Open topic with navigation

# Monitor Asynchronous Actions using Event Handlers

The fetch actions sent to a connector are asynchronous. Asynchronous actions do not run immediately, but are added to a queue. This means that the person or application that sends the action does not receive an immediate response. However, you can configure the connector to call an event handler when an asynchronous action starts, finishes, or encounters an error.

You can use an event handler to:

- return data about an event back to the application that sent the action.
- write event data to a text file, to log any errors that occur.

You can also use event handlers to monitor the size of asynchronous action queues. If a queue becomes full this might indicate a problem, or that applications are making requests to ServiceNow Connector faster than they can be processed.

ServiceNow Connector can call an event handler for the following events.

OnStart | The `OnStart` event handler is called when ServiceNow Connector starts processing an asynchronous action.
OnFinish | The `OnFinish` event handler is called when ServiceNow Connector successfully finishes processing an asynchronous action.
OnError | The `OnError` event handler is called when an asynchronous action fails and cannot continue.
OnQueueEvent | The `OnQueueEvent` handler is called when an asynchronous action queue becomes full, becomes empty, or the queue size passes certain thresholds. A `QueueFull` event occurs when the action queue becomes full. A `QueueFilling` event occurs when the queue size exceeds a configurable threshold (`QueueFillingThreshold`) and the last event was a `QueueEmpty` or `QueueEmptying` event. A `QueueEmptying` event occurs when the queue size falls below a configurable threshold (`QueueEmptyingThreshold`) and the last event was a `QueueFull` or `QueueFilling` event. A `QueueEmpty` event occurs when the action queue becomes empty.

ServiceNow Connector supports the following types of event handler:

- The `TextFileHandler` writes event data to a text file.
- The `HttpHandler` sends event data to a URL.
- The `LuaHandler` runs a Lua script. The event data is passed into the script.

© 2018 Micro Focus or one of its affiliates | Send documentation feedback to Micro Focus Close Send documentation feedback To open the configured email client on this computer, open an email window. Otherwise, copy the information below to a web mail client, and send this email to swpdl.idoldocsfeedback@microfocus.com. We appreciate your feedback! Product: Topic Title: Help Topic: Feedback:

_FT_HTML5_bannerTitle.htm