Invoke-Build direct calling bootstrap script (load or install compatible msbuild version, self updating and support different versions in different projects)

project.build.ps1

param (
  [Parameter(Position=0)]
	$Tasks
  #... other params
)

function IsVersionCompatible($requiredVersion, $testVersion) {
  # same major, and AT LEAST the required minor and build
  $testVersion.Major -eq $requiredVersion.Major `
    -and $testVersion.Minor -ge $requiredVersion.Minor `
    -and $testVersion.Build -ge $requiredVersion.Build
}

# Direct call support, calling .\web.build.ps1 bootstraps the InvokeBuild PS module
if ([System.IO.Path]::GetFileName($MyInvocation.ScriptName) -ne 'Invoke-Build.ps1') {
  $ErrorActionPreference = 'Stop'
  
  $requiredVersion = new-object System.Version "5.5.9"
  
  $loadedModule = get-module invokebuild
  $moduleAlreadyLoaded = $loadedModule `
    -and @($loadedModule).Length -eq 1 `
    -and (IsVersionCompatible $requiredVersion $loadedModule.Version)

  if (!$moduleAlreadyLoaded)
  {
    if ($loadedModule) { remove-module invokebuild }
    $availableModule = get-module -ListAvailable invokebuild |
      ?{ IsVersionCompatible $requiredVersion $_.Version } | 
      sort Version -Descending | select -First 1
    if ($availableModule) {
      Write-Host "Importing InvokeBuild $($availableModule.Version)"
      import-module invokebuild -RequiredVersion "$($availableModule.Version)" -Force
    }
    else {
      Write-Host "Did not find a compatible version of the InvokeBuild Module, installing $requiredVersion"
      install-module invokebuild -RequiredVersion "$requiredVersion" -Scope CurrentUser -Force
      import-module invokebuild -RequiredVersion "$requiredVersion" -Force
    }
  }
  else {
    Write-Host "Running with InvokeBuild $($loadedModule.Version)"
  }

	Invoke-Build -Task $Tasks @PSBoundParameters
	return
}