# DataSource configuration reference: Introduction

The following pages define the configuration items that you can use to configure a [DataSource application](index.md) (such as [Liberator](../liberator/index.md), [Transformer](../transformer/index.md) or an [Integration Adapter](../platform-architecture/putting-data-into-the-platform.md)).

For an overview of how configuration works see [Features and concepts of DataSource configuration](datasource-datasource-configuration.md).

To find out about the format of configuration items, see the [DataSource Configuration Syntax Reference](datasource-configuration-syntax.md).

There’s a page (or sometimes more) for each area of configuration (peer connections, data services, logging, and so on), listing all the configuration items that are available for that area. Most configuration items can be used in both C-based and Java-based DataSource applications, including Liberator and Transformer.

## Configuration file locations

If you are developing a DataSource application:

* The application’s default configuration goes in: `blade/DataSource/etc/datasource.conf`
* The application’s default overriding configuration goes in: `blade/overrides/__datasource-name__/etc/datasource.conf`

If you are deploying a kit to a Deployment Framework, override the application’s default DataSource settings in one of the Deployment Framework locations below:

* Liberator: `global_config/overrides/servers/Liberator/etc/...`
* Transformer: `global_config/overrides/servers/Transformer/etc/...`
* Other DataSources: `global_config/overrides/__datasource__/datasource.conf`

For how to do this, see the How Can I... pages listed below under [See also](#see-also).

## Mandatory items and default values

If a configuration item or an option within an item has a default value, the item/option is optional and if you don’t specify it, its default value will apply.

If the default is shown as [none], the item/option is mandatory (unless otherwise indicated) - you must specify it in your configuration. For example, the [`service-name`](datasource-data-services-configuration.md#service-name) and [`add-source-group`](datasource-data-services-configuration.md#add-source-group) options of the [`add-data-service`](datasource-data-services-configuration.md#add-data-service) item have no default, so if you define a data service, it must at least have a name and a single `add-source-group`:

```
add-data-service
   service-name MyDataService
   add-source-group
      ...
   add-source-group
end-data-service
```

## Links to the DataSource configuration reference pages

* [DataSource Configuration syntax reference](datasource-configuration-syntax.md)
* [Field definition format](datasource-field-definition-format.md)
* [Run-time environment](datasource-run-time-environment-configuration.md)
* [DataSource peers](datasource-datasource-peers-configuration-part-1.md)
* [Data services](datasource-data-services-configuration.md)
* [Name mapping](datasource-name-mapping-configuration.md)
* [Logging](datasource-logging-configuration.md)
* [Embedded JVM](datasource-java-jvm-configuration.md)
* [DataSource Secure Sockets Layer (SSL)](datasource-datasource-secure-sockets-layer-ssl-configuration.md)
* [KeyMaster](datasource-keymaster-configuration.md)
* [DataSource monitoring](datasource-datasource-monitoring-configuration-part-1.md)
* [Latency chains](datasource-latency-chains-configuration.md)

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**<a name="see-also"></a>See also:**

* [Deployment Framework Structure](../deployment-framework/cdf-deployment-framework-structure.md)
* How Can I... [Create a custom blade](../deployment-framework/cdf-create-a-custom-blade.md)
* How Can I... [Package a custom blade](../deployment-framework/cdf-package-a-custom-blade.md)
* How Can I... [Deploy a custom blade](../deployment-framework/cdf-deploy-a-custom-blade.md)
* How Can I... [Change a blade’s configuration](../deployment-framework/cdf-change-a-blades-configuration.md)
* Deployment Framework Reference: [Configuration macros and items](../deployment-framework/cdf-configuration-macros-and-items.md)