public String getClientId() {
    String clientId = (String) get(ConsumerConfig.CLIENT_ID_CONFIG);
    if (StringUtils.isBlank(clientId)) {
      throw new SamzaException("client Id is not set for consumer for system=" + systemName);
    }
    return clientId;
  }
Create kafka consumer configs, based on the subset of global configs.
@param config application config
@param systemName system name
@param clientId client id provided by the caller
@return KafkaConsumerConfig
samza-kafka/src/main/java/org/apache/samza/config/KafkaConsumerConfig.java