Creating Self-Deleting Scheduled Tasks from a Custom Command

Question

I have a PowerShell Script (being run in a Custom Command) that creates a Scheduled Task that runs another Custom Command but I want the resulting Scheduled Task to delete itself once it has run. Essentially, I'm creating a schedulable Custom Command workflow that's fire-and-forget.

What is the safest way to do this? I don't want to rely on a batch job to clear out said Tasks from a Container.

Some example code I have been playing with:

$UserDisplayName = "%displayName%"
$UserObjectDN = "%distinguishedName%"
$ScheduledDate = [datetime]::ParseExact("%param-ScheduledDateTime%","dd/MM/yyyy HH:mm:ss",$null)
$TasksContainerDN = "CN=Once-Off,CN=Scheduled Tasks,CN=Configuration Objects,CN=Adaxes Configuration,CN=Adaxes" #Or Perhaps $Context.GetWellKnownContainerPath("ScheduledTasks")
$CustomCommandID = "{00000000-0000-0000-0000-000000000000}"
$CustomCommandDN = "CN=My Custom Command,CN=Custom Commands,CN=Configuration Objects,CN=Adaxes Configuration,CN=Adaxes"
$CustomCommandParamValues = @{
    MyParamOne = "%param-MyParamOne%"
    MyParamTwo = "%param-MyParamTwo%"
}

$scheduledTasksContainer = $Context.BindToObject($TasksContainerDN)
$scheduledTasksContainer.Filter = @("adm-ScheduledTask")
$existingTaskFound = $false
foreach($scheduledTask in $scheduledTasksContainer)
{
    if($scheduledTask.TaskName -eq "My Custom Command - $($UserDisplayName) %objectGUID%") {
        $existingTaskFound = $true
        $Context.Cancel("$($UserDisplayName) is already scheduled for My Custom Command.")
    }
}

if(!$existingTaskFound) {
    $task = $scheduledTasksContainer.Create("adm-ScheduledTask", "CN=My Custom Command - $($UserDisplayName) %objectGUID%")

    $task.ObjectType = "user"
    $task.Description = "My Custom Command - $($UserDisplayName) %objectGUID% (Created by %adm-InitiatorFullName%)"
    $task.Disabled = $False
    $task.ExecutionMoment = "ADM_BUSINESSRULEEXECMOMENT_BEFORE"
    $task.OperationType = "none"

    $recurrencePattern = $task.GetRecurrencePattern()
    $recurrencePattern.RecurrenceType = "ADM_RECURRENCEPATTERNTYPE_ONCE"
    $recurrencePattern.PatternStartDateTime = $ScheduledDate
    $task.SetRecurrencePattern($recurrencePattern)
    $task.DeleteTaskAfterExecution = $True
    $task.SetInfo()

    $actionsAndConditions = $task.ConditionedActions.Create()
    $actionsAndConditions.ConditionsLogicalOperation = "ADM_LOGICALOPERATION_AND"
    $actionsAndConditions.SetInfo()

    $action = $actionsAndConditions.Actions.CreateEx("adm-CustomCommandAction")
    $action.ExecutionOptions = "ADM_ACTIONEXECUTIONOPTIONS_SYNC"
    $customCommand = $Context.BindToObjectByDN($CustomCommandDN)
    $arguments = $customCommand.CreateArguments()
    foreach($Parameter in $CustomCommandParamValues.Keys) {
        $arguments.SetParameterValue($Parameter, $CustomCommandParamValues.Item($Parameter))
    }
    $customCommandAction = $action.GetAction()
    $customCommandAction.CustomCommandId = $CustomCommandID
    $customCommandAction.Arguments = $arguments
    $action.SetAction($customCommandAction)
    $action.SetInfo()
    $actionsAndConditions.Actions.Add($action)

    $task.ConditionedActions.Add($actionsAndConditions)

    $scopeItem = $task.ActivityScopeItems.Create()
    $scopeItem.BaseObject = $Context.BindToObject("Adaxes://$($UserObjectDN)")
    $scopeItem.Type = "ADM_SCOPEBASEOBJECTTYPE_CONTAINER "
    $scopeItem.Inheritance = "ADS_SCOPE_BASE"
    $scopeItem.Exclude = $False
    $scopeItem.SetInfo()

    $task.ActivityScopeItems.Add($scopeItem)

    $task.SetInfo()
}

Answer 1

Hello,

The correct way to create a scheduled task that will run once and then delete itself is by setting the DeleteTaskAfterExecution property of the task to $True which you already have in your script. As per our check, the only thing you need to change in the script is replacing this line

$scheduledTasksContainer = $Context.BindToObject($TasksContainerDN)

with the below one

$scheduledTasksContainer = $Context.BindToObjectByDN($TasksContainerDN)

The update is required because method BindToObject requires an ADS path as parameter, not a distinguished name.

If you have issues with the script, please, provide all the possible details and live examples.

Comments

Strange, as they tasks weren't deleting after execution. Thank you for the code review.