Maarten Balliauw {blog}

ASP.NET MVC, Microsoft Azure, PHP, web development ...

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Setting up a NuGet repository in seconds: MyGet public feeds

A few months ago, my colleague Xavier Decoster and I introduced MyGet as a tool where you can create your own, private NuGet feeds. A couple of weeks later we introduced some options to delegate feed privileges to other MyGet users allowing you to make another MyGet user “co-admin” or “contributor” to a feed. Since then we’ve expanded our view on the NuGet ecosystem and moved MyGet from a solution to create your private feeds to a service that allows you to set up a NuGet feed, whether private or public.

Supporting public feeds allows you to set up a structure similar to www.nuget.org: you can give any user privileges to publish a package to your feed while the user can never manage other packages on your feed. This is great in several scenarios:

  • You run an open source project and want people to contribute modules or plugins to your feed
  • You are a business and you want people to contribute internal packages to your feed whilst prohibiting them from updating or deleting other packages

Setting up a public feed

Setting up a public feed on MyGet is similar to setting up a private feed. In fact, both are identical except for the default privileges assigned to users. Navigate to www.myget.org and sign in using an identity provider of choice. Next, create a feed, for example:

Create a MyGet NuGet feed and host your own NuGet packages

This new feed may be named “public”, however it is private by obscurity: if someone knows the URL to the feed, he/she can consume packages from it. Let’s change that. Go to the “Feed Security” tab and have a look at the assigned privileges for Everyone. By default, these are set to “Can consume this feed”, meaning that everyone can add the feed URL to Visual Studio and consume packages. Other options are “No access” (requires authentication prior to being able to consume the feed) and “Can contribute own packages to this feed”. This last one is what we want:

Setting up a NuGet feed

Assigning the “Can contribute own packages to this feed” privilege to a specific user or to everyone means that the user (or everyone) will be able to contribute packages to the feed, as long as the package id used is not already on the feed and as long as the package id was originally submitted by this user. Exactly the same model as www.nuget.org, that is.

For reference, all available privileges are:

  • Has no access to this feed (speaks for itself)
  • Can consume this feed (allows the user to use the feed in Visual Studio / NuGet)
  • Can contribute own packages to this feed '(allows the user to contribute packages but can only update and remove his own packages and not those of others)
  • Can manage all packages for this feed (allows the user to add packages to the feed via the website and via the NuGet push API)
  • Can manage users and all packages for this feed (extends the above with feed privilege management capabilities)

Contributing to a public feed

Of course, if you have a public feed you may want to have people contributing to it. This is very easy: provide them with a link to your feed editing page (for example, http://www.myget.org/Feed/Edit/public). Users can publish their packages via the MyGet user interface in no time.

If you want to have users push packages using nuget.exe or NuGet Package Explorer, provide them a link to the feed endpoint (for example, http://www.myget.org/F/public/). Using their API key (which can be found in the MyGet profile for the user) they can push packages to the public feed from any API consumer.

Enjoy!

 

PS: We’re working on lots more, but will probably provide that in a MyGet Premium version. Make sure to subscribe to our newsletter on www.myget.org if this is of interest.

NuGet push... to Windows Azure

When looking at how people like to deploy their applications to a cloud environment, a large faction seems to prefer being able to use their source control system as a source for their production deployment. While interesting, I see a lot of problems there: your source code may not run immediately and probably has to be compiled. You don’t want to maintain compiled assemblies in source control, right? Also, maybe some QA process is in place where a deployment can only occur after approval. Why not use source control for what it’s there for: source control? And how about using a NuGet repository as the source for our deployment? Meet the Windows Azure NuGetRole.

Disclaimer/Warning: this is demo material and should probably not be used for real-life deployments without making it bullet proof!

Download the sample code: NuGetRole.zip (262.22 kb)

How to use it

If you compile the source code (download), you have X steps left in getting your NuGetRole running on Windows Azure:

  • Specifying the package source to use
  • Add some packages to the package source feed (which you can easily host on MyGet)
  • Deploy to Windows Azure

When all these steps have been taken care of, the NuGetRole will download all latest package versions from the package source specified in ServiceConfiguration.cscfg:

1 <?xml version="1.0" encoding="utf-8"?> 2 <ServiceConfiguration serviceName="NuGetRole.Azure" 3 xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" 4 osFamily="1" 5 osVersion="*"> 6 <Role name="NuGetRole.Web"> 7 <Instances count="1" /> 8 <ConfigurationSettings> 9 <Setting name="Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString" value="UseDevelopmentStorage=true" /> 10 <Setting name="PackageSource" value="http://www.myget.org/F/nugetrole/" /> 11 </ConfigurationSettings> 12 </Role> 13 </ServiceConfiguration>

Packages you publish should only contain a content and/or lib folder. Other package contents will currently be ignored by the NuGetRole. If you want to add some web content like a default page to your role, simply publish the following package:

NuGet Package Explorer MyGet NuGet NuGetRole Azure

Just push, and watch your Windows Azure web role farm update their contents. Or have your build server push a NuGet package containing your application and have your server farm update itself. Whatever pleases you.

How it works

What I did was create a fairly empty Windows Azure project (download).  In this project, one Web role exists. This web role consists of nothing but a Web.config file and a WebRole.cs class which looks like the following:

1 public class WebRole : RoleEntryPoint 2 { 3 private bool _isSynchronizing; 4 private PackageSynchronizer _packageSynchronizer = null; 5 6 public override bool OnStart() 7 { 8 var localPath = Path.Combine(Environment.GetEnvironmentVariable("RdRoleRoot") + "\\approot"); 9 10 _packageSynchronizer = new PackageSynchronizer( 11 new Uri(RoleEnvironment.GetConfigurationSettingValue("PackageSource")), localPath); 12 13 _packageSynchronizer.SynchronizationStarted += sender => _isSynchronizing = true; 14 _packageSynchronizer.SynchronizationCompleted += sender => _isSynchronizing = false; 15 16 RoleEnvironment.StatusCheck += (sender, args) => 17 { 18 if (_isSynchronizing) 19 { 20 args.SetBusy(); 21 } 22 }; 23 24 return base.OnStart(); 25 } 26 27 public override void Run() 28 { 29 _packageSynchronizer.SynchronizeForever(TimeSpan.FromSeconds(30)); 30 31 base.Run(); 32 } 33 }

The above code is essentially wiring some configuration values like the local web root and the NuGet package source to use to a second class in this project: the PackageSynchronizer. This class simply checks the specified NuGet package source every few minutes, checks for the latest package versions and if required, updates content and bin files.  Each synchronization run does the following:

1 public void SynchronizeOnce() 2 { 3 var packages = _packageRepository.GetPackages() 4 .Where(p => p.IsLatestVersion == true).ToList(); 5 6 var touchedFiles = new List<string>(); 7 8 // Deploy new content 9 foreach (var package in packages) 10 { 11 var packageHash = package.GetHash(); 12 var packageFiles = package.GetFiles(); 13 foreach (var packageFile in packageFiles) 14 { 15 // Keep filename 16 var packageFileName = packageFile.Path.Replace("content\\", "").Replace("lib\\", "bin\\"); 17 18 // Mark file as touched 19 touchedFiles.Add(packageFileName); 20 21 // Do not overwrite content that has not been updated 22 if (!_packageFileHash.ContainsKey(packageFileName) || _packageFileHash[packageFileName] != packageHash) 23 { 24 _packageFileHash[packageFileName] = packageHash; 25 26 Deploy(packageFile.GetStream(), packageFileName); 27 } 28 } 29 30 // Remove obsolete content 31 var obsoleteFiles = _packageFileHash.Keys.Except(touchedFiles).ToList(); 32 foreach (var obsoletePath in obsoleteFiles) 33 { 34 _packageFileHash.Remove(obsoletePath); 35 Undeploy(obsoletePath); 36 } 37 } 38 }

Or in human language:

  • The specified NuGet package source is checked for packages
  • Every package marked “IsLatest” is being downloaded and deployed onto the machine
  • Files that have not been used in the current synchronization step are deleted

This is probably not a bullet-proof solution, but I wanted to show you how easy it is to use NuGet not only as a package manager inside Visual Studio, but also from your code: NuGet is not just a package manager but in essence a package management protocol. Which you can easily extend.

One thing to note: I also made the Windows Azure load balancer ignore the role that’s updating itself. This means a roie instance that is synchronizing its contents will never be available in the load balancing pool so no traffic is sent to the role instance during an update.

ASP.NET MVC dynamic view sections

Earlier today, a colleague of mine asked for advice on how he could create a “dynamic” view. To elaborate, he wanted to create a change settings page on which various sections would be rendered based on which plugins are loaded in the application.

Intrigued by the question and having no clue on how to do this, I quickly hacked together a SettingsViewModel, to which he could add all section view models no matter what type they are:

1 public class SettingsViewModel 2 { 3 public List<dynamic> SettingsSections = new List<dynamic>(); 4 }

To my surprise, when looping this collection in the view it just works as expected: every section is rendered using its own DisplayTemplate. Simple and slick.

1 @model MvcApplication.ViewModels.SettingsViewModel 2 3 @{ 4 ViewBag.Title = "Index"; 5 } 6 7 <h2>Settings</h2> 8 9 @foreach (var item in Model.SettingsSections) 10 { 11 @Html.DisplayFor(model => item); 12 }

Why MyGet uses Windows Azure

MyGet - NuGet hosting private feedRecently one of the Tweeps following me started fooling around and hit one of my sweet spots: Windows Azure. Basically, he mocked me for using Windows Azure for MyGet, a website with enough users but not enough to justify the “scalability” aspect he thought Windows Azure was offering. Since Windows Azure is much, much more than scalability alone, I decided to do a quick writeup about the various reasons on why we use Windows Azure for MyGet. And those are not scalability.

First of all, here’s a high-level overview of our deployment, which may illustrate some of the aspects below:

image

Costs

Windows Azure is cheap. Cheap as in cost-effective, not as in, well, sleezy. Many will disagree with me but the cost perspective of Windows Azure can be real cheap in some cases as well as very expensive in other cases. For example, if someone asks me if they should move to Windows Azure and they now have one server running 300 small sites, I’d probably tell them not to move as it will be a tough price comparison.

With MyGet we run 2 Windows Azure instances in 2 datacenters across the globe (one in the US and one in the EU). For $180.00 per month this means 2 great machines at two very distant regions of the globe. You can probably find those with other hosters as well, but will they manage your machines? Patch and update them? Probably not, for that amount. In our scenario, Windows Azure is cheap.

Feel free to look at the cost calculator tool to estimate usage costs.

Traffic Manager

Traffic Manager, a great (beta) product in the Windows Azure offering allows us to do geographically distributed applications. For example, US users of MyGet will end up in the US datacenter, European users will end up in the EU datacenter. This is great, and we can easily add extra locations to this policy and have, for example, a third location in Asia.

Next to geographically distributing MyGet, Traffic Manager also ensures that if one datacenter goes down, the DNS pool will consist of only “live” datacenters and thus provide datacenter fail-over. Not ideal as the web application will be served faster from a server that’s closer to the end user, but the application will not go down.

One problem we have with this is storage. We use Windows Azure storage (blobs, tables and queues) as those only cost $0.12 per GB. Distributing the application does mean that our US datacenter server has to access storage in the EU datacenter which of course adds some latency. We try to reduce this using extensive caching on all sides, but it’d be nicer if Traffic Manager allowed us to setup georeplication for storage as well. This only affects storing package metadata and packages. Reading packages is not affected by this because we’re using the Windows Azure CDN for that.

CDN

The Windows Azure Content Delivery Network allows us to serve users fast. The main use case for MyGet is accessing and downloading packages. Ok, the updating has some latency due to the restrictions mentioned above, but if you download a package from MyGet it will always come from a CDN node near the end user to ensure low latency and fast access. Given the CDN is just a checkbox on the management pages means integrating with CDN is a breeze. The only thing we’ve struggled with is finding an acceptable caching policy to ensure stale data is limited.

Windows Azure AppFabric Access Control

MyGet is not one application. MyGet is three applications: our development environment, staging and production. In fact, we even plan for tenants so every tenant in fact is its own application. To streamline, manage and maintain a clear overview of which user can authenticate to which application via which identity provider, we use ACS to facilitate MyGet authentication.

To give you an example: our dev environment allows logging in via OpenID on a development machine. Production allows for OpenID on a live environment. In staging, we only use Windows Live ID and Facebook whereas our production website uses different identity providers. Tenants will, in the future, be given the option to authenticate to their own ADFS server, we’re pretty sure ACS will allow us to simply configure that and instrument only tenant X can use that ADFS server.

ACs has been a great time saver and is definitely something we want to use in future project. It really eases common authentication pains and acts as a service bus between users, identity providers and our applications.

Windows Azure AppFabric Caching

Currently we don’t use Windows Azure AppFabric Caching in our application. We currently use the ASP.NET in-memory cache on all machines but do feel the need for having a distributed caching solution. While appealing, we think about deploying Memcached in our application because of the cost structure involved. But we might as well end up with Wndows Azure AppFabric Caching anyway as it integrates nicely with our current codebase.

Conclusion

In short, Windows Azure is much more than hosting and scalability. It’s the building blocks available such as Traffic Manager, CDN and Access Control Service that make our lives easier. The pricing structure is not always that transparent but if you dig a little into it you’ll find affordable solutions that are really easy to use because you don’t have to roll your own.