omsAgent

1.0

publicFunctions/Uninstall-omsAgent.ps1

<#
    .Synopsis
       Un-installs the OMS agent on remote computers.
    .DESCRIPTION
       Un-installs the OMS agent on remote computers.
    .EXAMPLE
        Uninstall-OmsAgent -computerName 'computer1', 'computer2' -Verbose
    .NOTES
        Written by Ben Taylor
        Version 1.0, 31.07.2016
#>
function Uninstall-OmsAgent {
    [CmdletBinding(SupportsShouldProcess = $True, ConfirmImpact = 'High')]
    [OutputType()]
    Param (
        [Parameter(Mandatory = $false, ValueFromPipeline=$True, valuefrompipelinebypropertyname=$true,  Position=0)]
        [ValidateNotNullOrEmpty()]
        [Alias('IPAddress', 'Name')]
        [string[]]
        $computerName = $env:COMPUTERNAME,
        [Parameter()]
        [System.Management.Automation.PSCredential]
        [System.Management.Automation.Credential()]
        $Credential
    )

    Begin {
        $commonSessionParams = @{
            ErrorAction = 'Stop'
        }

        If ($PSBoundParameters['Credential']) {
            $commonSessionParams.Credential = $Credential
        }
    } Process {
        forEach ($computer in $computerName) {
            try {
                Write-Verbose "[$(Get-Date -Format G)] - $computer - Creating Remote PS Session"
                $psSession = New-PSSession -ComputerName $computer @commonSessionParams

                Write-Verbose "[$(Get-Date -Format G)] - $computer - Checking if OMS is Installed"
                $omsInstall = Get-omsAgentInternal -computerName $computer -session $psSession

                if($omsInstall) {
                    If ($Pscmdlet.ShouldProcess($computer, 'Uninstall OMS Agent')) {
                        Write-Verbose "[$(Get-Date -Format G)] - $computer - OMS is installed so will try to uninstall"

                        Invoke-Command -Session $psSession -ScriptBlock {
                            $uninstallString = ($USING:omsInstall.UninstallString).ToLower().Replace("/i", "").Replace("msiexec.exe", "")
                            Start-Process "msiexec.exe" -arg "/X $uninstallString /qn" -Wait
                        } -ErrorAction Stop

                        $omsInstallStatus = Get-omsAgentInternal -computerName $computer -session $psSession -ErrorAction SilentlyContinue

                        if(-not($omsInstallStatus)) {
                            Write-Verbose "[$(Get-Date -Format G)] - $computer - OMS uninstalled correctly"
                        } else {
                            Write-Error "[$(Get-Date -Format G)] - $computer - OMS didn't uninstall correctly based registry check"
                        }
                    }
                } else {
                    Write-Verbose "[$(Get-Date -Format G)] - $computer - OMS not installed so skipping uninstall process"
                }
            } catch {
                Write-Error $_
            } Finally {
                if($null -ne $psSession) {
                    Write-Verbose "[$(Get-Date -Format G)] - $computer - Closing Remote PS Session"
                    Remove-PSSession $psSession -WhatIf:$false -Confirm:$false
                }
            }
        }
    }
}