SQL Agent Job Wrapper Part 3 - Handing the Errors in the Wrapper Script

function Start-SQLAgentJob
{
    <#
     .Notes
     NAME: Start-SQLAgentJob
     AUTHOR: Chris Sommer
     Version: 1.0
     CREATED: 2015-05-09

     .Synopsis
     Start a SQL Server Agent job.

     .Description
     Start a SQL Agent job and wait for its completion. This function relies on the SQL Agent to be up and running.

     .Parameter SQLServer
     SQL Server Name

     .Parameter JobName
     SQL Agent job name

     .Example
     Start-SQLAgentJob -SQLServer "localhost" -JobName "TestJob"
    #>
    [CmdletBinding()]
    param (
        [Parameter(Mandatory=$true)][string]$SQLServer ,
        [Parameter(Mandatory=$true)][string]$JobName
    )
    
    # Load the SQLPS module
    Push-Location; Import-Module SQLPS -DisableNameChecking; Pop-Location

    # ConnectionContext.Connect tests the connection to the SQLServer. This will throw an error if connection fails.
    $ServerObj = New-Object Microsoft.SqlServer.Management.Smo.Server($SQLServer)
    $ServerObj.ConnectionContext.Connect()

    # New check to ensure the JobName exists on this SQL Server
    if ( ($ServerObj.JobServer.Jobs | Where-Object {$_.Name -eq $JobName} | Select-Object -ExpandProperty Name) -ne $JobName ) {
        throw ("Job $JobName does not exist")
    }

    $JobObj = $ServerObj.JobServer.Jobs | Where-Object {$_.Name -eq $JobName}
    $JobObj.Refresh()

    # If the job is and enabled and not currently executing start it
    if ($JobObj.IsEnabled -and $JobObj.CurrentRunStatus -ne "Executing") {
        $JobObj.Start()
    }

    # Wait until the job completes. Check every second.
    do {
        Start-Sleep -Seconds 1
        # You have to run the refresh method to reread the status
        $JobObj.Refresh()
    } While ($JobObj.CurrentRunStatus -eq "Executing")

    # Get the run duration by adding all of the step durations
    $RunDuration = 0
    foreach($JobStep in $JobObj.JobSteps)     {
        $RunDuration += $JobStep.LastRunDuration
    }

    # If the job succeeded return the job object, otherwise throw an error.
    if ($JobObj.LastRunOutcome -eq "Succeeded") {
        $JobObj | select Name,CurrentRunStatus,LastRunOutcome,LastRunDate,@{Name="LastRunDurationSeconds";Expression={$RunDuration}}
    } else {
        $JobResult = $JobObj.LastRunOutcome
        throw ("Job '$JobName' LastRunOutcome = '$JobResult'")
    }
}

Set-StrictMode -Version 2.0
$error.Clear()
$ErrorActionPreference = "Stop"

try {
    # Setup pathing and environment based on the script location
    $Invocation = (Get-Variable MyInvocation -Scope 0).Value
    $ScriptLocation = Split-Path $Invocation.MyCommand.Path
 
    # Load the Start-SQLAgentJob cmdlet
    . "$ScriptLocation\Start-SQLAgentJob.ps1"
 
    # Set a couple variables for testing and call the cmdlet
    $SQLServer = "localhost\inst1"
    $JobName = "TestJob"
    Start-SQLAgentJob -SQLServer $SQLServer -JobName $JobName
} catch {
    $error[0]
    throw $error[0]
    # Exit with error code of 1 on any failure
    $host.SetShouldExit(1) 
}