between an Azure AD application and a web application requiring authentication. You can actually add multiple reply URLs to your Azure AD application though. This fact in combination with the reply attribute means that you can support multiple web applications (e.g. local, dev, staging, prod or even just different applications altogether) with the same Azure AD application. You just need to config transform your web.config file for each different environment as explained in this post.

If you are in a situation where you want to only change an app setting to control the reply URL (e.g. you are using VSO to deploy different branches to separate Azure Web Sites) then you can change the reply URL in code like so:

    public static class IdentityConfig
    {
        public static void ConfigureIdentity()
        {
            ...
            FederatedAuthentication.FederationConfigurationCreated += FederatedAuthentication_FederationConfigurationCreated;
        }

        ...

        private static void FederatedAuthentication_FederationConfigurationCreated(object sender, FederationConfigurationCreatedEventArgs e)
        {
            var federationConfiguration = new FederationConfiguration();
            federationConfiguration.WsFederationConfiguration.Reply =
                ConfigurationManager.AppSettings["AuthenticationReplyUrl"];
            e.FederationConfiguration = federationConfiguration;
        }
    }

Anti-forgery config

AntiForgeryConfig.UniqueClaimTypeIdentifier allows you to set which claim from the claims-based authentication token can be used to uniquely identify a user for the purposes of creating an appropriate anti-forgery token. Side note: this post about anti-forgery token is great. The claim that was shown in the last post is the correct one to use for Azure AD.

Logout

There are two parts to the logout code in the last post. Firstly, there is a call to the SessionAuthenticationModule, which will cause the cookie you have on the current site to be dropped by your browser. Secondly, there is a redirect to a URL that the WS Federation code generates that will log you out of the source system (in this case your Azure AD session) and then redirect you back to a callback page with [AllowAnonymous] so they don’t get redirected back to login again straight away.

Announcing AspNet.Mvc.Grid

Whenever I need to display tables of data in an ASP.NET MVC application I end up pulling in the MVCContrib library to use its Grid Helper.

The Grid helper is really cool, it allows you to take a class like:

public class Person
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
    public DateTime DateOfBirth { get; set; }
}

And create a Razor view like the following (including appending some Bootstrap classes):

@model IEnumerable<Person>

<h1>Person List</h1>

@Html.Grid(Model).Columns(cb =>
{
    cb.For(p => Html.ActionLink(p.Name, "Detail", "People", new {p.Id}, null)).Named("Name");
    cb.For(p => p.Email);
    cb.For(p => p.DateOfBirth);

}).Attributes(@class => "table table-striped table-hover table-condensed").HeaderRowAttributes(new Dictionary<string, object> { { "class", "active" } })

This will then output HTML like the following:

<h1>Person List</h1>
<table class="table table-striped table-hover table-condensed">
   <thead>
      <tr class="active">
         <th>Name</th>
         <th>Email</th>
         <th>Date Of Birth</th>
      </tr>
   </thead>
   <tbody>
      <tr class="gridrow">
         <td><a href="/People/Detail/1">Name1</a></td>
         <td>Email1</td>
         <td>19/08/2014 12:00:00 AM</td>
      </tr>
      <tr class="gridrow_alternate">
         <td><a href="/People/Detail/2">Name2</a></td>
         <td>Email2</td>
         <td>20/08/2014 12:00:00 AM</td>
      </tr>
      <tr class="gridrow">
         <td><a href="/People/Detail/3">Name3</a></td>
         <td>Email3</td>
         <td>21/08/2014 12:00:00 AM</td>
      </tr>
   </tbody>
</table>

This means you don’t have to render out the nasty, tedious table HTML, it takes care of creating the thead and tbody for you, it’s type safe (thanks Razor!) and there are some sensible defaults that save you time (like inferring the th title from the property name).

The problem with MvcContrib

There is however a few big problems with MvcContrib – it’s not really kept very maintained and it contains A LOT of bloat in there for stuff you will never need (and frankly shouldn’t use).

To be honest, out of everything in there the Grid is the only thing I would touch.

It does actually have an MVC5 package, but it contains a reference to Mvc4Futures and this can actually have a really bad impact if you are using MVC5 due to one of the breaking changes in MVC5. If you have code that is assembly scanning the current AppDomain for instance then you will soon come across this error:

Inheritance security rules violated while overriding member: ‘Microsoft.Web.Mvc.CreditCardAttribute.GetClientValidationRules(System.Web.Mvc.ModelMetadata, System.Web.Mvc.ControllerContext)’. Security accessibility of the overriding method must match the security accessibility of the method being overriden.

Creating AspNet.Mvc.Grid

Given that roadblock on a current project, and given I don’t really want to pull in all the bloat of MvcContrib I decided to pull out the Grid code from MvcContrib and put it into it’s own library that targets .NET 4.5 and MVC 5. This is allowed under the Apache 2.0 license the MvcContrib code is licensed for.

Hence, I’d like to announce the AspNet.Mvc.Grid library! It has been published to NuGet as per usual.

The only difference you will notice between it and MvcContrib is that the namespaces are different. This was a conscious decision to make the library less confusing for completely new users.

Enjoy!

Deployment and Development using PhoneGap Build for a Cordova/PhoneGap app

I recently worked on a project to build a mobile app in iOS and Android. The team decided to use Cordova and Ionic Framework to build it. I highly recommend Ionic – it’s an amazingly productive and feature-rich framework with a really responsive development team! It enabled us to use AngularJS (and the application structure and maintenance advantages that affords) and really sped up the development time in a number of ways. We were also able to get an almost-native performance experience for the application using features like collection repeat (virtualised list) as well as the in-built performance tuning the Ionic team have performed.

When it was time to set up an automated build pipeline we settled on using PhoneGap Build and its API which we then called from OctopusDeploy as part of a NuGet package we created.

PhoneGap Build is Adobe’s cloud build service that can build iOS, Android, Windows Phone etc. apps for you based on a zip file with your Cordova/PhoneGap files.

We decided on PhoneGap Build because:

  • It has been around a while (i.e. it’s relatively mature)
  • It’s backed by a big name (Adobe)
  • It has a decent API
  • It meant we didn’t have to set up a Mac server, which would have been a pain
  • It’s free for a single project :)

This post covers how we set up our automated deployment pipeline for our native apps using OctopusDeploy and PhoneGap Build. I have also published a companion post that covers everything you need to know about PhoneGap Build (read: what I wish I knew before I started using PhoneGap Build because it’s darn confusing!).

Deployment pipeline

This is the deployment pipeline we ended up with:

  1. Developer commits a change, submits a pull request and that pull request gets merged
  2. Our TeamCity continuous integration server compiles the server-side code, runs server-side code tests and runs client-side (app) tests
  3. If all is well then a NuGet package is created for the server-side code and a NuGet package is created for the app – both are pushed to OctopusDeploy and the server-side code is deployed to a staging environment (including a web server version of the app)
    • Native functionality wouldn’t work, but you could access and use the bulk of the app to test it out
    • To test native functionality developers could easily manually provision a staging version of the app if they plugged a phone into their computer via a USB cable and executed a particular script
  4. The product owner logs into OctopusDeploy and promotes the app to production from staging whereupon OctopusDeploy would:
    • Deploy the server-side code to the production environment
    • Use the PhoneGap Build API to build an iOS version with an over-the-air compatible provisioning profile
    • Download the over-the-air .ipa
      • Upload this .ipa to Azure blob storage
      • Beta testers could then download the latest version by visiting a html page linking to the package (see below for details)
    • Build the production Android and iOS versions of the app using the PhoneGap Build API
  5. The product owner then logs on to the PhoneGap Build site, downloads the .ipa / .apk files and uploads them to the respective app stores

End result

I personally wasn’t completely satisfied with this because I didn’t like the manual step at the end, however, apparently app store deployments are stuck in the 90s so unless you want to screen-scrape the respective app stores you have to manually log in and upload the deployment file. Regardless, the end result was good:

  • Production deployments were the same binaries/content that were tested on the CI server and that had been successfully deployed and manually tested in the staging environment
  • We could go from developer commit to production in a few minutes (ignoring app store approval/roll-out times; remember – stuck in the 90s)
  • The product owner had complete control to deploy any version of the app he wanted to and it was easy for him to do so

How we did it

I have published the NodeJS script we used to automate the PhoneGap Build API to a Gist. It contains a very reusable wrapper around a PhoneGap Build API NodeJS library that makes it dead easy to write your own workflow in a very succinct manner.

To generate the zip file the NodeJS script used we simply grabbed the www directory (including config.xml) from our repository and zipped it up. That zip file and the NodeJS scripts went into the NuGet package that OctopusDeploy deployed when the app was promoted to production (we made this happen on a Tentacle residing on the OctopusDeploy server). I have published how we generated that NuGet package to a Gist as well (including how to set up over-the-air).

Further notes

Some notes about our approach:

  • Because we were able to make our backend apis deploy to production at the same time as generating our production app packages we were assured that the correct version of the backend was always available when the apps were deployed to the respective app stores.
  • It was important for us to make sure that our backend api didn’t have any breaking changes otherwise existing app deployments (and any lingering ones where people haven’t updated) would break – usual API management/versioning practices apply.
  • Whenever we wanted to add new Beta testers the provisioning profile for over-the-air needed to be re-uploaded to PhoneGap Build
    • Unfortunately, PhoneGap Build requires you upload this alongside the private key – thus requiring someone with access to PhoneGap Build, the private key and the iOS developer account – it’s actually quite a convoluted process so I’ve also published the instructions we provided to the person responsible for managing the Beta testing group to a Gist to illustrate
  • We stored the passwords for the Android Keystore and iOS private keys as sensitive variables in OctopusDeploy so nobody needed to ever see them after they had been generated and stored in a password safe
    • This meant the only secret that was ever exposed on a regular basis was the password-protected over-the-air private key whenever a Beta tester was added

TestFlight

While we didn’t use it, it’s worth pointing out TestFlight. It’s a free service that gives you the ability to more easily keep track of a list of testers, their UUIDs, informing them of updates and automatically creating and hosting the necessary files for over-the-air. It contains an API that allows you to upload your .ipa to and it should be simple enough to take the scripts I published above and upload a .ipa to TestFlight rather than Azure Blob Storage if you are interested in doing that.

Final Thoughts

PhoneGap Build is a useful and powerful service. As outlined in my companion post, it’s very different to Cordova/PhoneGap locally and this, combined with confusing documentation, resulted in me growing a strong dislike of PhoneGap Build while using it.

In writing my companion post however, I’ve been forced to understand it a lot more and I now think that as long as you have weighed up the pros and cons and still feel it’s the right fit then it’s a useful service and shouldn’t be discounted outright.

Developing ASP.NET web applications with IIS

When you File -> New Project an ASP.NET application in Visual Studio and then F5 by default it will spin up IIS Express and navigate to the site for you.

IIS Express is pretty cool – it runs under your user account so no need to mess around with elevated privileges, it has most of the power of IIS (think web.config) and it “just works” out of the box without extra configuration needed across all dev machines :)

For projects that I work on every day though, I really dislike using IIS Express as a development server for the following reasons:

  • It will randomly crash
  • When it crashes I have to F5 or Ctrl+F5 in Visual Studio to restart it – I can’t just go to the last url it was deployed to (e.g. http://localhost:port/)
  • If your code has an uncaught exception then a crash dialog pops up in your taskbar in a way that isn’t obvious and requires you to click a button until the code continues running (this can be very confusing)
  • Setting up a custom domain is tricky to do, is a tedious manual process and can’t run on port 80 side-by-side with proper IIS
    • Using a custom domain is often essential too – think sharing cookies between domains or performing something like integrating with third parties where you need to provide a URL other than localhost

Part of the reason IIS Express exists is because setting up IIS with a site is not a trivial process. However, when you do eventually get it set up I usually find it works great from then on:

  • It’s stable
  • The URL is always available – you don’t have to use Visual Studio at all
  • Uncaught exceptions behave as expected
  • Custom domains are easy in both the IIS Manager GUI and via a variety of commandline options

In order to reduce the pain involved with setting up IIS I do two things:

  • I modify my Visual Studio taskbar icon to always run as admin (necessary to open a project bound to IIS)
  • I add a Developer Setup script to the project that developers must run once when they first clone the repository that sets up everything up for them in a matter of seconds (hopefully giving the same Open Solution -> F5 and start developinging experience)
    • I’ve added an example of such a script to a Gist – the script also includes setting up the hosts file and a SQL Express database
    • I can’t claim full credit for the script – it’s been a collaborative effort over a number of projects by all of the Readifarians I’ve worked with :D

Scripted/Automated installation script to set up Cordova/PhoneGap and Android on Windows

I recently worked on a Cordova project and one of the things we found is that it’s an absolute pain to set up a development environment since there is a whole bunch of tools that need to be downloaded and installed and configured in specific ways.

We ended up creating a page in our project’s OneNote notebook with developer setup instructions, but even though we were using Chocolatey it was still a tedious process with numerous console restarts to refresh environment variables (that had to be manually set).

In the process of writing a post on Cordova I wanted to check something and realised I had repaved my machine since the last time I installed the Android SDK / Cordova etc.

I consulted the OneNote page we had created and looked in despair at the instructions. What a PITA! So what did I do?

I spun up a Windows Azure VM and stumbled through creating a PowerShell script to automate the setup. Then I spun up a second VM to check that the script worked :). Then I deleted both of them – probably cost a few cents and the servers had a really fast download speed so the installations were really quick. God I love the cloud :D

I’ve uploaded it to a Gist. If you are setting up a PhoneGap/Cordova & Android development environment then I’m sure it will be useful to you.

Enjoy!

My stance on Azure Worker Roles

tl;dr 99% of the time Worker Role is not the right solution. Read on for more info.

Worker Role Deployments

I quite often get asked by people about the best way to deploy Worker Roles because it is a pain – as an Azure Cloud Service the deployment time of a Worker Role is 8-15+ minutes. In the age of continuous delivery and short feedback loops this is unacceptable (as I have said all along).

On the surface though, Worker Roles are the most appropriate and robust way to deploy heavy background processing workloads in Azure. So what do we do?

Web Jobs

The advice I generally give people when deploying websites to Azure is to use Azure Web Sites unless there is something that requires them to use Web Roles (and use Virtual Machines as a last resort). That way you are left with the best possible development, deployment, debugging and support experience possible for your application.

Now that Web Jobs have been released for a while and have a level of maturity and stability I have been giving the same sort of advice when it comes to background processing: if you have a workload that can run on the Azure Web Sites platform (e.g. doesn’t need registry/COM+/GDI+/elevated privileges/custom software installed/mounted drives/Virtual Network/custom certificates etc.) and it doesn’t have intensive CPU or memory resource usage then use Web Jobs.

I should note that when deploying Web Jobs you can deploy them automatically using the WebJobsVs Visual Studio extension.

As a side note: some of my colleagues at Readify have recently started using Web Jobs as a platform for deploying Microservices in asynchronous messaging based systems. It’s actually quite a nice combination because you can put any configuration / management / monitoring information associated with the micro-service in the web site portion of the deployment and it’s intrinsically linked to the Web Job in both the source code and the deployment.

Worker Roles

If you are in a situation where you have an intense workload, you need to scale the workload independently  of your Web Sites instances or your workload isn’t supported by the Azure Web Sites platform (and thus can be run as a Web Job) then you need to start looking at Worker Roles or some other form of background processing.

Treat Worker Roles as infrastructure

One thing that I’ve been trying to push for a number of years now (particularly via my AzureWebFarm and AzureWebFarm.OctopusDeploy projects) is for people to think of Cloud Services deployments as infrastructure rather than applications.

With that mindset shift, Cloud Services becomes amazing rather than a deployment pain:

  • Within 8-15+ minutes a number of customised, RDP-accessible, Virtual Machines are being provisioned for you on a static IP address and those machines can be scaled up or down at any time and they have health monitoring and diagnostics capabilities built-in as well as a powerful load balancer and ability to arbitrarily install software or perform configurations with elevated privileges!
  • To reiterate: waiting 8-15+ minutes for a VM to be provisioned is amazing; waiting 8-15+ minutes for the latest version of your software application to be deployed is unacceptably slow!

By treating Cloud Services as stateless, scalable infrastructure you will rarely perform deployments and the deployment time is then a non-issue – you will only perform deployments when scaling up or rolling out infrastructure updates (which should be a rare event and if it rolls out seamlessly then it doesn’t matter how long it takes).

Advantages of Web/Worker Roles as infrastructure

  • As above, slow deployments don’t matter since they are rare events that should be able to happen seamlessly without taking out the applications hosted on them.
  • As above, you can use all of the capabilities available in Cloud Services.
  • Your applications don’t have to have a separate Azure project in them making the Visual Studio solution simpler / load faster etc.
  • Your applications don’t have any Azure-specific code in them (e.g. CloudConfiguationManager, RoleEnvironment, RoleEntryPoint, etc.) anymore
    • This makes your apps simpler and also means that you aren’t coding anything in them that indicates how/where they should be deployed – this is important and how it should be!
    • It also means you can deploy the same code on-premise and in Azure seamlessly and easily

How do I deploy a background processing workload to Worker Role as infrastructure?

So how does this work you might ask? Well, apart from rolling your own code in the Worker Role to detect, deploy and run your application(s) (say, from blob storage) you have two main options that I know of (both of which are open source projects I own along with Matt Davies):

  • AzureWebFarm and its background worker functionality
    • This would see you deploying the background work as part of MSDeploying a web application and it works quite similar to (but admittedly probably less robust than) Web Jobs – this is suitable for light workloads
  • AzureWebFarm.OctopusDeploy and using OctopusDeploy to deploy a Windows Service
    • In general I recommend using Topshelf to develop Windows Services because it allows a nicer development experience (single console app project that you can F5) and deployment experience (you pass an install argument to install it)
    • You should be able to deploy heavyweight workloads using this approach (just make sure your role size is suitable)

The thing to note about both of these approaches is that you are actually using Web Roles, not Worker Roles! This is fine because there isn’t actually any difference between them apart from the fact that Web Roles have IIS installed and configured. If you don’t want anyone to access the servers over HTTP because they are only used for background processing then simply don’t expose a public endpoint.

So, when should I actually use Worker Roles (aka you said they aren’t applicable 99% of the time – what about the other 1%)?

OK, so there is definitely some situations I can think of and have come across before occasionally that warrant the application actually being coded as a Worker Role – remember to be pragmmatic and use the right tool for the job! Here are some examples (but it’s by no means exhaustive):

  • You need the role to restart if there are any uncaught exceptions
  • You need the ability to control the server as part of the processing – e.g. request the server start / stop
  • You want to connect to internal endpoints in a cloud service deployment or do other complex things that require you to use RoleEnvironment
  • There isn’t really an application-component (or it’s tiny) – e.g. you need to install a custom application when the role starts up and then you invoke that application in some way

What about Virtual Machines?

Sometimes Cloud Services aren’t going to work either – in a scenario where you need persistent storage and can’t code your background processing code to be stateless via RoleEntryPoint then you might need to consider standing up one or more Virtual Machines. If you can avoid this at all then I highly recommend it since you then need to maintain the VMs rather than using a managed service.

Other workloads

This post is targeted at the types of background processing workloads you would likely deploy to a Worker Role. There are other background processing technologies in Azure that I have deliberately not covered in this post such as Hadoop.

GitVersion TeamCity MetaRunner

I’ve blogged previously about using GitHubFlowVersion for versioning and how I created a TeamCity meta-runner for it.

A lot has happened since then in that space and that has been nicely summarised by my friend Jake Ginnivan. tl;dr GitHubFlow version has been merged with the GitFlowVersion project to form GitVersion.

This project is totally awesome and I highly recommend that you use it. In short:

GitVersion uses your git repository branching conventions to determine the current Semantic Version of your application. It supports GitFlow and the much simpler GitHubFlow.

I’ve gone ahead and developed a much more comprehensive TeamCity meta-runner for GitVersion and I’ve submitted it to the TeamCity meta-runner PowerPack. This meta-runner allows you to use GitVersion without needing to install any binaries on your build server or your source repository – it automatically downloads it from Chocolatey :)

Happy building!

Announcing 1.0.0 of ReliableDbProvider library

I’d like to announce that today I’ve released v1.0.0 of the ReliableDbProvider library. It’s been kicking around for a while, has a reasonable number of downloads on NuGet and has just received a number of bug fixes from the community so I feel it’s ready for the 1.0.0 badge :).

ReliableDbProvider is a library that allows you to unobtrusively handle transient errors when connecting to Azure SQL Database when using ADO.NET, Linq 2 Sql, EntityFramework < 6 (EF6 has similar functionality in-built) or any library that uses ADO.NET (e.g. Massive).

Check it out on GitHub.

Authenticating an ASP.NET MVC 5 application with Microsoft Azure Active Directory

This post outlines how to easily add Azure AD authentication to an existing (or new) ASP.NET MVC 5 (or 3 or 4) application.

Practical Microsoft Azure Active Directory Blog Series

This post is part of the Practical Microsoft Azure Active Directory Blog Series.

Add Azure AD Authentication

These instructions will help you easily add authentication to your new or existing ASP.NET application, based on what the Visual Studio Identity and Access tools do. It’s a basic setup for a single tenant. Read the next post in the series to understand what’s going on and ways that it can be extended. The links show either a commit from the example project or to relevant documentation.

Note: Ignore the ...‘s and replace the {SPECIFIED_VALUES} with the correct values.

  1. Create an Azure Active Directory tenant; note: AD tenants are not associated with your Azure Subscription, they are “floating” so add any live ids for people you want to administer it as Global Administrators
  2. Create an Application in your AD tenant with audience URL and realm being your website homepage (minus the slash at the end)
    • Record the name of your AD tenant e.g. {name}.onmicrosoft.com
    • Record the GUID of your AD tenant by looking at the FEDERATION METADATA DOCUMENT URL under View Endpoints
    • The image upload and Sign On URL are used for the Azure AD Applications Portal
  3. Create a user account in your tenant that you can use to log in with
  4. Install-Package Microsoft.Owin.Security.ActiveDirectory
  5. Install-Package System.IdentityModel.Tokens.ValidatingIssuerNameRegistry
  6. Add a reference to System.IdentityModel
  7. Add a reference to System.IdentityModel.Services
  8. Add a Startup.cs file (if it doesn’t already exist) and configure OWIN to use Azure Active Directory (edit for new version)
    using System.Configuration;
    using Microsoft.Owin.Security.ActiveDirectory;
    using Owin;
    
    namespace {YOUR_NAMESPACE}
    {
        public class Startup
        {
            public void Configuration(IAppBuilder app)
            {
                app.UseWindowsAzureActiveDirectoryBearerAuthentication(
                    new WindowsAzureActiveDirectoryBearerAuthenticationOptions
                    {
                        TokenValidationParameters = new TokenValidationParameters
                        {
                            ValidAudience = ConfigurationManager.AppSettings["ida:AudienceUri"]
                        },
                        Tenant = ConfigurationManager.AppSettings["AzureADTenant"]
                    });
            }
        }
    }
    
  9. Add the correct configuration to your web.config file; change requireSsl and requireHttps to true if using a https:// site (absolutely required for production scenarios)
    <?xml version="1.0" encoding="utf-8"?>
    <configuration>
      <configSections>
        <section name="system.identityModel" type="System.IdentityModel.Configuration.SystemIdentityModelSection, System.IdentityModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
        <section name="system.identityModel.services" type="System.IdentityModel.Services.Configuration.SystemIdentityModelServicesSection, System.IdentityModel.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
      </configSections>
    ...
      <appSettings>
        ...
        <add key="ida:AudienceUri" value="{YOUR_WEBSITE_HOMEPAGE_WITHOUT_TRAILING_SLASH}" />
        <add key="ida:FederationMetadataLocation" value="https://login.windows.net/{YOUR_AD_TENANT_NAME}.onmicrosoft.com/FederationMetadata/2007-06/FederationMetadata.xml" />
        <add key="AzureADTenant" value="{YOUR_AD_TENANT_NAME}.onmicrosoft.com" />
      </appSettings>
    ...
      <system.webServer>
        ...
        <modules>
          <add name="WSFederationAuthenticationModule" type="System.IdentityModel.Services.WSFederationAuthenticationModule, System.IdentityModel.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" preCondition="managedHandler" />
          <add name="SessionAuthenticationModule" type="System.IdentityModel.Services.SessionAuthenticationModule, System.IdentityModel.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" preCondition="managedHandler" />
        </modules>
      </system.webServer>
    ...
      <system.identityModel>
        <identityConfiguration>
          <issuerNameRegistry type="System.IdentityModel.Tokens.ValidatingIssuerNameRegistry, System.IdentityModel.Tokens.ValidatingIssuerNameRegistry">
            <authority name="https://sts.windows.net/{YOUR_AD_TENANT_GUID}/">
              <keys>
                <add thumbprint="0000000000000000000000000000000000000000" />
              </keys>
              <validIssuers>
                <add name="https://sts.windows.net/{YOUR_AD_TENANT_GUID}/" />
              </validIssuers>
            </authority>
          </issuerNameRegistry>
          <audienceUris>
            <add value="{YOUR_WEBSITE_HOMEPAGE_WITHOUT_TRAILING_SLASH}" />
          </audienceUris>
          <securityTokenHandlers>
            <add type="System.IdentityModel.Services.Tokens.MachineKeySessionSecurityTokenHandler, System.IdentityModel.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
            <remove type="System.IdentityModel.Tokens.SessionSecurityTokenHandler, System.IdentityModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
          </securityTokenHandlers>
          <certificateValidation certificateValidationMode="None" />
        </identityConfiguration>
      </system.identityModel>
      <system.identityModel.services>
        <federationConfiguration>
          <cookieHandler requireSsl="false" />
          <wsFederation passiveRedirectEnabled="true" issuer="https://login.windows.net/{YOUR_AD_TENANT_NAME}.onmicrosoft.com/wsfed" realm="{YOUR_WEBSITE_HOMEPAGE_WITHOUT_TRAILING_SLASH}" requireHttps="false" />
        </federationConfiguration>
      </system.identityModel.services>
    </configuration>
    
  10. Configure AntiForgery to use the correct claim type to uniquely identify users
    Global.asax.cs
    
              protected void Application_Start()
              {
                  ...
                  IdentityConfig.ConfigureIdentity();
              }
    
    App_Start\IdentityConfig.cs
    
    using System.IdentityModel.Claims;
    using System.Web.Helpers;
    
    namespace {YOUR_NAMESPACE}
    {
        public static class IdentityConfig
        {
            public static void ConfigureIdentity()
            {
                AntiForgeryConfig.UniqueClaimTypeIdentifier = ClaimTypes.Name;
            }
        }
    }
    
  11. Configure the application to refresh issuer keys when they change
            public static void ConfigureIdentity()
            {
                ...
                RefreshIssuerKeys();
            }
    
            private static void RefreshIssuerKeys()
            {
                // http://msdn.microsoft.com/en-us/library/azure/dn641920.aspx
                var configPath = AppDomain.CurrentDomain.BaseDirectory + "\\" + "Web.config";
                var metadataAddress = ConfigurationManager.AppSettings["ida:FederationMetadataLocation"];
                ValidatingIssuerNameRegistry.WriteToConfig(metadataAddress, configPath);
            }
    
  12. Add LogoutController
    Controllers\LogoutController.cs
    
    using System;
    using System.IdentityModel.Services;
    using System.Web.Mvc;
    
    namespace {YOUR_NAMESPACE}.Controllers
    {
        public class LogoutController : Controller
        {
            public ActionResult Index()
            {
                var config = FederatedAuthentication.FederationConfiguration.WsFederationConfiguration;
    
                var callbackUrl = Url.Action("Callback", "Logout", null, Request.Url.Scheme);
                var signoutMessage = new SignOutRequestMessage(new Uri(config.Issuer), callbackUrl);
                signoutMessage.SetParameter("wtrealm", config.Realm);
                FederatedAuthentication.SessionAuthenticationModule.SignOut();
    
                return new RedirectResult(signoutMessage.WriteQueryString());
            }
    
            [AllowAnonymous]
            public ActionResult Callback()
            {
                if (Request.IsAuthenticated)
                    return RedirectToAction("Index", "Home");
    
                return View();
            }
        }
    }
    
    Views\Logout\Callback.cshtml
    
    @{
        ViewBag.Title = "Logged out";
    }
    
    <h1>Logged out</h1>
    
    <p>You have successfully logged out of this site. @Html.ActionLink("Log back in", "Index", "Home").</p>
    
  13. Add logout link somewhere@Html.ActionLink("Logout", "Index", "Logout")
  14. Add authentication to the app; do this as you normally would with [Authorize] to specific controller(s) or action(s) or globally by adding to GlobalFilters.Filters.Add(new AuthorizeAttribute());
  15. Load the site and navigate to one of the authenticated pages – it should redirect you to your Azure AD tenant login page whereupon you need to log in as one of the users you created and it should take you back to that page, logged in
  16. The usual User.Identity.Name and User.Identity.IsAuthenticated objects should be populated and if you want access to the claims to get the user’s name etc. then use something like ClaimsPrincipal.Current.FindFirst(ClaimTypes.GivenName).Value

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