Implementation of Kafka Message Broker Driver in Userver Framework

Many modern services are implemented in the concept of microservice architecture: the application functionality is divided into parts, for each of which a separate service component is created. On the one hand, in comparison with a monolithic architecture, microservice brings a lot of convenience to the development and support of services, but on the other hand, this approach requires powerful infrastructure tools: libraries and protocols for interaction between any two parts of the service, monitoring the status of each of its components, as well as services for asynchronous event processing, produced by microservices (for example, logs, task launch requests, or events related to user actions). To deal with the latter, message queues or, more generally, platforms for streaming data processing are often used. At the moment, the most widely used service for streaming data processing is Apache Kafka. Kafka provides two main independent entities through which interaction between users and a reliable storage of distributed append-only logs takes place: producers who can send arbitrary messages to various topics, and consumers who can subscribe to read a specific set of topics. This paper will describe the implementation of the driver for Apache Kafka in userver. userver is a high-performance asynchronous Open Source C++ framework used to write microservices in Yandex.Go, as well as some services not in Yandex.