Run a Windows Azure cloud service locally without the Azure compute emulator

A big bugbear when developing Azure cloud services is the Azure emulator. You make a code change and the write – compile – debug process is slowed down big time because you have to wait for the Azure emulator to start up every time.

One project I worked on had a Web API running in an Azure cloud service and an ASP.NET MVC website running in another cloud service. So in order to develop it locally we had to run 2 instances of Visual Studio 2013 and each of them would fire up an emulator. Needless to say this was quite the resource hog and we’d every now and then see unexpected issues with Visual Studio or the emulators. Oh and the emulators would fight over which ports they would run on so we had to ensure we started debugging the API first so that it would get port 443 and then start the website which would default to 445.

So why can’t we just install our Web API and ASP.NET MVC website into IIS and not use the emulators? Well there are two blockers:

  1. The Azure diagnostics config will throw exceptions if we’re not running in Azure
  2. Settings are read from cloud config values in ServiceConfiguration.cscfg via RoleEnvironment.GetConfigurationSettingValue which needs Azure

My colleague Dylan came up with a solution. Basically, in the Global.asax.cs of both our website and our web api, we need to check if we’re running in Azure or not.

If we are in Azure, then use 1. configure Azure diagnostics config, and 2. read cloud config values using the default RoleEnvironment.GetConfigurationSettingValue.

If we are not in Azure, then 1. don’t configure Azure diagnostics, and 2. read cloud config values from ServiceConfiguration.cscfg manually via XML. parsing.


if (RoleEnvironment.IsAvailable) // we are in Azure
{
    Trace.Listeners.Add(new DiagnosticMonitorTraceListener());
    Trace.AutoFlush = true;
}
else
{
    var di = new DirectoryInfo(HttpContext.Current.Server.MapPath("~"));
    var solutionRoot = di.Parent;

    var xdoc = XDocument.Load(solutionRoot.FullName + @"\Identity.Web.Azure\ServiceConfiguration.cscfg");
    ConfigurationSettingsProvider.Current = new NotInRoleEnvirovmentConfigurationProvider(xdoc, "Identity.Web");
}

Our ConfigurationSettingsProvider.Current is by default a DefaultConfigurationSettingsProvider which uses RoleEnvironment.GetConfigurationSettingValue(key) to read the cloud config – we use one of these when we’re in Azure.

Our NotInRoleEnvirovmentConfigurationProvider reads the .cscfg file using XDocument.

So now I can install our website and web api into IIS locally – and code changes are visible after a compile. No need to run 2 Visual Studios and wait for the memory hungry emulator to startup every time. If I need to debug I can Debug -> Attach to process. Much more productive :-)

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s