Logging Script

<#
.SYNOPSIS
    Module for logging.
.DESCRIPTION
    Developer:  Mike Polselli
    PSVersion:  5.0
    Date:       9/14/2018
    Language:   PowerShell
    Purpose:    This module is used to store the logging functions used in all scripts.
    .EXAMPLE
    Start-Log -ScriptName MyScript
    try {
        Disable-ADUser $User -ErrorAction Stop
        Write-Log -LogMessage "Disabled $($User.Name) and moved them to the $($DestinationOU.DistinguishedName) OU."
    } 
    catch {
        Write-LogError -ErrorMessage "Error disabling $($User.Name) and moving them to the $($DestinationOU.DistinguishedName) OU."
    }
    Stop-Log
#>

### Functions ###
function Get-LogTime {
    # Is used to pass a current time stamp whenever output is generated.
    (Get-Date).ToString('yyyy-MM-dd hh:mm:ss tt')
}
function Start-Log {
    <#
    .SYNOPSIS
        Starts the log file for the script it is run in.
    .PARAMETER ScriptName
    Provides a name to the log file.
    .EXAMPLE
    Start-Log -ScriptName MyScript
    #>
    [cmdletbinding(DefaultParameterSetName = "Primary")]
    param (
        [Parameter(ParameterSetName, Position = 0, Mandatory = $true)][string]$Global:ScriptName,
        [Parameter(ParameterSetName)][switch]$LocalLog
    )
    $Date = (Get-Date).ToString('yyyy-MM-dd')
    $Script:Log = "\\$env:USERDOMAIN\IT\Scripts\Logs\$ScriptName`_$env:COMPUTERNAME`_$Date.txt"
    if ($LocalLog) {
        $Script:Log = "C:\IT\Logs\$ScriptName`_$Date.txt"
    }
    $TestPath = Test-Path $Log
    if ($TestPath -eq $false) {
        New-Item -Path $Log -Type File -Force | Out-Null
        Write-Output "$(Get-LogTime) ========== $Log did not exist. Creating. ==========" >> $Log
        Write-Output "$(Get-LogTime) ========== $Log created, continuing script. ==========" >> $Log
        Write-Output "$(Get-LogTime) ========== $ScriptName started. ==========" >> $Log
    }
    else {
        Write-Output "$(Get-LogTime) ========== $ScriptName started. ==========" >> $Log
    }
}

function Write-Log {
    <#
    .SYNOPSIS
    Used to store the information that will be passed to the log file.
    .PARAMETER LogMessage
    Information you wish to pass to the log file goes here.
    .PARAMETER ShowOutput
    If this switch is used the LogMessage information will also be printed to the console.
    .EXAMPLE
    Write-Log -LogMessage 'Disabled some users and moved them to a different OU'
    .EXAMPLE
    Write-Log -LogMessage "Disabled $($User.Name) and moved them to the $($DestinationOU.DistinguishedName) OU."
    .EXAMPLE
    Write-Log -LogMessage "Disabled $($User.Name) and moved them to the $($DestinationOU.DistinguishedName) OU." -ShowOutput
    
    2018-12-12 04:45:59 PM - Disabled John Doe and moved them to the Disabled OU.
    #>
    [cmdletbinding(DefaultParameterSetName = "Primary")]
    param (
        [Parameter(ParameterSetName, Position = 0, Mandatory = $true)]$LogMessage,
        [Parameter(ParameterSetName)][switch]$ShowOutput
    )
    if ($ShowOutput) {
        "$(Get-LogTime) - $LogMessage" >> $Log
        Write-Output "$(Get-LogTime) - $LogMessage"
    }
    else {
        "$(Get-LogTime) - $LogMessage" >> $Log
    }

}

function Write-LogError {
    <#
    .SYNOPSIS
    Used to store the error messages that will be passed to the log file.
    .PARAMETER ErrorMessage
    Error messages that you wish to pass to the log file goes here.
    .PARAMETER ShowOutput
    If this switch is used the ErrorMessage information will also be printed to the console.
    .EXAMPLE
    Write-LogError -ErrorMessage 'Failed to disable some users and move them to a different OU'
    .EXAMPLE
    Write-LogError -ErrorMessage "Error disabling $($User.Name) and moving them to the $($DestinationOU.DistinguishedName) OU."
    .EXAMPLE
    Write-LogError -ErrorMessage "Error Disabling $($User.Name) and moving them to the $($DestinationOU.DistinguishedName) OU." -ShowOutput

    /-------------------------------------------------------------------------------------------\
    |2018-12-12 04:48:45 PM ERROR - Error Disabling John Doe and moving them to the Disabled OU.|
    \-------------------------------------------------------------------------------------------/
    .EXAMPLE
    try {Get-ChildItem C:\NotARealPath -ErrorAction Stop} catch {Write-LogError $PSItem.Exception.Message -ShowOutput}
    
    /--------------------------------------------------------------------------------------------\
    |2018-12-12 04:48:45 PM ERROR - Cannot find path 'C:\NotARealPath' because it does not exist.|
    \--------------------------------------------------------------------------------------------/
    #>
    [cmdletbinding(DefaultParameterSetName = "Primary")]
    param (
        [Parameter(ParameterSetName, Position = 0, Mandatory = $true)]$ErrorMessage,
        [Parameter(ParameterSetName)][switch]$ShowOutput
    )
    $Length = $ErrorMessage.Length + 31
    $Dashes = ('-' * $Length)
    if ($ShowOutput) {
        Write-Output "/$Dashes\"
        Write-Output "|$(Get-LogTime) ERROR - $ErrorMessage|"
        Write-Output "\$Dashes/"
        "/$Dashes\" >> $Log
        "|$(Get-LogTime) ERROR - $ErrorMessage|" >> $Log
        "\$Dashes/" >> $Log
    }
    else {
        "/$Dashes\" >> $Log
        "|$(Get-LogTime) ERROR - $ErrorMessage|" >> $Log
        "\$Dashes/" >> $Log    
    }
}

function Stop-Log {
    <#
    .SYNOPSIS
        Stops the log file for the script it is run in.
    #>
    Write-Output "$(Get-LogTime) ========== $ScriptName finished. ==========" >> $Log
}
### Functions ###