Error trying to publish and deploy AspNet 5 project to Azure

[gthuruv]

I am trying to create a build definition in VS 2015 to perform build, publish and deploy process. I followed the instructions from this page. https://msdn.microsoft.com/en-us/Library/vs/alm/Build/azure/deploy-aspnet5

I tried out the msbuild locally via command line and everything worked fine (After writing a script to manually "dnu build" all the VS 2013 referred projects under the wrap folder because msbuild publish is not doing it). When I created a build definition and queued it to run on the build machine though it is failing with the following error.

C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v14.0\DNX\Microsoft.DNX.targets (158, 0)
events.js:141
C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v14.0\DNX\Microsoft.DNX.targets (158, 0)
throw er; // Unhandled 'error' event
C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v14.0\DNX\Microsoft.DNX.targets (158, 0)
^
DNX (0, 0)
EPERM: operation not permitted, open 'C:\wwwroot\js\site.min.js'
C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v14.0\DNX\Microsoft.DNX.targets (158, 0)
at Error (native)
C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v14.0\DNX\Microsoft.DNX.targets (158, 0)
The 'prebuild' script failed with status code 1.

The prebuild script is failing. I am trying to run gulp tasks during the pre-build process, which does some file manipulations.

Also, is msbuild the way to go or is there a better way to directly run "dnu build" on the build machines?