functions/Set-DbaDbMirror.ps1

#ValidationTags#Messaging,FlowControl,Pipeline,CodeStyle#
function Set-DbaDbMirror {
    <#
    .SYNOPSIS
        Sets properties of database mirrors.
 
    .DESCRIPTION
        Sets properties of database mirrors.
 
    .PARAMETER SqlInstance
        The target SQL Server instance or instances. This can be a collection and receive pipeline input to allow the function
        to be executed against multiple SQL Server instances.
 
    .PARAMETER SqlCredential
        Login to the target instance using alternative credentials. Windows and SQL Authentication supported. Accepts credential objects (Get-Credential)
 
    .PARAMETER Database
        The target database.
 
    .PARAMETER Partner
        Sets the partner fqdn.
 
    .PARAMETER Witness
        Sets the witness fqdn.
 
    .PARAMETER SafetyLevel
        Sets the mirroring safety level.
 
    .PARAMETER State
        Sets the mirror state.
 
    .PARAMETER InputObject
        Allows piping from Get-DbaDatabase.
 
    .PARAMETER WhatIf
        Shows what would happen if the command were to run. No actions are actually performed.
 
    .PARAMETER Confirm
        Prompts you for confirmation before executing any changing operations within the command.
 
    .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: Mirror, HA
        Author: Chrissy LeMaire (@cl), netnerds.net
 
        Website: https://dbatools.io
        Copyright: (c) 2018 by dbatools, licensed under MIT
        License: MIT https://opensource.org/licenses/MIT
 
    .LINK
        https://dbatools.io/Set-DbaDbMirror
 
    .EXAMPLE
        PS C:\> Set-DbaDbMirror -SqlInstance sql2005 -Database dbatools -Partner TCP://SQL2008.ad.local:5374
 
        Prompts for confirmation then sets the partner to TCP://SQL2008.ad.local:5374 for the database "dbtools"
 
    .EXAMPLE
        PS C:\> Set-DbaDbMirror -SqlInstance sql2005 -Database dbatools -Witness TCP://SQL2012.ad.local:5502 -Confirm:$false
 
        Does not prompt for confirmation and sets the witness to TCP://SQL2012.ad.local:5502 for the database "dbtools"
 
    .EXAMPLE
        PS C:\> Get-DbaDatabase -SqlInstance sql2005 | Out-GridView -PassThru | Set-DbaDbMirror -SafetyLevel Full -Confirm:$false
 
        Sets the safety level to Full for databases selected from a grid view. Does not prompt for confirmation.
 
    .EXAMPLE
        PS C:\> Set-DbaDbMirror -SqlInstance sql2005 -Database dbatools -State Suspend -Confirm:$false
 
        Does not prompt for confirmation and sets the state to suspend for the database "dbtools"
 
    #>

    [CmdletBinding(SupportsShouldProcess, ConfirmImpact = 'High')]
    param (
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [string[]]$Database,
        [string]$Partner,
        [string]$Witness,
        [ValidateSet('Full', 'Off', 'None')]
        [string]$SafetyLevel,
        [ValidateSet('ForceFailoverAndAllowDataLoss', 'Failover', 'RemoveWitness', 'Resume', 'Suspend', 'Off')]
        [string]$State,
        [parameter(ValueFromPipeline)]
        [Microsoft.SqlServer.Management.Smo.Database[]]$InputObject,
        [switch]$EnableException
    )
    process {
        if ((Test-Bound -ParameterName SqlInstance) -and (Test-Bound -Not -ParameterName Database)) {
            Stop-Function -Message "Database is required when SqlInstance is specified"
            return
        }
        foreach ($instance in $SqlInstance) {
            $InputObject += Get-DbaDatabase -SqlInstance $instance -SqlCredential $SqlCredential -Database $Database
        }

        foreach ($db in $InputObject) {
            try {
                if ($Partner) {
                    if ($Pscmdlet.ShouldProcess($db.Parent.Name, "Setting partner on $db")) {
                        # use t-sql cuz $db.Alter() doesnt always work against restoring dbs
                        $db.Parent.Query("ALTER DATABASE $db SET PARTNER = N'$Partner'")
                    }
                } elseif ($Witness) {
                    if ($Pscmdlet.ShouldProcess($db.Parent.Name, "Setting witness on $db")) {
                        $db.Parent.Query("ALTER DATABASE $db SET WITNESS = N'$Witness'")
                    }
                }

                if ($SafetyLevel) {
                    if ($Pscmdlet.ShouldProcess($db.Parent.Name, "Changing safety level to $SafetyLevel on $db")) {
                        $db.Parent.Query("ALTER DATABASE $db SET PARTNER SAFETY $SafetyLevel")
                        # $db.MirroringSafetyLevel = $SafetyLevel
                    }
                }

                if ($State) {
                    if ($Pscmdlet.ShouldProcess($db.Parent.Name, "Changing mirror state to $State on $db")) {
                        $db.ChangeMirroringState($State)
                        $db.Alter()
                        $db
                    }
                }
            } catch {
                Stop-Function -Message "Failure" -ErrorRecord $_
            }
        }
    }
}