Added Promtail to Alloy migration scripts (#20)

Author: cortex-sr

Grafana/Alloy/Scripts/Migrate-Promtail-To-Alloy.ps1

@@ -0,0 +1,35 @@
+<#
+.DESCRIPTION
+    Migrates Promtail to Grafana Alloy.
+
+.EXAMPLE
+    .\Migrate-Promtail-To-Alloy.ps1 -PromtailConfig "C:\ProgramData\Cortex\Observability\Promtail\promtail-local-config.yaml"
+
+.NOTES
+    Version : 1.0.0.25410
+#>
+
+param(
+    [string]$PromtailConfig
+)
+
+Import-Module "$PSScriptRoot\Install-Alloy.psm1"
+Import-Module "$PSScriptRoot\Migrate-Promtail-To-Alloy.psm1"
+
+Install-RSAT
+
+Import-Module ActiveDirectory
+Set-Location $PSScriptRoot
+
+$ServiceUser = Get-ServiceUser
+
+Set-LocalSecurityPolicy -Username $($ServiceUser.UserName)
+Set-RegistryPermissions -Username $($ServiceUser.UserName)
+
+Install-Alloy -ServiceUser $ServiceUser
+Wait-ForAlloyReady -ServiceName "Alloy" -TimeoutSeconds 20
+Migrate-Promtail-To-Alloy -PromtailConfig $PromtailConfig
+
+Set-BearerToken-OnMigration -Username $($ServiceUser.UserName)
+
+Restart-Alloy

Grafana/Alloy/Scripts/Migrate-Promtail-To-Alloy.psm1

@@ -0,0 +1,178 @@
+<#
+.DESCRIPTION
+    Functions for migrating Promtail to Grafana Alloy.
+
+.NOTES
+    Version : 1.0.0.25410
+#>
+
+function Set-BearerTokenFilePath-OnMigration {
+    <#
+    .DESCRIPTION
+        Update config.alloy file to insert bearer_token_file after the LAST 'url =' line
+        in the loki.write endpoint block.
+    #>
+	
+    process {
+        Write-Output "Updating config.alloy file with bearer token file path"
+
+        $ConfigFile = Join-Path $PSScriptRoot "config.alloy"
+        $AuthFile   = Join-Path $PSScriptRoot "auth.secret"
+
+        if (-not (Test-Path -Path $ConfigFile -PathType Leaf)) {
+            throw "Config file not found: $ConfigFile"
+        }
+        if (-not (Test-Path -Path $AuthFile -PathType Leaf)) {
+            throw "Auth file not found: $AuthFile"
+        }
+
+        $lines = Get-Content -Path $ConfigFile
+
+        # Find the index of the last 'url =' line
+        $urlIndex = ($lines | ForEach-Object { $_ } | Select-String -Pattern '^\s*url\s*=' | Select-Object -Last 1).LineNumber
+        if (-not $urlIndex) {
+            throw "No 'url =' line found in $ConfigFile"
+        }
+
+        # Build the new file contents
+        $bearerPath = $AuthFile -replace '\\', '/'
+        $newLines   = @()
+        for ($i = 0; $i -lt $lines.Count; $i++) {
+            $newLines += $lines[$i]
+            if ($i -eq ($urlIndex - 1)) {
+                $newLines += "        bearer_token_file = `"$bearerPath`""
+            }
+        }
+
+        Set-Content -Path $ConfigFile -Value $newLines -Force
+
+        Write-Output "Updated config.alloy file"
+    }
+}
+
+function Set-BearerToken-OnMigration {
+	<#
+    .DESCRIPTION
+        Create Bearer Token file and restrict access.
+
+    .PARAMETER Username
+        The user name specified for the Grafana Alloy service to run as e.g. "Domain\Username"
+    #>
+
+    param
+    (
+        [Parameter(Mandatory = $true)]
+        [string]
+        $Username
+    )
+
+    process {
+		Write-Output "Creating bearer token file"
+		
+		$AuthFile = (Join-Path $PSScriptRoot "auth.secret")
+		
+		$BearerToken = Read-Host -Prompt "Enter bearer token used by Loki for authentication" -AsSecureString
+		
+		New-Item $AuthFile -ItemType File -Value ([pscredential]::new('BearerToken',$BearerToken).GetNetworkCredential().Password) -Force | Out-Null
+		
+		Write-Output "Created bearer token file"
+
+		Set-BearerTokenFilePermissions -AuthFile $AuthFile -Username $Username
+	
+		Set-BearerTokenFilePath-OnMigration
+	}
+}
+
+function Migrate-Promtail-To-Alloy {
+    [CmdletBinding()]
+    param(
+        [Parameter(Mandatory = $true)]
+        [string]$PromtailConfig
+    )
+
+    begin {
+        $exePath      = Join-Path $env:ProgramFiles 'GrafanaLabs\Alloy\alloy-windows-amd64.exe'
+        $outputPath   = Join-Path $env:ProgramData 'Cortex\Observability\Grafana Alloy\config.alloy'
+        $outputDir    = Split-Path -Path $outputPath -Parent
+		$sourceConfig = (Resolve-Path -Path $PromtailConfig -ErrorAction Stop).Path
+    }
+
+    process {
+        Write-Output "Starting Promtail to Grafana Alloy config migration"
+
+        if (-not (Test-Path -Path $exePath -PathType Leaf)) {
+            throw "Alloy executable not found at '$exePath'. Ensure Alloy is installed before migrating."
+        }
+        if (-not (Test-Path -Path $sourceConfig -PathType Leaf)) {
+            throw "Promtail config not found at '$sourceConfig'."
+        }
+        if (-not (Test-Path -Path $outputDir -PathType Container)) {
+            Write-Output "Creating output directory: $outputDir"
+            New-Item -ItemType Directory -Path $outputDir -Force | Out-Null
+        }
+
+        try {
+            & $exePath convert --source-format=promtail --output=$outputPath $sourceConfig
+            if ($LASTEXITCODE -ne 0) {
+                throw "Conversion failed with exit code $LASTEXITCODE."
+            }
+        }
+        catch {
+            throw "Grafana Alloy convert invocation failed: $($_.Exception.Message)"
+        }
+
+        if (-not (Test-Path -Path $outputPath -PathType Leaf)) {
+            throw "Conversion completed but '$outputPath' was not created."
+        }
+
+        Write-Output "Migrated Promtail to Grafana Alloy config"
+    }
+}
+
+
+function Restart-Alloy {
+    [CmdletBinding()]
+    param(
+        [string]$ServiceName = 'alloy'
+    )
+    process {
+        Write-Output "Restarting service '$ServiceName'..."
+        try {
+            Restart-Service -Name $ServiceName -Force -ErrorAction Stop
+            Write-Output "Service '$ServiceName' restarted successfully"
+        }
+        catch {
+            throw "Failed to restart service '$ServiceName': $($_.Exception.Message)"
+        }
+    }
+}
+
+function Wait-ForAlloyReady {
+    <#
+    .SYNOPSIS
+        Waits until the Alloy service is running.
+    .PARAMETER ServiceName
+        Name of the Alloy Windows service. Defaults to 'alloy'.
+    .PARAMETER TimeoutSeconds
+        Maximum number of seconds to wait. Defaults to 60.
+    #>
+    [CmdletBinding()]
+    param(
+        [string]$ServiceName = 'alloy',
+        [int]$TimeoutSeconds = 60
+    )
+
+    $stopwatch = [System.Diagnostics.Stopwatch]::StartNew()
+    while ($stopwatch.Elapsed.TotalSeconds -lt $TimeoutSeconds) {
+        $service = Get-Service -Name $ServiceName -ErrorAction SilentlyContinue
+
+        if ($service -and $service.Status -eq 'Running') {
+            Write-Output "Alloy service is running."
+            return
+        }
+
+        Start-Sleep -Seconds 1
+    }
+
+    throw "Timeout: Alloy service '$ServiceName' not running after $TimeoutSeconds seconds."
+}