Change application.conf runtime? - properties

Question

I want to set the database connection at run time for my Play project. I know that I can set a property run time with the following code:
#OnApplicationStart public class Bootstrap extends Job
{
#Override public void doJob()
{
// now set the values in the properties file
Play.configuration.setProperty("db.driver", dbDriver);
Play.configuration.setProperty("db.url", dbUrl);
Play.configuration.setProperty("db.user", dbUsername);
Play.configuration.setProperty("db.pass", dbPassword);
}
}
But when executing the code above the file is not actually changed, I think just in memory.
How can I set the database properties and force Play! to use this properties in order to connect to the right database onApplicationStart?
Thanks!
UPDATE 2012-01-29
Solution is possible via a plugin. In this plugin I have to override onConfigurationRead() and apply the properties to the configuration file at that moment. I will try to post some code as soon as I have time for this.

Answer 1

By the time you change the properties, the DB plugin is already initialized. You need to write a plugin and overwrite the onConfigurationRead() method, then put your new settings there. Paly's dbplugin will init later on.

Answer 2

I faced with the necessity of programmatically obtaining values from aws secret manager in runtime before using that values in play framework configuration. You can override initial default values from application.conf and add new.
Work for play framework v2.7.3
import com.typesafe.config.ConfigValueFactory;
import play.api.Configuration;
import play.api.inject.guice.GuiceApplicationBuilder;
import play.api.inject.guice.GuiceApplicationLoader;
public class ExtendedGuiceApplicationLoader extends GuiceApplicationLoader {
#Override
public GuiceApplicationBuilder builder(Context context) {
Configuration configuration = new Configuration(
context.initialConfiguration().underlying()
.withValue("db.default.username",
ConfigValueFactory.fromAnyRef("aws.secret.db.username"))
.withValue("db.default.password",
ConfigValueFactory.fromAnyRef("aws.secret.db.password"))
);
return super.builder(
new Context(context.environment(),
configuration,
context.lifecycle(),
context.devContext())
);
}
}
Don´t forget add this string to application.conf
play.application.loader="youpackage.ExtendedGuiceApplicationLoader"

Answer 3

Are you sure this is what you really intend to do?
Play offers the possibility to add different configurations in your application.conf
for example you could have:
db.url=mydefaulturl
%uat.db.url=uaturl
%prod.db.url=produrl
%prod1.db.url=prod1url
And then start the app with play start --%uat or play start --%prod