functions/Start-DbaTrace.ps1

#ValidationTags#Messaging,FlowControl,Pipeline,CodeStyle#
function Start-DbaTrace {
<#
    .SYNOPSIS
        Starts SQL Server traces
         
    .DESCRIPTION
        Starts SQL Server traces
         
    .PARAMETER SqlInstance
        The target SQL Server instance
         
    .PARAMETER SqlCredential
        Login to the target instance using alternative credentials. Windows and SQL Authentication supported. Accepts credential objects (Get-Credential)
         
    .PARAMETER Id
        A list of trace ids
         
    .PARAMETER InputObject
        Internal parameter for piping
         
    .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: Security, Trace
        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
         
    .EXAMPLE
        Start-DbaTrace -SqlInstance sql2008
         
        Starts all traces on sql2008
         
    .EXAMPLE
        Start-DbaTrace -SqlInstance sql2008 -Id 1
         
        Starts all trace with ID 1 on sql2008
         
    .EXAMPLE
        Get-DbaTrace -SqlInstance sql2008 | Out-GridView -PassThru | Start-DbaTrace
         
        Starts selected traces on sql2008
         
         
#>

    [CmdletBinding()]
    param (
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [int[]]$Id,
        [parameter(ValueFromPipeline)]
        [object[]]$InputObject,
        [switch]$EnableException
    )
    process {
        if (-not $InputObject -and $SqlInstance) {
            $InputObject = Get-DbaTrace -SqlInstance $SqlInstance -SqlCredential $SqlCredential -Id $Id
        }

        foreach ($trace in $InputObject) {
            if (-not $trace.id -and -not $trace.Parent) {
                Stop-Function -Message "Input is of the wrong type. Use Get-DbaTrace." -Continue
                return
            }

            $server = $trace.Parent
            $traceid = $trace.id
            $default = Get-DbaTrace -SqlInstance $server -Default

            if ($default.id -eq $traceid) {
                Stop-Function -Message "The default trace on $server cannot be started. Use Set-DbaSpConfigure to turn it on." -Continue
            }

            $sql = "sp_trace_setstatus $traceid, 1"

            try {
                $server.Query($sql)
                Get-DbaTrace -SqlInstance $server -Id $traceid
            }
            catch {
                Stop-Function -Message "Failure" -ErrorRecord $_ -Target $server -Continue
                return
            }
        }
    }
}