private string InterpretValueExpression(string expression)
{
return(_variableReference.Replace(expression, match =>
{
var variable = match.Groups[1].Value;
var valueOpt = _configuration.GetOptional(variable);
if (!valueOpt.IsPresent)
{
Log.Warn("Could not find configuration key '" + variable + "'!");
}
return valueOpt.OrDefault();
}));
}