application-workloads/visualstudio/vm-vsts-agent/DeployVSTSAgent.config.ps1

<#

.DESCRIPTION
  The DSC will configure a VSTS agent on a VM using Windows PowerShell DSC. 

.NOTES
  Version:        1.0
  Author:         Sampanna Mohite / Nazakat Hussain
  Creation Date:  12/03/2018
  Purpose/Change: Automated Deployments of VSTS Agents
#>


Configuration DeployVSTSAgent
{
  param (
    [Parameter(Mandatory=$false)]
    [string]$MachineName,

    [Parameter(Mandatory=$true)]
    [string]$UserName,

    [Parameter(Mandatory=$true)]
    [string]$Password,

    [Parameter(Mandatory=$false)]
    [string]$VSTSAccount,

    [Parameter(Mandatory=$true)]
    [string]$PersonalAccessToken,

    [Parameter(Mandatory=$true)]
    [string]$AgentName,

    [Parameter(Mandatory=$true)]
    [string]$PoolName,

    [Parameter(Mandatory=$true)]
    [int]$AgentCount,

    [Parameter(Mandatory=$true)]
    [string[]]$Modules
  )
  
  Import-DscResource -ModuleName PsDesiredStateConfiguration

  Node ($MachineName)
  {
    Script SetVstsAgents{
        GetScript = {@{
            Result = ""
        }}

        TestScript = {
            $false
        }
        SetScript ={
            
            #md c:\TestFolder01

            Write-Verbose "VSTSAccounbt - $using:VSTSAccount" -verbose
            Write-Verbose "Token" -verbose
            Write-Verbose "Agent count - $using:AgentCount" -verbose
            Write-Verbose "Entering DeployVSTSAgent.config.ps1" -verbose

            #$currentLocation = Split-Path -parent $MyInvocation.MyCommand.Definition
            #Write-Verbose "Current folder: $currentLocation" -verbose

            #Create a temporary directory where to download from VSTS the agent package (vsts-agent.zip) and then launch the configuration.
            $agentTempFolderName = Join-Path $env:temp ([System.IO.Path]::GetRandomFileName()).replace('.','')
            New-Item -ItemType Directory -Force -Path $agentTempFolderName
            Write-Verbose "Temporary Agent download folder: $agentTempFolderName" -verbose

            $serverUrl = "https://dev.azure.com/$using:VSTSAccount"
            Write-Verbose "Server URL: $serverUrl" -verbose

            $retryCount = 3
            $retries = 1
            
            Write-Verbose "Downloading Agent install files" -verbose
            [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

            do
            {
                try
                {
                    Write-Verbose "Trying to get download URL for latest VSTS agent release..."
                    $latestRelease = Invoke-RestMethod -Uri "https://api.github.com/repos/Microsoft/vsts-agent/releases"
                    $latestRelease = $latestRelease | Where-Object assets -ne $null | Sort-Object created_at -Descending | Select-Object -First 1
                    $assetsURL = ($latestRelease.assets).browser_download_url
                    $latestReleaseDownloadUrl = ((Invoke-RestMethod -Uri $assetsURL) -match 'win-x64').downloadurl
                    Invoke-WebRequest -Uri $latestReleaseDownloadUrl -Method Get -OutFile "$agentTempFolderName\agent.zip"
                    Write-Verbose "Downloaded agent successfully on attempt $retries" -verbose
                    break
                }
                catch
                {
                    $exceptionText = ($_ | Out-String).Trim()
                    Write-Verbose "Exception occurred downloading agent: $exceptionText in try number $retries" -verbose
                    $retries++
                    Start-Sleep -Seconds 30 
                }
            } 
            while ($retries -le $retryCount)

            Write-Verbose "Installing agents $using:AgentCount" -verbose
            Write-Verbose "Installing agents $using:AgentCount" -verbose
            Write-Verbose "VSTSAccounbt - $using:VSTSAccount" -verbose
            Write-Verbose "Token" -verbose
            Write-Verbose "Agent count - $using:AgentCount" -verbose
            Write-Verbose "Entering InstallVSOAgent.ps1" -verbose

            $serverUrl = "https://dev.azure.com/$using:VSTSAccount"
            Write-Verbose "$serverUrl" -verbose

            for ($i=0; $i -lt $using:AgentCount; $i++)
            {
                $Agent = ($using:AgentName + "-" + ($i + 1))
                Write-Verbose "Installing agents $Agent" -verbose

                # Construct the agent folder under the main (hardcoded) C: drive.
                $agentInstallationPath = Join-Path "C:" $Agent

                # Create the directory for this agent.
                New-Item -ItemType Directory -Force -Path $agentInstallationPath

                # Set the current directory to the agent dedicated one previously created.
                Push-Location -Path $agentInstallationPath
                
                Write-Verbose "Extracting the zip file for the agent" -verbose
                $destShellFolder = (new-object -com shell.application).namespace("$agentInstallationPath")
                $destShellFolder.CopyHere((new-object -com shell.application).namespace("$agentTempFolderName\agent.zip").Items(),16)

                # Removing the ZoneIdentifier from files downloaded from the internet so the plugins can be loaded
                # Don't recurse down _work or _diag, those files are not blocked and cause the process to take much longer
                Write-Verbose "Unblocking files" -verbose
                Get-ChildItem -Recurse -Path $agentInstallationPath | Unblock-File | out-null

                # Retrieve the path to the config.cmd file.
                $agentConfigPath = [System.IO.Path]::Combine($agentInstallationPath, 'config.cmd')
                Write-Verbose "Agent Location = $agentConfigPath" -Verbose
                if (![System.IO.File]::Exists($agentConfigPath))
                {
                    Write-Error "File not found: $agentConfigPath" -Verbose
                    return
                }

                # Call the agent with the configure command and all the options (this creates the settings file) without prompting
                # the user or blocking the cmd execution
                Write-Verbose "Configuring agent '$($Agent)'" -Verbose

                $pat = $using:PersonalAccessToken
                #Write-Verbose "Configuring agent '$($pat)'" -Verbose
                .\config.cmd --unattended --url $serverUrl --auth PAT --token $pat --pool $using:PoolName --agent $Agent --runasservice
                
                Write-Verbose "Agent install output: $LASTEXITCODE" -Verbose
                
                Pop-Location
            }

            # Adding new Path to PSModulePath environment variable
            $CurrentValue = [Environment]::GetEnvironmentVariable("PSModulePath", "Machine")
            [Environment]::SetEnvironmentVariable("PSModulePath", $CurrentValue + ";C:\Modules", "Machine")
            $NewValue = [Environment]::GetEnvironmentVariable("PSModulePath", "Machine")
            Write-Verbose "new Path is: $($NewValue)" -verbose

            # Creating new Path
            if (!(Test-Path -Path C:\Modules -ErrorAction SilentlyContinue))
            { New-Item -ItemType Directory -Name Modules -Path C:\ -Verbose }

            # Installing New Modules and Removing Old
            #Foreach ($Module in $using:Modules)
            { Find-Module -Name $Module.Name -RequiredVersion $Module.Version -Repository PSGallery -Verbose | Save-Module -Path C:\Modules -Verbose }

            #$DefaultModules = "PowerShellGet", "PackageManagement","Pester"

            Foreach ($Module in $DefaultModules)
            {
                if ($tmp = Get-Module $Module -ErrorAction SilentlyContinue) {
                Remove-Module $Module -Force }
                Find-Module -Name $Module -Repository PSGallery -Verbose | Install-Module -Force -Confirm:$false -SkipPublisherCheck -Verbose
            }

            # Uninstalling old Azure PowerShell Modules
            #$programName = "Microsoft Azure PowerShell"
            #$app = Get-WmiObject -Class Win32_Product -Filter "Name Like '$($programName)%'" -Verbose
            #$app.Uninstall()

            Write-Verbose "Exiting DeployVSTSAgent.Config.ps1" -Verbose
        }
    }
  }
}