Autoscaling a distributed streaming platform in an event-driven microservice architecture

A computer program product for downscaling a streaming platform in an event-driven microservice architecture, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by one or more processors, the program instructions executable to:

• upon a consumer being removed from a consumer group that has a greatest number of consumers among consumer groups in a distributed streaming platform, determine whether a number of partitions in a topic in the distributed streaming platform is greater than a number of consumers in the consumer group;
• in response to determining that the number of the partitions is greater than the number of consumers in the consumer group, downscale the distributed streaming platform, wherein a partition consumed by the removed consumer is to be removed from the topic;
• stop message publishing to the to-be-removed partition;
• remove an assignment of the to-be-removed partition to the removed consumer;
• assign remaining messages in the to-be-removed partition to one or more remaining consumers in the consumer group and to one or more consumers in consumer groups other than the consumer group;
• determine whether all the remaining messages are consumed by the one or more remaining consumers in the consumer group and by the one or more consumers in the consumer groups other than the consumer group;
• in response to determining that all the remaining messages are consumed, delete the to-be-removed partition from the topic.