Externalizing Grails Datasource configuration - configuration

Question

Grails 1.x allows using external configuration files by setting the grails.config.locations directive. Is there a similar approach available for externalizing the database configuration in Datasource.groovy (without setting up JNDI)?
It would prove helpful to be able to configure DB credentials in a simple configuration file outside the application.
Thanks in advance!

Answer 1

You can use a properties file specified in the grails.config.locations as a way to externalize the datasource configuration. Below is how I typically set up a Grails project:
In my DataSource.groovy I specify this for the production environment:
....
....
production {
dataSource {
dbCreate = "update"
driverClassName = "com.myorg.jdbcDriverNotExists"
url = ""
username = ""
password = ""
}
}
....
....
I specify an external properties file in my Config.groovy:
grails.config.locations = [ "classpath:app-config.properties"]
In the properties file (stored in grails-app/conf/) I specify the actual datasource info:
dataSource.driverClassName=oracle.jdbc.OracleDriver
dataSource.url=jdbc:oracle:thin:#host:port:sid
dataSource.username=sa
dataSource.password=secret
I also use the properties file as a way to override other values that are in Config.groovy. When the app is deployed, if I have to modify the datasource info I just edit the /WEB-INF/classes/app-config.properties file and restart.

Answer 2

The answer above does not really externalize configuration. He is close, but the configuration is still residing in the application.
I would use a JVM environment var on startup of the application/server to point to a location outside the application where the external configuration resides. Read out the environment var in the config.groovy file and use it get the external configuration file. Something like this:
def extConfig = System.properties.getProperty('ENVVAR');
grails.config.locations = [ "file:${extConfig}/${appName}-config.groovy"]

Answer 3

For me this doesn't work. To get an environment variable.
Better use :
System.getenv().get("ENVVAR").toString()

Answer 4

Just put the configuration file location as following in Config.groovy file
grails.config.locations = [
"file:/yourDirectory/${appName}/${Environment.current.name}-datasource.properties",
"file:/yourDirectory/${appName}/${Environment.current.name}-config.groovy",
"classpath:${appName}-${Environment.current.name}-datasource.properties",
"classpath:${appName}-${Environment.current.name}-config.groovy"
]
And put all the details about datasource and other config values in your appropriate file. Hence you can externalize the configuration and need not restart to change values.