functions/private/Write-Log.ps1

function Write-Log {
    # write a message to the global log file
    [cmdletbinding()]
    param(
    [ValidateNotNullOrEmpty()]
    [string] $Message,
    [ValidateSet('Warning','Error','Verbose','Debug', 'Information')]
    [string] $Type = 'Information',
    [Parameter(Mandatory)]
    [ValidateNotNullOrEmpty()]
    [string] $Log
    )
    process {
        #Get the info about the calling script, function etc
        $callinginfo = (Get-PSCallStack)[1]
        #Set Source Information
        $Source = (Get-PSCallStack)[1].Location
        #Set Component Information
        $Component = (Get-Process -Id $PID).ProcessName
        #Set PID Information
        $ProcessID = $PID
        #Obtain UTC offset
        $DateTime = New-Object -ComObject WbemScripting.SWbemDateTime
        $DateTime.SetVarDate($(Get-Date))
        $UtcValue = $DateTime.Value
        $UtcOffset = $UtcValue.Substring(21, $UtcValue.Length - 21)
        #Set the order
        switch($Type){
            'Warning' {$Severity = 2}#Warning
            'Error' {$Severity = 3}#Error
            'Verbose' {$Severity = 4}#Verbose
            'Debug' {$Severity = 5}#Debug
            'Information' {$Severity = 6}#Information
        }#Switch
        $Line = "$Message"

        switch($Severity){
            2{
                Write-Warning $Line
            }
            3{
                
                <# if($Message.Exception.Message){
                    $Line += = @"
                    Command: $($Message.InvocationInfo.MyCommand)"
                                    ScriptName: $($Message.InvocationInfo.Scriptname)"
                    Line Number: $($Message.InvocationInfo.ScriptLineNumber)"`
                                    Column Number: $($Message.InvocationInfo.OffsetInLine)"
                    Line: $($Message.InvocationInfo.Line)
    "@
                } #>

                Write-Error $Line
            }
            4{
                Write-Verbose $Line
            }
            5{
                Write-Debug $Line
            }
            6{
                Write-Host $Line
            }
        }
        #$Message|out-file $script:Log -append -encoding default
        $LogEntry = `
        "<![LOG[$Line]LOG]!>" +`
        "<time=""$(Get-Date -Format HH:mm:ss.fff)$($UtcOffset)"" " +`
        "date=""$(Get-Date -Format M-d-yyy)"" "  +`
        "component=""$($CallingInfo.FunctionName)"" " + `
        "context=""$([System.Security.Principal.WindowsIdentity]::GetCurrent().Name)"" " +`
        "type=""$Severity"" " +`
        "thread=""$($ProcessID)"">"
        $Writer = new-object System.IO.StreamWriter $Log,$true
        $Writer.WriteLine($LogEntry.Replace("`r`n","`t"))
        $Writer.Close()
        $Writer.Dispose()
    }
}