Add SASL mechanism setting (currently only PLAIN)

Author: hellmarbecker

main.py

@@ -55,6 +55,7 @@ def produce_msgs(security_protocol='SSL',
  producer = KafkaProducer(
  bootstrap_servers=hostname + ':' + port,
  security_protocol='SASL_SSL',
+ sasl_mechanism='PLAIN',
  sasl_plain_username=username,
  sasl_plain_password=password,
  value_serializer=lambda v: json.dumps(v).encode('ascii'),