Microservices.io is brought to you by Chris Richardson. Experienced software architect, author of POJOs in Action, the creator of the original CloudFoundry.com, and the author of Microservices patterns.
Chris helps clients around the world adopt the microservice architecture through consulting engagements, and training classes and workshops.
Chris offers numerous resources for learning the microservice architecture.
Chris teaches comprehensive workshops and training classes for executives, architectures and developers to help your organization use microservices effectively. Learn how to avoid the pitfalls of adopting microservices and learn essential topics, such as service decomposition and design and Kubernetes.
Want to see an example? Check out Chris Richardson's example applications. See code
Engage Chris to create a microservices adoption roadmap and help you define your microservice architecture,
Use the Eventuate.io platform to tackle distributed data management challenges in your microservices architecture.
Eventuate is Chris's latest startup. It makes it easy to use the Saga pattern to manage transactions and the CQRS pattern to implement queries.
Join the microservices google group
A service command typically needs to update the database and send messages/events. For example, a service that participates in a saga needs to atomically update the database and sends messages/events. Similarly, a service that publishes a domain event must atomically update an aggregate and publish an event. The database update and sending of the message must be atomic in order to avoid data inconsistencies and bugs. However, it is not viable to use a distributed transaction that spans the database and the message broker to atomically update the database and publish messages/events.
How to reliably/atomically update the database and publish messages/events?
A service that uses a relational database inserts messages/events into an outbox table (e.g.
MESSAGE) as part of the local transaction.
An service that uses a NoSQL database appends the messages/events to attribute of the record (e.g. document or item) being updated.
A separate Message Relay process publishes the events inserted into database to a message broker.
This pattern has the following benefits:
This pattern has the following drawbacks:
This pattern also has the following issues:
Application architecture patterns
Cross cutting concerns