# OnQueueEvent

ServiceNow Connector generates an event when an asynchronous action queue becomes full, becomes empty, or the queue size passes certain thresholds. The `OnQueueEvent` parameter specifies the name of the handler to use to handle these events.

- A `QueueFull` event occurs when the action queue becomes full.
- A `QueueFilling` event occurs when the queue size exceeds the value of QueueFillingThreshold and the last event was a `QueueEmpty` or `QueueEmptying` event.
- A `QueueEmptying` event occurs when the queue size falls below the value of QueueEmptyingThreshold and the last event was a `QueueFull` or `QueueFilling` event.
- A `QueueEmpty` event occurs when the action queue becomes empty.

The name that you specify must represent a section in the configuration file that contains the LibraryName parameter and any other settings for the event handler. For example:

    [ActionName]
    OnQueueEvent=MyHandler
    QueueFillingThreshold=0.7
    QueueEmptyingThreshold=0.4

    [MyHandler]
    LibraryName=LuaHandler
    LuaScript=./handle_queue_event.lua

In the example above, the Lua script might respond to the events by sending a notification to an administrator.

An event contains the following information:

`queueEventType` | The type of event, for example `QueueFull` or `QueueFilling`.
`maxQueueSize` | The maximum size of the queue.
`queueSize` | The current size of the queue (not present for `QueueEmpty` events).

Type: | String
Default: |
Required: | No
Configuration Section: | ActionName or Actions where ActionName is the name of an asynchronous action.
Example: | `OnQueueEvent=EventHandler`
See Also: | OnStart OnFinish OnError QueueEmptyingThreshold QueueFillingThreshold

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