Write-Log.ps1
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<#
.Synopsis Write-Log writes a message to a specified log file with the current time stamp. .DESCRIPTION The Write-Log function is designed to add logging capability to other scripts. In addition to writing output and/or verbose you can write to a log file for later debugging. .NOTES Created by: Jason Wasser @wasserja Modified: 11/24/2015 09:30:19 AM Changelog: * Code simplification and clarification - thanks to @juneb_get_help * Added documentation. * Renamed LogPath parameter to Path to keep it standard - thanks to @JeffHicks * Revised the Force switch to work as it should - thanks to @JeffHicks To Do: * Add error handling if trying to create a log file in a inaccessible location. * Add ability to write $Message to $Verbose or $Error pipelines to eliminate duplicates. .PARAMETER Message Message is the content that you wish to add to the log file. .PARAMETER Path The path to the log file to which you would like to write. By default the function will create the path and file if it does not exist. .PARAMETER Level Specify the criticality of the log information being written to the log (i.e. Error, Warning, Informational) .PARAMETER NoClobber Use NoClobber if you do not wish to overwrite an existing file. .EXAMPLE Write-Log -Message 'Log message' Writes the message to c:\Logs\PowerShellLog.log. .EXAMPLE Write-Log -Message 'Restarting Server.' -Path c:\Logs\Scriptoutput.log Writes the content to the specified log file and creates the path and file specified. .EXAMPLE Write-Log -Message 'Folder does not exist.' -Path c:\Logs\Script.log -Level Error Writes the message to the specified log file as an error message, and writes the message to the error pipeline. .LINK https://gallery.technet.microsoft.com/scriptcenter/Write-Log-PowerShell-999c32d0 #> function Write-Log { [CmdletBinding()] Param ( [Parameter(Mandatory=$true, ValueFromPipelineByPropertyName=$true)] [ValidateNotNullOrEmpty()] [Alias("LogContent")] [string]$Message, [Parameter(Mandatory=$false)] [Alias('LogPath')] [string]$Path='C:\Logs\PowerShellLog.log', [Parameter(Mandatory=$false)] [ValidateSet("Error","Warn","Info")] [string]$Level="Info", [Parameter(Mandatory=$false)] [switch]$NoClobber ) Begin { # Set VerbosePreference to Continue so that verbose messages are displayed. $VerbosePreference = 'Continue' } Process { # If the file already exists and NoClobber was specified, do not write to the log. if ((Test-Path $Path) -AND $NoClobber) { Write-Error "Log file $Path already exists, and you specified NoClobber. Either delete the file or specify a different name." Return } # If attempting to write to a log file in a folder/path that doesn't exist create the file including the path. elseif (!(Test-Path $Path)) { Write-Verbose "Creating $Path." $NewLogFile = New-Item $Path -Force -ItemType File } else { # Nothing to see here yet. } # Format Date for our Log File $FormattedDate = Get-Date -Format "yyyy-MM-dd HH:mm:ss" # Write message to error, warning, or verbose pipeline and specify $LevelText switch ($Level) { 'Error' { Write-Error $Message $LevelText = 'ERROR:' } 'Warn' { Write-Warning $Message $LevelText = 'WARNING:' } 'Info' { Write-Verbose $Message $LevelText = 'INFO:' } } # Write log entry to $Path "$FormattedDate $LevelText $Message" | Out-File -FilePath $Path -Append } End { } } |