functions/Get-DbaRegisteredServer.ps1

function Get-DbaRegisteredServer {
    <#
        .SYNOPSIS
            Gets list of SQL Server objects stored in SQL Server Central Management Server (CMS).
 
        .DESCRIPTION
            Returns an array of servers found in the CMS.
 
        .PARAMETER SqlInstance
            SQL Server name or SMO object representing the SQL Server to connect to.
 
        .PARAMETER SqlCredential
            Allows you to login to servers using SQL Logins instead of Windows Authentication (AKA Integrated or Trusted). To use:
 
            $scred = Get-Credential, then pass $scred object to the -SqlCredential parameter.
 
            Windows Authentication will be used if SqlCredential is not specified. SQL Server does not accept Windows credentials being passed as credentials.
 
            To connect as a different Windows user, run PowerShell as that user.
 
        .PARAMETER Group
            Specifies one or more groups to include from SQL Server Central Management Server.
 
        .PARAMETER ExcludeGroup
            Specifies one or more Central Management Server groups to exclude.
     
        .PARAMETER ExcludeCmsServer
            Deprecated, now follows the Microsoft convention of not including it by default. If you'd like to include the CMS Server, use -IncludeSelf
 
        .PARAMETER IncludeSelf
            If this switch is enabled, the CMS server itself will be included in the results, along with all other Registered Servers.
 
        .PARAMETER ResolveNetworkName
            If this switch is enabled, the NetBIOS name and IP address(es) of each server will be returned.
     
        .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
            Author: Bryan Hamby (@galador)
            Tags: RegisteredServer, CMS
 
            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/Get-DbaRegisteredServer
 
        .EXAMPLE
            Get-DbaRegisteredServer -SqlInstance sqlserver2014a
 
            Gets a list of servers from the CMS on sqlserver2014a, using Windows Credentials.
     
        .EXAMPLE
            Get-DbaRegisteredServer -SqlInstance sqlserver2014a -IncludeSelf
 
            Gets a list of servers from the CMS on sqlserver2014a and includes sqlserver2014a in the output results.
 
        .EXAMPLE
            Get-DbaRegisteredServer -SqlInstance sqlserver2014a -SqlCredential $credential | Select-Object -Unique -ExpandProperty ServerName
 
            Returns only the server names from the CMS on sqlserver2014a, using SQL Authentication to authenticate to the server.
 
        .EXAMPLE
            Get-DbaRegisteredServer -SqlInstance sqlserver2014a -Group HR, Accounting
 
            Gets a list of servers in the HR and Accounting groups from the CMS on sqlserver2014a.
 
        .EXAMPLE
            Get-DbaRegisteredServer -SqlInstance sqlserver2014a -Group HR\Development
 
            Returns a list of servers in the HR and sub-group Development from the CMS on sqlserver2014a.
    #>

    [CmdletBinding()]
    param (
        [parameter(Mandatory, ValueFromPipeline)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [Alias("Groups")]
        [object[]]$Group,
        [object[]]$ExcludeGroup,
        [switch]$IncludeSelf,
        [switch]$ExcludeCmsServer,
        [switch]$ResolveNetworkName,
        [switch][Alias('Silent')]$EnableException
    )
    begin {
        function Find-CmsGroup {
            [OutputType([object[]])]
            [cmdletbinding()]
            param(
                $CmsGrp,
                $Base = $null,
                $Stopat
            )
            $results = @()
            foreach ($el in $CmsGrp) {
                if ($null -eq $Base -or [string]::IsNullOrWhiteSpace($Base) ) {
                    $partial = $el.name
                }
                else {
                    $partial = "$Base\$($el.name)"
                }
                if ($partial -eq $Stopat) {
                    return $el
                }
                else {
                    foreach ($elg in $el.ServerGroups) {
                        $results += Find-CmsGroup -CmsGrp $elg -Base $partial -Stopat $Stopat
                    }
                }
            }
            return $results
        }
        
        $defaults = @()
        if ($ResolveNetworkName) {
            $defaults += 'ComputerName', 'FQDN', 'IPAddress'
        }
        $defaults += 'Name', 'ServerName', 'Description', 'ServerType', 'SecureConnectionString'
        
    }
    
    process {
        if (Test-FunctionInterrupt) { 
            return 
        }

        $servers = @()
        foreach ($instance in $SqlInstance) {
            try {
                $cmsStore = Get-DbaRegisteredServersStore -SqlInstance $instance -SqlCredential $SqlCredential -EnableException
            }
            catch {
                Stop-Function -Message "Cannot access Central Management Server '$instance'." -ErrorRecord $_ -Continue
            }

            if (Test-Bound -ParameterName ExcludeGroup) {
                $Group = ($cmsStore.DatabaseEngineServerGroup.ServerGroups | Where-Object Name -notin $ExcludeGroup).Name
            }

            if ($Group) {
                foreach ($currentGroup in $Group) {
                    $cms = Find-CmsGroup -CmsGrp $cmsStore.DatabaseEngineServerGroup.ServerGroups -Stopat $currentGroup
                    if ($null -eq $cms) {
                        Write-Message -Level Output -Message "No groups found matching that name on instance '$instance'."
                        continue
                    }
                    $servers += ($cms.GetDescendantRegisteredServers())
                }
            }
            else {
                $cms = $cmsStore.DatabaseEngineServerGroup
                $servers += ($cms.GetDescendantRegisteredServers())
            }
            
            # Close the connection, otherwise using it with the ServersStore will keep it open
            $cmsStore.ServerConnection.Disconnect()
        }
        
        foreach ($server in $servers) {
            Add-Member -Force -InputObject $server -MemberType NoteProperty -Name ComputerName -Value $null
            Add-Member -Force -InputObject $server -MemberType NoteProperty -Name FQDN -Value $null
            Add-Member -Force -InputObject $server -MemberType NoteProperty -Name IPAddress -Value $null
            
            if ($ResolveNetworkName) {
                try {
                    $lookup = Resolve-DbaNetworkName $server.ServerName -Turbo
                    Add-Member -Force -InputObject $server -MemberType NoteProperty -Name ComputerName -Value $lookup.ComputerName
                    Add-Member -Force -InputObject $server -MemberType NoteProperty -Name FQDN -Value $lookup.FQDN
                    Add-Member -Force -InputObject $server -MemberType NoteProperty -Name IPAddress -Value $lookup.IPAddress
                }
                catch {
                    try {
                        $lookup = Resolve-DbaNetworkName $server.ServerName
                        Add-Member -Force -InputObject $server -MemberType NoteProperty -Name ComputerName -Value $lookup.ComputerName
                        Add-Member -Force -InputObject $server -MemberType NoteProperty -Name FQDN -Value $lookup.FQDN
                        Add-Member -Force -InputObject $server -MemberType NoteProperty -Name IPAddress -Value $lookup.IPAddress
                    }
                    catch {}
                }
            }
            
            Add-Member -Force -InputObject $server -MemberType ScriptMethod -Name ToString -Value { $this.ServerName }
            Select-DefaultView -InputObject $server -Property $defaults
        }
        
        if ($IncludeSelf -and $servers) {
            $self = $servers[0].PsObject.Copy()
            $self | Add-Member -MemberType NoteProperty -Name Name -Value "CMS Instance" -Force
            $self.ServerName = $instance
            $self.Description = $null
            $self.SecureConnectionString = $null
            Select-DefaultView -InputObject $self -Property $defaults
        }
    }
    end {
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -Parameter ExcludeCmsServer
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -Alias Get-DbaRegisteredServerName
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -Alias Get-SqlRegisteredServerName
    }
}