# Datasource Service Events

These events occur around the lifecycle of datasources and the datasource service.

* [`onDatasourceServiceStartup`](#onDatasourceServiceStartup)
* [`onDatasourceServiceShutdown`](#onDatasourceServiceShutdown)
* [`onDatasourceStartup`](#onDatasourceStartup)
* [`onDatasourceConfigLoad`](#onDatasourceConfigLoad)

## onDatasourceServiceStartup

This event is triggered immediately after the datasource service has started. You could use this event to register custom datasources after the service has started, for example.

| Data Key          | Type       | Description                               |
| ----------------- | ---------- | ----------------------------------------- |
| DatasourceService | Java class | Instance of the BoxLang DatasourceService |

### Example

```js
class myDatasourceListener {
    function onDatasourceServiceStartup( struct data ) {
        println("Datasource service is starting up");
        println( data.datasourceService.getNames() );
    }
}
```

## onDatasourceServiceShutdown

This event is triggered immediately prior to datasource service shutdown. You could use this event to perform any cleanup on custom datasources, for example.

| Data Key          | Type       | Description                               |
| ----------------- | ---------- | ----------------------------------------- |
| DatasourceService | Java class | Instance of the BoxLang DatasourceService |

### Example

```js
class myDatasourceListener {
    function onDatasourceServiceShutdown( struct data ) {
        println("Datasource service is shutting down");
        println( data.datasourceService.getNames() );
    }
}
```

## onDatasourceStartup

This event is triggered immediately prior to datasource startup. You can listen to this event to perform any last-minute configuration tweaks on the datasource before it is started.

| Data Key     | Type       | Description                                                                                 |
| ------------ | ---------- | ------------------------------------------------------------------------------------------- |
| `name`       | String     | Datasource name                                                                             |
| `properties` | Struct     | Datasource configuration properties                                                         |
| `config`     | Java class | Instance of the DatasourceConfig class, which stores all configuration for this datasource. |

### Example

```js
class myDatasourceListener {
    function onDatasourceStartup( struct data ) {
        println("Datasource [#data.name#] is starting up!");
        println( data.properties );
    }
}
```

## onDatasourceConfigLoad

This event is triggered immediately prior to datasource configuration load. You can use this event to modify the datasource configuration prior to processing

| Data Key     | Type   | Description                         |
| ------------ | ------ | ----------------------------------- |
| `name`       | String | Datasource name                     |
| `properties` | Struct | Datasource configuration properties |

### Example

```js
class myDatasourceListener {
    function onDatasourceConfigLoad( struct data ) {
        println("Datasource [#data.name#] is configuring!");
        println( data.properties );
    }
}
```