functions/Remove-DbaDatabaseSnapshot.ps1

#ValidationTags#FlowControl#
function Remove-DbaDatabaseSnapshot {
    <#
.SYNOPSIS
Removes database snapshots
 
.DESCRIPTION
Removes (drops) database snapshots from the server
 
.PARAMETER SqlInstance
The SQL Server that you're connecting to
 
.PARAMETER SqlCredential
Credential object used to connect to the SQL Server as a different user
 
.PARAMETER Database
Removes snapshots for only this specific base db
 
.PARAMETER ExcludeDatabase
Removes snapshots excluding this specific base dbs
 
.PARAMETER Snapshot
Restores databases from snapshot with this name only
 
.PARAMETER AllSnapshots
Specifies that you want to remove all snapshots from the server
 
.PARAMETER Force
Will forcibly kill all running queries that prevent the drop process.
 
.PARAMETER WhatIf
Shows what would happen if the command were to run
 
.PARAMETER Confirm
Prompts for confirmation of every step.
 
.PARAMETER PipelineSnapshot
Internal parameter
 
.PARAMETER EnableException
        By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
        This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
        Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
         
.NOTES
Tags: Snapshot, Database
Author: niphlod
 
Website: https://dbatools.io
Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
.LINK
 https://dbatools.io/Remove-DbaDatabaseSnapshot
 
.EXAMPLE
Remove-DbaDatabaseSnapshot -SqlInstance sqlserver2014a
 
Removes all database snapshots from sqlserver2014a
 
.EXAMPLE
Remove-DbaDatabaseSnapshot -SqlInstance sqlserver2014a -Snapshot HR_snap_20161201, HR_snap_20161101
 
Removes database snapshots named HR_snap_20161201 and HR_snap_20161101
 
.EXAMPLE
Remove-DbaDatabaseSnapshot -SqlInstance sqlserver2014a -Database HR, Accounting
 
Removes all database snapshots having HR and Accounting as base dbs
 
.EXAMPLE
Remove-DbaDatabaseSnapshot -SqlInstance sqlserver2014a -Snapshot HR_snapshot, Accounting_snapshot
 
Removes HR_snapshot and Accounting_snapshot
 
.EXAMPLE
Get-DbaDatabaseSnapshot -SqlInstance sql2016 | Where SnapshotOf -like '*dumpsterfire*' | Remove-DbaDatabaseSnapshot
 
Removes all snapshots associated with databases that have dumpsterfire in the name
 
#>

    [CmdletBinding(SupportsShouldProcess = $true)]
    Param (
        [parameter(Mandatory = $false, ValueFromPipeline = $true)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [Alias("Credential")]
        [PSCredential]
        $SqlCredential,
        [Alias("Databases")]
        [object[]]$Database,
        [object[]]$ExcludeDatabase,
        [object[]]$Snapshot,
        [parameter(ValueFromPipeline = $true)]
        [object]$PipelineSnapshot,
        [switch]$AllSnapshots,
        [switch]$Force,
        [switch][Alias('Silent')]$EnableException
    )

    process {
        if (!$Snapshot -and !$Database -and !$AllSnapshots -and $null -eq $PipelineSnapshot -and !$ExcludeDatabase) {
            Stop-Function -Message "You must specify -Snapshot, -Database, -Exclude or -AllSnapshots"
            return
        }
        # handle the database object passed by the pipeline
        # do we need a specialized type back ?
        if ($null -ne $PipelineSnapshot -and $PipelineSnapshot.getType().Name -eq 'pscustomobject') {
            if ($Pscmdlet.ShouldProcess($PipelineSnapshot.SnapshotDb.Parent.DomainInstanceName, "Remove db snapshot $($PipelineSnapshot.SnapshotDb.Name)")) {
                try {
                    $server = Connect-SqlInstance -SqlInstance $PipelineSnapshot.SnapshotDb.Parent.DomainInstanceName -SqlCredential $Credential
                } catch {
                    Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
                }
                try {
                    if ($Force) {
                        $server.KillAllProcesses($PipelineSnapshot.SnapshotDb.Name)
                    }
                    $null = $server.Query("drop database [$($PipelineSnapshot.SnapshotDb.Name)]")
                    $status = "Dropped"
                } catch {
                    Write-Message -Level Warning -Message $_
                    $status = "Drop failed"
                }

                [PSCustomObject]@{
                    ComputerName = $PipelineSnapshot.SnapshotDb.Parent.NetName
                    InstanceName = $PipelineSnapshot.SnapshotDb.Parent.ServiceName
                    SqlInstance = $PipelineSnapshot.SnapshotDb.Parent.DomainInstanceName
                    Database    = $PipelineSnapshot.Database
                    SnapshotOf  = $PipelineSnapshot.SnapshotOf
                    Status      = $status
                }
            }
            return
        }

        # if piped value either doesn't exist or is not the proper type
        foreach ($instance in $SqlInstance) {
            Write-Message -Level Verbose -Message "Connecting to $instance"
            try {
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $Credential
            } catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }
            

            $dbs = $server.Databases
            if ($Database) {
                $dbs = $dbs | Where-Object { $Database -contains $_.DatabaseSnapshotBaseName }
            }
            
            if ($ExcludeDatabase) {
                $dbs = $dbs | Where-Object { $ExcludeDatabase -notcontains $_.DatabaseSnapshotBaseName }
            }
            
            if ($Snapshot) {
                $dbs = $dbs | Where-Object { $Snapshot -contains $_.Name }
            }
            
            if (!$Snapshot -and !$Database) {
                $dbs = $dbs | Where-Object IsDatabaseSnapshot -eq $true | Sort-Object DatabaseSnapshotBaseName, Name
            }
            

            foreach ($db in $dbs) {
                if ($db.IsAccessible -eq $false) {
                    Write-Message -Level Warning -Message "Database $db is not accessible."
                    continue
                }
                if ($Pscmdlet.ShouldProcess($server.name, "Remove db snapshot $db")) {
                    $basedb = $db.DatabaseSnapshotBaseName
                    try {
                        if ($Force) {
                            # cannot drop the snapshot if someone is using it
                            $server.KillAllProcesses($db)
                        }
                        $null = $server.Query("drop database $db")
                        $status = "Dropped"
                    } catch {
                        Write-Message -Level Warning -Message $_
                        $status = "Drop failed"
                    }
                    [PSCustomObject]@{
                        ComputerName = $server.NetName
                        InstanceName = $server.ServiceName
                        SqlInstance  = $server.DomainInstanceName
                        Database     = $db
                        SnapshotOf   = $basedb
                        Status       = $status
                    }
                }
            }
        }
    }
}