Add logging to your powershell script

Function_Log-Message.ps1

<#
.SYNOPSIS
    This script initializes a global log file path and provides a function to log messages with different severity levels (Message, Warning, Error).
    
.DESCRIPTION
    The script defines a global variable for the log file path, which is created based on the script's root path or a custom path if provided. 
    It includes a Log-Message function to log messages to the file and display them in the console with appropriate colors.
    The script logs the start time and the end time along with the total execution time.
    
.PARAMETER LogFilePath
    A global variable defining the path of the log file. It can be set to a custom path if needed.
    
.PARAMETER Message
    The message to be logged.
    
.PARAMETER Warning
    A switch parameter to indicate if the message is a warning.
    
.PARAMETER Error
    A switch parameter to indicate if the message is an error.
    
.EXAMPLE
    .\YourScript.ps1
    This runs the script and logs the start time, sample messages, and the end time with the execution duration.
    Example included below.
    
.NOTES
    Author: Sebastian Rock
    Date: 31/05/2024
    Original author: https://www.sharepointdiary.com/2019/06/create-log-file-in-powershell-script.html
#>


# Define the global variable for the log file path, if executed in ISE with "Run selection" it uses the else part
if ($PSScriptRoot) {
    $Global:LogFilePath = Join-Path -Path $PSScriptRoot -ChildPath ("$(Get-Date -Format 'yyyy-MM-dd_HH-mm-ss').log")
} else {
    New-Item -Path "C:\Temp\Logs\" -ItemType Directory -Force
    $Global:LogFilePath = "C:\Temp\Logs\Log_$(Get-Date -Format 'yyyy-MM-dd_HH-mm-ss').log"
}

# If you want to set a custom log file path, uncomment the line below and set your path
# $Global:LogFilePath = "C:\Path\To\Your\CustomLogFile.log"

Function Log-Message {
    param (
        [Parameter(Mandatory=$true)] [string] $Message,
        [switch] $Warning,
        [switch] $Error
    )
 
    Try {
        # Add Content to the Log File
        $TimeStamp = (Get-Date).ToString("yyyy/MM/dd HH:mm:ss:fff")
        $Line = "$TimeStamp - $Message"
        
        Add-Content -Path $Global:LogFilePath -Value $Line

        # Set the default color and prefix
        $Color = "Green"
        $Prefix = "Message"

        # Change color and prefix based on the parameters
        if ($Warning.IsPresent) {
            $Color = "Yellow"
            $Prefix = "Warning"
        } elseif ($Error.IsPresent) {
            $Color = "Red"
            $Prefix = "Error  "
        }

        Write-Host "$Prefix : '$Line'" -ForegroundColor $Color
    } Catch {
        Write-Host "Error: $_.Exception.Message" -ForegroundColor Red
    }
}

#Log Start Time of the Script
$StartTime = (Get-Date)
Log-Message "Script Started at: $(Get-date -format 'yyyy/MM/dd HH:mm:ss')"

#### Your script starts here ####

Log-Message "Green message"
Log-Message "Yellow warning" -Warning
Log-Message "Red error" -Error


#### Your script ends here ####

#Log End Time
$EndTime = (Get-Date)
Log-Message "Script Ended at: $(Get-date -format 'yyyy/MM/dd HH:mm:ss')"

#Get Elapsed Time
$ElapsedTime = ($EndTime - $StartTime).Seconds
Log-Message "Script Execution Time: $ElapsedTime Seconds"