Configafe Config Environment Variables

Question

Trying to use ${HOSTNAME} in the configuration file does not work! According to the documentation, configuration files should allow environment variables, as indicated in the documents:

Lookups

return to environment variables if they are not resolved in the configuration itself, so $ {HOME} will work as you expect. In addition, most configurations combine system properties, so you can use $ {user.home}.

Is there a way to get the hostname in the configuration file?

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

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

at Global.scala .

Environment
This was done in the RHEL6 environment, where echo $HOSTNAME creates precise32 , so there is an environment variable, it is not a hostname program.

Answer 1

The solution seems to pass the host name through the system property as -Dhost.name=$HOSTNAME or -Dhost.name=$(hostname) . I would suggest that in windows this will be something else, but this works for NIX environments.

If anyone can come up with something cleaner, this will be an accepted answer.

Answer 2

This probably doesn't work because $HOSTNAME apparently not an environment variable:

 jamesw@T430s:~$ echo $HOSTNAME T430s jamesw@T430s:~$ export|grep HOSTNAME jamesw@T430s:~$ 

So it must be some other special bash thing.

Answer 3

You should see if the call to System.getenv("HOSTNAME") returns a nonzero value. If not, HOSTNAME not an env variable according to the java environment, which is important for matching with the configuration property in config-config. I tried this with a HOSTNAME , and although I could repeat it in bash, it was not available in java as a replacement for env. I changed it to USER and everything worked as expected.