Q: ReactiveMongo configuration on Heroku using Config Vars I have ReactiveMongo happily working with PlayFramework ("org.reactivemongo" %% "play2-reactivemongo" % "0.12.4") with the mongodb.uri configuration in my application.conf file.  This has been pushed up and works correctly with Heroku.  I also have an application.prod.conf working.
I am now trying to roll this out onto a Heroku Pipeline, with two upstream servers (so that prevents me continuing to use the application.prod.conf mechanism), and want to configure the mongodb.uri from Heroku's Config Vars.  I am not sure how to get ReactiveMongo to look for environment variables instead of application.conf settings.
I also don't know how to specify the uri to use in the code otherwise I could just use something like val uri = scala.util.Properties.envOrElse("mongodb_uri", "some-value-here").  It seems to happen by ReactiveMongo magic (under the hood).
Or is there a different way to do it?!?!
Can someone please advise?

A: You can put environment variables in your application.prod.conf. For example:
mongodb_uri = ${?MONGODB_URL}

For more information see the Play documentation on production configuration.
