Apache Stratos Communication Bus, which includes the Message Bus and the Real-time Event Bus, uses the Publish-Subscribe (pub/sub) messaging pattern to communicate among all the components (mainly the topic based pub/sub communications) in Apache Stratos. In this messaging pattern the components that send the messages are named as publishers; while, the components that receive the message are named as subscribers. The publishers group the messages into classes named topics and do not define where the published messages, which are namely events, need to be routed. Instead, the publishers maintain the topics, so that subscribers who are interested in a specific event, which is published in a topic, can subscribe to it. The actual communication process that takes place in Apache Stratos is illustrated at a high level in the diagram below.

The pub/sub communication system helps to integrate all the components in loosely coupled manner; while, providing the advantage of adding or removing components without affecting to overall system. All components need to know only one well-known-member (WKA), which is the Message Broker. As a result, this enables Apache Stratos to be configured easily. In addition, the pub/sub communication enables Apache Stratos to effortlessly scale into multi-cloud. The following diagram illustrates the actual communication process that takes place in Apache Stratos at a more detailed level, depicting the actual topics that the Stratos components subscribe to in the Message Broker.

  • No labels