Advanced Windows PowerShell Scripting Video Training

Advanced Windows PowerShell Scripting Video Training
Advanced Windows PowerShell Scripting Video Training

Thursday, October 6, 2016

Creating an Error Log: Option 1 - Use a Custom Object with a CSV file

This is day 4 of how to create an error log.

Today we will be using a custom object for our error log.  We can actually do this in two different ways.  We could create a custom object with specific information from the error object produced by PowerShell or create a custom log ourselves.

If we utilize the object created by PowerShell with a CSV error log, then we need to make sure that we only utilized 2D data.  That is information that is not a complex object itself.

Function Test-ADUsers
{
    [CmdletBinding()]
    Param (
        [parameter(Mandatory=$true)]
        [String[]]
        $Names,

        [Switch]
        $NoAppend

# Begin Support Functions
    )
    Function Test-ErrorLog
    {
    [CmdletBinding()]
    Param (
        [parameter(Mandatory=$true)]
        [String]
        $Path,

        [parameter(Mandatory=$true)]
        [String]
        $Name
        )

        # Test the path.
        If (!(Test-Path -Path $Path))
        {
            Write-Verbose "Creating the directory $Path"
            New-Item -Path $Path -ItemType Directory
        }

        # Test the file
        If (!(Test-Path -Path "$Path\$Name"))
        {
            Write-Verbose "Creating the file $Name"
            New-Item -Path "$Path\$Name" -ItemType File
        }

    } # END: Function Test-ErrorLog

# End Support Functions

    # Verify that the error log is present.
    Test-ErrorLog -Path c:\ps\error -Name Errorlog.csv

    # If -NoAppend is TRUE, then clear the error log.
    If(($NoAppend))
    {
        Write-Verbose "Clearing the error log"
        Remove-Item -Path C:\PS\error\ErrorLog.csv -Force
        New-Item -Path C:\PS\error -Name ErrorLog.csv -ItemType File     
    }

    ForEach ($Name in $Names)
    {
        Try {Get-ADUser -Identity $Name -ErrorAction Stop -ErrorVariable MyError}
        Catch
        {
            $Obj = New-Object -TypeName PSObject -Property @{
                TimeGenerated = (Get-Date).ToString()
                UserName = $Name
                Message = $MyError.Message
                }
            $Obj | Export-csv -Path C:\PS\Error\ErrorLog.csv -Append

            $MyError | Select *
        }
    }

} # END: Function Test-ADUsers

Test-ADUsers -Names "Administrator", "Bad", "Administrator"  -Verbose

Take a look at the Get-ADUser cmdlet.  We added the –ErrorVariable parameter to store our error object. Next, look at the Catch block. You can see the creation of the object to be sent to our error log.

TimeGenerated will be the time the error is recorded.  Notice, I’m only sending a string, not a SYSTEM.DATTIME object that is normally produce by Get-Date
UserName is the name of the user that we are currently testing.
Message contains the message property of the error object.


The Export-CSV cmdlet also has a huge advantage.  We are using the –Append parameter.  This means that we will add new records as needed.  The –NoAppend parameter that we created earlier prevents us from appending to a file that already exists.  The –Append parameter of Export-CSV is needed to ensure that we record all error instances when the code is ran.  Otherwise we will only have a record of the last error recorded.

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