Can I invoke gulp from a cake-build file? - asp.net

Question

I have an ASP.NET solution where I perform some tasks using gulp (e.g. less-compilation). Inside Visual Studio the corresponding gulp-task is bound to the BeforeBuild event, so it is automatically started whenever I build the solution.
I was experimenting with cake for building and packaging the solution. While building the solution works fine using either the DotNetBuild() or MSBuild() tasks, the gulp tasks are not executed during the build.
It seems that gulp (and probably also other task runners) are not automatically "integrated" in the build process.
Does cake somehow support invoking gulp during the build?
(Of course, it should ideally also restore gulp itself (using npm / package.json) if it is not available.)

Answer 1

Note: This answer was copied from the
Cake issue response
by Mattias Karlsson (with his permission).
Just did a quick look so I might be missing something, but checking the
csproj file, the BeforeBuild MSBuild target seems to be empty?
Visual Studio 2015 has a built-in task runner for Gulp/Grunt so this
might be what's kicking in.
Currently we don't have aliases for NPM or Gulp (that would be an
great addin though), but what you could do is to invoke Gulp yourself
via the StartProcess alias. I tweaked your build.cake slighly below:
var target = Argument("target", "Default");
DirectoryPath solutionDir = MakeAbsolute(Directory("./"));
FilePath solution = solutionDir.CombineWithFilePath("WebApplication1.sln");
DirectoryPath projectDir = solutionDir.Combine("WebApplication1");
FilePath lessOutput = projectDir.CombineWithFilePath("css/style.css");
Task("Default")
.Does(() =>
{
NuGetRestore(solution);
if (FileExists(lessOutput))
{
Information("Cleaning old less output {0}", lessOutput);
DeleteFile(lessOutput);
}
StartProcess("cmd", new ProcessSettings {
Arguments = "/c \"set CI=true && npm install && gulp compile-less\"",
WorkingDirectory = projectDir
});
if (!FileExists(lessOutput))
{
throw new Exception("Less failed to create " + lessOutput);
}
Information("Less created {0}", lessOutput);
MSBuild(solution);
});
RunTarget(target);
This assumes you have Node & Gulp installed globally (you install Gulp
globally via running npm install -g gulp), also this was 5 min quick
and dirty, so you would want to divide clean/restore/less into separate
cake tasks. I set environment CI=true because some node modules
could require user interaction on restore otherwise.
Discarding MSBuild / NuGet restore above will output something like:
Cleaning old less output C:/temp/cake_issue_672/WebApplication1/WebApplication1/css/style.css
[11:26:12] Using gulpfile C:\temp\cake_issue_672\WebApplication1\WebApplication1\gulpfile.js
[11:26:12] Starting 'compile-less'...
[11:26:13] Finished 'compile-less' after 29 ms
Less created C:/temp/cake_issue_672/WebApplication1/WebApplication1/css/style.css
This might not be the solution you were working for, but it "should"
work.

Answer 2

UPDATE: There is now an addin for Cake for running Gulp Tasks. You can find it here
As to why using the MSBuild Alias in Cake is not invoking the BeforeBuild target we are not sure. Could I ask that you raise an issue here so that we can discuss it. Ideally, a sample project that demonstrates the problem could be provided so that we can investigate.
To answer your overall question though...
No, currently, there are no Cake Aliases/Addin's that support running Gulp Tasks as part of the build pipeline. That is not to say that this couldn't be done, simply that it hasn't been on our radar yet.
Having said that, given that you can write any arbitrary C# as part of your build script, there is no reason that you couldn't spawn out a process to invoke gulp with the necessary arguments to do the work.