How to specify config file with sbt start in Play application?

Question

I have what I assume to be a common use case for developing and deploying a Play 2.3.6 application:

• In development, I run sbt run and the application uses application.conf as expected.
• In production I would like to use sbt start and specify the config file, production.conf, which resides in the same directory as the dev config file (which is <project root>/conf/)

Following the instructions under the "Specifying alternative configuration file" heading on the official docs page, like so:

$ sbt start -Dconfig.file=/full/path/to/project/conf/production.conf

The application starts without error, but I can inspect the web application and see that it is loading my application.conf development values, not my production values found in production.conf.

I also tried the suggested approach:

$ sbt start -Dconfig.resource=production.conf

And the server fails to start with error:

[error] com.typesafe.config.ConfigException$IO: production.conf: java.io.IOException: resource not found on classpath: production.conf

Has anyone else figured out how to do this correctly?

Answer 1

After a few wasted hours, I figured it out. Using quotes as follows passes the parameter correctly:

$ sbt "start -Dconfig.resource=production.conf"

Also, if you need to specify the port number, make sure it comes after the config option, otherwise it will be ignored:

$ sbt "start -Dconfig.resource=production.conf 9001"