installvstsagent.ps1

# Downloads the Visual Studio Team Services Build Agent and installs on the new machine
# and registers with the Visual Studio Team Services account and build agent pool

# Enable -Verbose option
[CmdletBinding()]
Param(
[Parameter(Mandatory=$true)]$VSTSAccount,
[Parameter(Mandatory=$true)]$PersonalAccessToken,
[Parameter(Mandatory=$true)]$AgentName,
[Parameter(Mandatory=$true)]$PoolName
)

Write-Verbose "Entering InstallVSOAgent.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())
New-Item -ItemType Directory -Force -Path $agentTempFolderName
Write-Verbose "Temporary Agent download folder: $agentTempFolderName" -verbose

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

$retryCount = 3
$retries = 1
Write-Verbose "Downloading Agent install files" -verbose
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/latest"
    $latestReleaseDownloadUrl = ($latestRelease.assets | ? { $_.name -like "*win7-x64*" }).browser_download_url
    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 occured downloading agent: $exceptionText in try number $retries" -verbose
    $retries++
    Start-Sleep -Seconds 30 
  }
} 
while ($retries -le $retryCount)

# Construct the agent folder under the main (hardcoded) C: drive.
$agentInstallationPath = Join-Path "C:" $AgentName 
# Create the directory for this agent.
New-Item -ItemType Directory -Force -Path $agentInstallationPath 

# Create a folder for the build work
New-Item -ItemType Directory -Force -Path (Join-Path $agentInstallationPath $WorkFolder)


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" -Verbose

# Set the current directory to the agent dedicated one previously created.
Push-Location -Path $agentInstallationPath

.\config.cmd --unattended --url $serverUrl --auth PAT --token $PersonalAccessToken --pool $PoolName --agent $AgentName --runasservice

Pop-Location

Write-Verbose "Agent install output: $LASTEXITCODE" -Verbose

Write-Verbose "Exiting InstallVSTSAgent.ps1" -Verbose