Sbt for continuous integration: print stacktrace and exit on error

Question

I'm using Sbt for continuous integration (Bamboo). I want to check all the environment variables are set or get a descriptive error message. I use the following approach:

def env(n: String) = Option(System.getenv(n)).getOrElse(throw new RuntimeException("Undefined required environment variable " + n))

val mySetting = env("REQUIRED_ENV_VAR") + "..."

Instead, I get

[error] java.lang.ExceptionInInitializerError
[error] Use 'last' for the full log.
Project loading failed: (r)etry, (q)uit, (l)ast, or (i)gnore? q

Two questions:

1. How to get full stacktrace without need to use 'last' (simple can't do it on Bamboo)?
2. How to tell sbt to exit if project loading failed instead of asking for retry etc?

Answer 1

sbt will not enable interactive mode if input stream will be "closed" with (such a hacky) trick:

cat /dev/null | sbt taskname

or if you are not able to use pipes create a shell script like this:

#!/bin/sh
sbt "$@" < /dev/null

Answer 2

In sbt v1.3.9 (and probably earlier) there is the --batch switch.

$ sbt --help
Usage: sbt [options]
  ...
  --batch             disable interactive mode
  ...