Splitting resources.groovy configuration in Grails applications

Splitting resources.groovy configuration in Grails applications

Table Of Contents

• 1. Introduction
  
• 2. How to split resources.groovy
• 3. Import external bean file

1. Introduction:

In grails, when our resources.groovy file is growing then it is better to split some logical bean configuration with a separate file and import that file in resources.groovy.  For this, Grails provides a neat way to specify Spring bean definitions with its custom Beans DSL by using importBeans or loadBeans.

2. How to split resources.groovy

You can simply create resources file under  "grails-app/conf/spring/" package: e.g

firstBean.groovy:

beans {
  beanConfiguration: yourBeanConfiguration
}

3. Import external bean file

Grails provide importBeans or loadBeans to import custom external bean file which can be done inside resources.groovy as bellow:

beans = { 
  importBeans('file:grails-app/conf/spring/firstBean.groovy') 
}

The problem is that this seems to work, but only if you run the application via  grails run-app with the embedded servlet container.

As soon we create a WAR file and deploy it into tomcat we are getting into trouble. The problem is Spring Bean Configuration file is moved on the different folder in tomcat "WEB-INF/classes/spring/" so we can get file-not-found-exception.

In order to resolve this problem, we need to locate custom resource path in resources.groovy.

def loadFromFile = { name ->
        importBeans("file:grails-app/conf/spring/"+name)
    }

    def loadFromWar = { name ->
        def resource = application.parentContext.getResource("WEB-INF/classes/spring/"+name)
        loadBeans(resource)
    }
    def loadResource = application.isWarDeployed() ? loadFromWar : loadFromFile

    loadResource "firstBean.groovy"
    loadResource "secondBean.groovy"

Here if the application is running via grails run-app then it will use the path "grails-app/conf/spring/". And if it is via external tomcat with deploying the WAR file then it uses the path "WEB-INF/classes/spring/".

Note: Be sure that your resource file is packaged on WAR with the right path.