====== base-repo-get-value ======

Loads a service configuration from the repository and outputs a single value (for the given key) to STDOUT.

===== Usage =====

  base-repo-get-value SERVICE KEY

  * ''SERVICE'': A key of a service definition in the repository.
  * ''KEY'': The key for the value in the service definition to output.

===== Returns =====

Returns the value for the key in the service definition.

===== Example =====

<code bash>
#
# service must be a zone (have $ZONE set)
if [ -z "$(base-repo-get-value ${service} ZONE)" ]; then
	echo "CRITICAL: service '${service}' is no zone (ZONE not set)" >&2
	exit 1
fi
#
</code>