Typesafe Config Environment Variables

configuration playframework akka typesafe
tysonjh picture tysonjh · Sep 12, 2013 · Viewed 9.3k times · Source

Attempting to use ${HOSTNAME} in a config file does not work! According to the documentation, config files should resolve environment variables as mentioned in the docs:

substitutions fall back to environment variables if they don't resolve in the config itself, so ${HOME} would work as you expect. Also, most configs have system properties merged in so you could use ${user.home}.

Is there a way to get hostname into the config file?

Reproduction
Add host.name=${HOSTNAME} to an application.conf file, then try and access it from anywhere. For example try adding 

Logger.info(s"Hostname is ${current.configuration.getString("host.name").getOrElse("NOT-FOUND")}")

to the Global.scala.

Environment
This was run on a RHEL6 environment where echo $HOSTNAME produces precise32 so the environment variable exists, this is not the program hostname.

Answer

tysonjh picture tysonjh · Sep 13, 2013

The solution seems to be passing in the hostname via a system property as -Dhost.name=$HOSTNAME or -Dhost.name=$(hostname). I'd imagine in windows it would be something else, but this works for *NIX environments.

Unless anyone can come up with something cleaner this will be the accepted answer.

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