Powershell logging setup that supports files, console output and event logs - powershell

Question

Is there a way to do logging in a Powershell script so that
a single call can be made to log a message
this message is then routed to none/any/multiple (depending on config) of the following
standard console output
a log file
windows event logs
Sort of like python's logging framework or log4j in Java, where the logging targets are configured separately from actual the logging of messages.

Answer 1

You can use logger module or script.
<#
.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.
Changelog:
* Code simplification and clarification
* Added documentation.
* Renamed LogPath parameter to Path to keep it standard.
* Revised the Force switch to work as it should.
To Do:
* Add error handling if trying to create a log file in a inaccessible location.
* Add ability to write $Message to $Verbose or $Error pipelines to eliminate
duplicates.
.PARAMETER Message
Message is the content that you wish to add to the log file.
.PARAMETER Path
The path to the log file to which you would like to write. By default the function will
create the path and file if it does not exist.
.PARAMETER Level
Specify the criticality of the log information being written to the log (i.e. Error, Warning, Informational)
.PARAMETER NoClobber
Use NoClobber if you do not wish to overwrite an existing file.
.EXAMPLE
Write-Log -Message 'Log message'
Writes the message to c:\Logs\PowerShellLog.log.
.EXAMPLE
Write-Log -Message 'Restarting Server.' -Path c:\Logs\Scriptoutput.log
Writes the content to the specified log file and creates the path and file specified.
.EXAMPLE
Write-Log -Message 'Folder does not exist.' -Path c:\Logs\Script.log -Level Error
Writes the message to the specified log file as an error message, and writes the message to the error pipeline.
#>
function Write-Log
{
[CmdletBinding()]
Param
(
[Parameter(Mandatory=$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
{
}
}
Then just call it out wherever you want in script :
Write-Log -Message "################ Script Started #############################" -Level Info
and if you want to redirect the error then call it in catch block:
try{ }
catch
{
{Write-Log -Message $_.Exception.Message -Level Error}
}
Note: Make sure in that case you compile the function in the beginning, else PS will not be able to use it inside the blocks because the scope will vary.
This will give you console and file output and you can script to direct to eventlog even. Hope it helps.