# Attribute Release Policy - External Groovy

Source: https://apereo.github.io/cas/development/integration/Attribute-Release-Policy-ExternalGroovy.html

Identical to inline groovy attribute definitions, except the groovy script can also be externalized to a `.groovy` file:

```json
{
  "@class" : "org.apereo.cas.services.CasRegisteredService",
  "serviceId" : "sample",
  "name" : "sample",
  "id" : 300,
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnMappedAttributeReleasePolicy",
    "allowedAttributes" : {
      "@class" : "java.util.TreeMap",
      "uid" : "file:/etc/cas/sample.groovy"
    }
  }
}
```

The `sample.groovy` script itself may have the following outline:

```groovy
import java.util.*

def run(final Object... args) {
    def (attributes,logger) = args
    logger.debug("Current attributes are {}", attributes)
    return []
}
```

> **Usage Warning**
>
> Activating this policy is not without cost, as CAS needs to evaluate the inline script, compile and run it for subsequent executions. While the compiled script is cached and should help with execution performance, as a general rule, you should avoid opting for and designing complicated scripts.

The configuration of this component qualifies to use the [Spring Expression Language](https://apereo.github.io/cas/development/configuration/Configuration-Spring-Expressions.html) syntax.

To prepare CAS to support and integrate with Apache Groovy, please [review this guide](https://apereo.github.io/cas/development/integration/Apache-Groovy-Scripting.html).