Monday, 17 September 2012
Using TFS with the WorkflowCentralLogger, PowerShell and PSAKE

I was recently brought into a client site where they had made use of PSAKE to handle their build process. The build would be kicked off from the traditional Workflow in TFS using an Invoke Process. Everything was working perfectly until they spotted that when the build failed there was no way of viewing which unit tests had failed from within TFS. In short PowerShell was giving precious little to the TFS summary view.

The question was how could we get that rich logging information you got in the build summary when doing a traditional build using Workflow? Setting up a traditional build and observing how MSBUILD is called from TFS starts to shed some light on the situation

C:\Windows\Microsoft.NET\Framework64\v4.0.30319\MSBuild.exe /nologo /noconsolelogger "C:\Builds\1\Scratch\Test Build\Sources\user\Test\Build.proj" /m:1 /fl /p:SkipInvalidConfigurations=true  /p:OutDir="C:\Builds\1\Scratch\Test Build\Binaries\\" /p:VCBuildOverride="C:\Builds\1\Scratch\Test Build\Sources\user\Test\Build.proj.vsprops" /dl:WorkflowCentralLogger,"C:\Program Files\Microsoft Team Foundation Server 2010\Tools\Microsoft.TeamFoundation.Build.Server.Logger.dll";"Verbosity=Normal;BuildUri=vstfs:///Build/Build/111;InformationNodeId=6570;
http://mytfshost:8080/tfs/Test%20Collection;"*WorkflowForwardingLogger,"C:\Program Files\Microsoft Team Foundation Server 2010\Tools\Microsoft.TeamFoundation.Build.Server.Logger.dll";"Verbosity=Normal;"


In the above example I have highlighted the section I discovered is responsible for the summary view you usually see when kicking off a build from TFS. I discovered this with a bit of guesswork and some reflector usage to see what was going on inside MSBUILD. Googling for the WorkflowCentralLogger gives precious little back about how it works and more about the errors people have encountered with it.

Getting to the solution
You will be forgiven for thinking the answer to the problem is just adding the missing WorkflowCentralLogger switch (with arguments) to your MSBUILD command line in PowerShell/PSAKE. Sadly its not that simple. See the InformationNodeId in the above command line? This appears to tell the WorkFlowCentralLogger where it needs to append its logging information. Passing it into the Invoke Process was my first thought, the problem is you're not going to find anything that will give it to you, I wasn't able to find it anywhere.

So how do you get it to work then?
The answer is, you need to build a Custom Workflow Activity. A custom workflow activity will have access to the current Context. To use this you need to inherit the class "CodeActivity". Its up to you how you use this Custom Workflow Activity, you have one of two ways.

  • Place it above the Invoke Process in your workflow, get the InformationNodeId and pass this as an OutArgument to the Invoke Process below it (not tested fully)
  • Or invoke Powershell from within the Custom Activity using a runspace and pass it the code context. (fully tested)
   3:  namespace MyWorkflowActivities
   4:  {
   5:      using System;
   6:      using System.Collections.Generic;
   7:      using System.Linq;
   8:      using System.Text;
   9:      using System.Collections.ObjectModel;
  10:      using System.Management.Automation;
  11:      using System.Management.Automation.Runspaces;
  12:      using System.IO;
  13:      using System.Activities;
  14:      using System.Collections;
  15:      using System.Globalization;
  17:      using Microsoft.TeamFoundation.Build.Client;
  18:      using Microsoft.TeamFoundation.Build.Workflow.Activities;
  19:      using Microsoft.TeamFoundation.Build.Workflow.Services;
  21:      public OutArgument<string> InformationNodeIdOut { get; set; }
  23:      [BuildActivity(HostEnvironmentOption.All)]
  24:      public sealed class GetInformationNodeId : CodeActivity
  25:      {
  26:          protected override void Execute(CodeActivityContext context)
  27:          {
  29:              context.TrackBuildMessage("Getting the Information Node Id", BuildMessageImportance.Low);
  30:              IActivityTracking activityTracking = context.GetExtension<IBuildLoggingExtension>().GetActivityTracking((ActivityContext) context);
  31:              string informationNodeId = activityTracking.Node.Id.ToString("D", (IFormatProvider)CultureInfo.InvariantCulture);
  33:              context.SetValue<string>(this.InformationNodeIdOut, informationNodeId);
  34:          }
  35:      }
  37:  }

The code above illustrates the first solution. Its a lot simpler and you'll have to pass that node id to MSBUILD when you construct its command line in PowerShell. Line 30 and 31 is where all the magic takes place, I managed to find this line using reflector in MSBUILD. If you have never written a custom activity before Ewald Hofman has a short summary of one here

The diagram below illustrates where GetInformationNodeId (code above) sits just above the InvokeProcess which calls PowerShell.



The second solution, which I actually went with is slightly more complex and I'll blog about how I did that in another article. You might be wondering what are the immediate benefits of one over the other? The beauty of going with the second solution is you can make use of the code activity context within your PowerShell scripts. So for example instead of writing your PowerShell events out to the host you could wrap that call in context.TrackBuildMessage (as illustrated on line 29 above). Hopefully I'll find some time to blog about that next week!

I'd be interested to hear about other peoples experiences.

posted on Monday, 17 September 2012 14:19:34 (GMT Standard Time, UTC+00:00)  #    Comments [0]