A Powershell Script for Installing Promtail on Windows

install_promtail.ps1

param (
    [string]$hostUrl = $(if ($env:PROMTAIL_HOST_URL) { $env:PROMTAIL_HOST_URL } else { "http://localhost:3100/loki/api/v1/push" }),
    [string]$eventTypesStr = $(if ($env:PROMTAIL_EVENT_TYPES) { $env:PROMTAIL_EVENT_TYPES } else { "Application,Security,System" })
)

# Variables
$latestReleaseUrl = "https://github.com/grafana/loki/releases/latest"
$repoUrl = "https://github.com/grafana/loki"
$winswUrl = "https://github.com/winsw/winsw/releases/download/v2.12.0/WinSW-x64.exe"
$outputDir = "C:\"
$promtailDir = "C:\Program Files\Promtail"

# Parse event types and validate
$eventTypes = $eventTypesInput -split ","
$validEventTypes = @("Application", "Security", "System")

foreach ($event in $eventTypes) {
    if ($event -notin $validEventTypes) {
        throw "Invalid event type specified: $event. Valid event types are 'Application', 'Security', and 'System'."
    }
}

# Check and recreate directory if it exists
if (Test-Path $promtailDir) {
    Remove-Item $promtailDir -Recurse -Force
}
New-Item -ItemType Directory -Path $promtailDir

# Get the latest release version number from the redirect URL
$redirectedUrl = (Invoke-WebRequest -Uri $latestReleaseUrl -UseBasicParsing).BaseResponse.ResponseUri.AbsoluteUri
$latestVersion = ($redirectedUrl -split '/tag/')[-1].Trim('/')

# Construct the download URL
$installerName = "promtail-windows-amd64.exe.zip"
$downloadUrl = "$repoUrl/releases/download/$latestVersion/$installerName"
$outputFile = Join-Path -Path $outputDir -ChildPath $installerName

# Download the installer
Write-Host "Now downloading: $downloadUrl"
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12 
Invoke-WebRequest -Uri $downloadUrl -OutFile $outputFile

# Remove the previous extracted file if it exists
$extractedFileDestination = Join-Path -Path $outputDir -ChildPath "promtail-windows-amd64.exe"
if (Test-Path $extractedFileDestination) {
    Remove-Item $extractedFileDestination -Force
}

# Extract the downloaded zip file
Expand-Archive -Path $outputFile -DestinationPath $outputDir

# Rename and move the extracted file
Rename-Item -Path $extractedFileDestination -NewName "promtail.exe"
Move-Item -Path "$outputDir\promtail.exe" -Destination $promtailDir

# Download WinSW
$winswPath = Join-Path -Path $promtailDir -ChildPath "WinSW.exe"
Invoke-WebRequest -Uri $winswUrl -OutFile $winswPath

# Rename WinSW.exe to match service name
Rename-Item -Path $winswPath -NewName "PromtailService.exe"
$winswPath = Join-Path -Path $promtailDir -ChildPath "PromtailService.exe"

# Create the scrape_configs dynamically based on the event types provided
$scrapeConfigs = @()
foreach ($event in $eventTypes) {
    $lowercaseEvent = $event.ToLower()
    $scrapeConfig = @"
- job_name: windows_$lowercaseEvent
  windows_events:
    use_incoming_timestamp: false
    bookmark_path: "./bookmark_${lowercaseEvent}_logs.xml"
    eventlog_name: "$event"
    xpath_query: '*'
    labels:
      job: windows_$lowercaseEvent
"@
    $scrapeConfigs += $scrapeConfig
}

# Create the Promtail configuration file
$configFileContent = @"
server:
  http_listen_port: 9080
  grpc_listen_port: 0

clients:
  - url: $hostUrl

positions:
  filename: $promtailDir\positions.yaml

scrape_configs:
$($scrapeConfigs -join "`n")
"@
$configFilePath = Join-Path -Path $promtailDir -ChildPath "promtail-windows.yaml"
$configFileContent > $configFilePath

# Create WinSW configuration
$winswConfigContent = @"
<service>
    <id>Promtail</id>
    <name>Promtail</name>
    <description>Promtail is an agent which ships the contents of local logs to a private Loki instance or Grafana Cloud.</description>
    <executable>$promtailDir\promtail.exe</executable>
    <arguments>--config.file=`"$configFilePath`"</arguments>
    <startmode>Automatic</startmode>
</service>
"@
$winswConfigPath = Join-Path -Path $promtailDir -ChildPath "PromtailService.xml"
$winswConfigContent > $winswConfigPath

# Install and start the service using WinSW
& $winswPath install
& $winswPath start

# Validate the service status
Start-Sleep -Seconds 5 # Giving some time for the service to start
$serviceStatus = (Get-Service "Promtail").Status
if ($serviceStatus -ne 'Running') {
    throw "Error: The Promtail service could not be started correctly."
}

# Cleanup: remove downloaded zip file
if (Test-Path $outputFile) {
    Remove-Item -Path $outputFile -Force
}

Write-Host "Installation, configuration, and service creation completed!"