Passing a PowerShell Array back to TFS build Template

Question

I pieced together a pipeline that returns a list of files and their paths if said files match prescribed patterns:

Param ($dropDir)

$MatchingScripts = Get-ChildItem $dropDir\*.sql -Recurse 
    | Select-String -pattern \*ONEFISH\*,\*TWOFISH\*,\*REDFISH\* 
    | group path 
    | Foreach-Object {$_.Name} 
    | Out-File D:\logging\scrubfiles.log

return $MatchingScripts

So there's one param in there where I feed in the dynamically-named drop path every time and search down that path. The goal then is to return $MatchingScripts array to the build template and throw the array into a ForEach<string> loop that will InvokeProcess on a custom tool which will scrub each \path\file\ and replace said token value patterns.

Problem: I can't get that array from PowerShell fed back to the team build. I've tried containing the script in a .ps1 along with a closing return $MatchingScripts ...but nothing is reaching the pre-defined IEnumerable<String> by the same name 'MatchingScripts' in the build template.

I'm still trying to make the TFSBuildExtensions InvokePowerShellCommand activity to do this for me, as well, but the problem there is a conversion of types that have to be overcome (PSOBject to Array of Strings).

They key bit is that tool I have to send this array through needs to consist of strings.

Answer 1

If it were me I'd just loop through and call your custom tool directly from PowerShell, rather than trying to pass data back to WF and doing it from there.

Answer 2

Here's the work-around we used to return value:

Since what we piped out to log was clean (just files & paths), we read the log back into an array of strings via the Assign activity using a VB expression...

MatchingScripts = File.ReadAllLines("D:\logging\scrubfiles_" + BuildDetail.BuildNumber.ToString() + ".txt")

There's a little concatenation there because we later chose to individualize the each log according to the 'build' it ran under. Anyway, it worked a treat!

Moral of the story: understand that if you want to return ANYTHING other than an integer value from PowerShell/InvokeProcess, be prepared to write/find a custom activity or come up with some other work-around that can feed directly back into Workflow.