GRAILS DATABASE AND CONFIG PROPERTIES EXTERNALIZATION

In Grails' DataSource descriptor file located at grails-app/conf/DataSource.groovy.

This file contains the dataSource definition which includes the database settings like

driverClassName ,username ,password ,url  etc.....

Since Grails' DataSource definition is "environment aware", so you can do it like:

local {

                              dataSource {

                                             dbCreate = "update" // one of 'create', 'create-drop','update'

                                             url = "jdbc:mysql://localhost/dbname"                   

                                             username = "username"

                                             password = "password"

                              }

               }

production {

                              dataSource {

                                             dbCreate = "update" // one of 'create', 'create-drop','update'

                                             url = "jdbc:mysql://hostname/dbname"                  

                                             username = "username"

                                             password = "password"

                              }

               }

We can externalize these settings by creating the separate property file to set above parameter.

Below are the steps I follow to externalize the database parameter in grails application.

Step 1)

Set one System property which is path to your externalize property file or dir

                          JAVA_OPTS="$JAVA_OPTS -DextConfigDir=/path/to/ext/prop"

Step 2)

                       In Config.groovy add the below chunk of code. This will search for config files that get
                       merged into the main config.

                              def extConfig = System.properties.getProperty('extConfigDir')

                              grails.config.locations = ["file:${userHome}/.grails/${appName}-config.groovy"]

                              if (extConfig) {

                                             grails.config.locations << "file:${extConfig}/Config.properties"

                              }

                 

Step 3)

                    Creating the externalize property file.
                    Remove the datasource properties from DataSource.groovy and set this properties in
                    Config.properties mentioned below

                       Ex: - In DataSource.groovy

                              local {

                                             dataSource {

                                                            url = "jdbc:mysql://localhost/dbname"                   

                                                            username = "username"

                                                            password = "password"

                                             }

                              }

                              The Exteralize Config.properties file will be

                              dataSource.url=jdbc:mysql://localhost/dbname

                              dataSource.username=username

                              dataSource.password=password

 In this way we can externalize the data source as well as Config.groovy properties