An evolving architecture

massimiliano mazzarolo

Over the past few years, constant changes in software development techniques, frameworks and tools led us to rethink how our architecture might evolve over time to sustain changes and support demand from business.

Massimiliano Mazzarolo is the Chief Architect here at lm group. Despite 25 years of experience he’s still obsessed with software architecture and development. He lives in Milan (Italy).

We have a long story behind, and the way the’ systems have been built has changed over the years. In the beginning we had a monolithic architecture with few big applications running on VM; today, with more than 300 microservices active, the landscape is totally different.

For this reason, we started to look at the architecture with a different perspective, segregating responsibilities in domains. We were heavily influenced by the Domain Oriented Microservice Architecture concept introduced by Uber, and we’re constantly evolving our services to be accommodated in the following way.

We decided to extensively adopt the API gateway pattern by introducing gateways at the boundaries of every domain; although we currently support REST API and message-driven communications, in the future we might extend the range of supported protocols.

architecture kafka domain service api gateway
An overview of our domains architecture

We have two distinct technologies to manage event-driven communications today, to leverage at best different characteristics.

To manage communication between different domains we use Apache Kafka: a formal contract for domain events is established by using avro schema stored into a Schema Registry. In this way, long-term storage of events is both safe and secure, and we can leverage all the well-known characteristics of Kafka.

To manage communication inside the same domain we use RabbitMQ; in this case, contracts are managed by establishing a partnership between the teams responsible for keeping the communication healthy. RabbitMQ has plenty of useful routing capabilities available out of the box and a rich integration with our core framework - app framework - that is based on Spring Boot.

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This is the second in a series of articles where we talk about our pink world. If you want to discover more, read:

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