Create VM Snapshot

$ErrorActionPreference = 'Stop'
<# Creates a snapshot of the selected VMware virtual machine(s).
   Datetime will be added to the default snapshot name 'ControlUpSnapshot' if this is used.  
    Steps:
    1. Check hypervisor type, only VMware is supported
    2. Connect to VCenter server
    3. Create snapshot
    - If the default snapshot name ControlUpSnapshot is used or the name field is left empty, a datetime (European format) stamp is appended to the field, eg. (ControlUpSnapshot)1204161341
    - If the description field is left empty, default text 'Snapshot created in ControlUp Console' will be used.
    4. Disconnect from the VCenter server

    Script requires VMWare PowerCLI to be installed on the machine it runs on.

    Author: Ton de Vreede, 5/12/2016
#>

$strHypervisorPlatform = $args[0]
$strVCenter = $args[1]
$strVMName = $args[2]
$strSnapshotName = $args[3]
$strSnapshotDescription = $args[4]

Function Feedback {
    Param (
        [Parameter(Mandatory = $true,
        Position = 0)]
        [string]$Message,
        [Parameter(Mandatory = $false,
        Position = 1)]
        $Exception,
        [switch]$Oops
    )

    # This function provides feedback in the console on errors or progress, and aborts if error has occured.
    If (!$Exception -and !$Oops) {
        # Write content of feedback string
        Write-Host $Message -ForegroundColor 'Green'
    }

    # If an error occured report it, and exit the script with ErrorLevel 1
    Else {
        # Write content of feedback string but to the error stream
        $Host.UI.WriteErrorLine($Message) 
        
        # Display error details
        If ($Exception) {
            $Host.UI.WriteErrorLine("Exception detail:`n$Exception")
        }

        # Exit errorlevel 1
        Exit 1
    }
}

Function Test-HypervisorPlatform {
    Param (
        [Parameter(Mandatory = $true,
            Position = 0)]
        [string]$strHypervisorPlatform
    )
    # This function checks if the hypervisor is supported by this script.
    If ($strHypervisorPlatform -ne 'VMWare') {
        Feedback -Message "Currently this script based action only supports VMWare, selected guest $strVMName is not running on VMWare" -Oops
    }
}

function Load-VMWareModules {
    <# Imports VMware PowerCLI modules, with a -Prefix $Prefix is supplied (desirable to avoid conflict with Hyper-V cmdlets)
      NOTES:
      - The required modules to be loaded are passed as an array.
      - If the PowerCLI versions is below 6.5 some of the modules can't be imported (below version 6 it is Snapins only) using so Add-PSSnapin is used (which automatically loads all VMWare modules) BUT 
            If a -Prefix has been specified AND Add-PSSnapin has to be used because the PowerCLI version is too low loading the module will fail because the -Prefix option can't be used with Add-PSSnapin
    #>
    param (    
        [parameter(Mandatory = $true,
            ValueFromPipeline = $false)]
        [array]$Components,
        [parameter(Mandatory = $false,
            ValueFromPipeline = $false)]
        [string]$Prefix
    )
    # Try Import-Module for each passed component, try Add-PSSnapin if this fails (only if -Prefix was not specified)
    if ($Prefix) {
        try {
            # Import each specified module
            foreach ($component in $Components) {
                $null = Import-Module -Name VMware.$component -Prefix $Prefix
            }
        }
        catch {
            Write-Host "The required VMWare PowerCLI components were not found as PowerShell modules. Because a -Prefix is used in loading the components Add-PSSnapin can not be used. Please make sure VMWare PowerCLI version 6.5 or higher is installed and available for the user running the script."
            Exit 1
        }
    }
    else {
        # Import each module, if Import-Module fails try Add-PSSnapin
        foreach ($component in $Components) {
            try {
                $null = Import-Module -Name VMware.$component
            }
            catch {
                try {
                    $null = Add-PSSnapin -Name VMware.$component
                }
                catch {
                    Write-Host "The required VMWare PowerCLI components were not found as modules or snapins. Please make sure VMWare PowerCLI (version 6.5 or higher preferred) is installed and available for the user running the script."
                    Exit 1
                }
            }
        }
    }
}

Function Connect-VCenterServer {
    Param (
        [Parameter(Mandatory = $true,
            Position = 0)]
        [string]$VCenterName
    )
    Try {
        # Connect to VCenter server
        Connect-VMWareVIServer $VCenterName -WarningAction SilentlyContinue -Force
    }
    Catch {
        Feedback "There was a problem connecting to VCenter server $VCenterName. Please correct the error and try again." -Exception $_
    }
}

Function Disconnect-VCenterServer  {
    Param (
        [Parameter(Mandatory = $true,
            Position = 0)]
        [string]$VCenter
    )
    # This function closes the connection with the VCenter server 'VCenter'
    try {
        # Disconnect from the VCenter server
        Disconnect-VMWareVIServer -Server $VCenter -Confirm:$false
    }
    catch {
        Feedback "There was a problem disconnecting from VCenter server $VCenter." -Exception $_
    }
}

Function Create-VMSnapshot {
    Param
    (
        [parameter(mandatory = $true, Position = 0)]
        [string]$strVMName,
        [parameter(mandatory = $true, Position = 1)]
        [string]$strSnapshotName,
        [parameter(mandatory = $true, Position = 2)]
        [string]$strSnapshotDescription
    )

    Function CreateTheSnapshot {
        Try {
            # Create the snapshot
            $objNewSnapshot = New-VMWareSnapshot -VM $strVMName -Server $VCenter -Name $strSnapshotName -Description $strSnapshotDescription

            # Display snapshot info
            $objNewSnapshot | Select-Object -Property Name, Description, Created, @{
                Name       = 'SizeMB'
                Expression = {
                    [math]::round($_.SizeMB, 2)
                }
            }, ParentSnapshot |
                Format-Table -AutoSize
        }
        catch {
            Feedback -Message "There was a problem creating snapshot $strSnapshotName of virtual machine $strVMName" -Exception $_
        }
    }


    # This function creates a new snapshot of machine '$strVMName' called '$strSnapshotName'
    Try {
        Get-Snapshot -VM $strVMName -Server VCenter -Name $strSnapshotName > $null
        # Method succeeded so snapshot $strSnapshotname already exists
        Feedback -Message "Snapshot $strSnapshotName of virtual machine $strVMName already exists!" -Oops
    }
    Catch {
        # Get-Snapshot failed to retrieve snapshot so it does not exist
        # Call Snapshot creation function
        CreateTheSnapshot
    }
}

# Check all the arguments have been passsed
If ($args.count -lt 5) {
    Feedback  -Message "The script did not get enough arguments from the Console. This can occur if you are not connected to the VM's hypervisor.`nPlease connect to the hypervisor in the ControlUp Console and try again." -Oops
}

# Check name and description for the snapshot
If (($strSnapshotName -eq 'ControlUpSnapshot') -or (!$strSnapshotName)) {
    $strSnapshotName = 'ControlUpSnapshot-' + (Get-Date -Format yyyyMMddHHmm)
}
If (!$strSnapshotDescription) {
    $strSnapshotDescription = 'Created in ControlUp console'
}

# Check the Hypervisor is supported
Test-HypervisorPlatform -strHypervisorPlatform $strHypervisorPlatform

# Import the VMWare PowerCLI modules
Load-VMWareModules -Components @('VimAutomation.Core') -Prefix 'VMWare'

# Connect to VCenter server for VMWare
$VCenter = Connect-VCenterServer $strVCenter

# Create the snapshot
Create-VMSnapshot -strVMName $strVMName -strSnapshotName $strSnapshotName -strSnapshotDescription $strSnapshotDescription

# Disconnect from the VCenter server
Disconnect-VCenterServer -VCenter $VCenter