About Microservices.io

Microservices.io is brought to you by Chris Richardson. Experienced software architect, author of POJOs in Action and the creator of the original CloudFoundry.com. His latest startup is eventuate.io, a microservices application platform.

Microservices consulting and training

Chris offers a comprehensive consulting services, workshops and hands on training classes to help you use microservices effectively.

Avoid the pitfalls of adopting microservices and learn essential topics, such as service decomposition and design and Kubernetes. Find out more

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Chris offers a comprehensive set of resources for learning about microservices including articles, an O'Reilly training video, and example code.

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Example microservices applications

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A pattern language for microservices

The beginnings of a pattern language for microservice architectures.


Click here for Chinese translation of the patterns

Click here for PDF

Application architecture patterns

Which architecture should you choose for an application?


How to decompose an application into services?

Deployment patterns

How to deploy an application’s services?

Cross cutting concerns

How to handle cross cutting concerns?

Communication patterns


Which communication mechanisms do services use to communicate with each other and their external clients?

External API

How do external clients communicate with the services?

Service discovery

How does the client of an RPI-based service discover the network location of a service instance?


How to prevent a network or service failure from cascading to other services?

  • Circuit Breaker - invoke a remote service via a proxy that fails immediately when the failure rate of the remote call exceeds a threshold

Transactional messaging

How to publish messages as part of a database transaction?

Data management

How to maintain data consistency and implement queries?

  • Database per Service - each service has its own private database
  • Shared database - services share a database
  • Saganew - use sagas, which a sequences of local transactions, to maintain data consistency across services
  • API Compositionnew - implement queries by invoking the services that own the data and performing an in-memory join
  • CQRS - implement queries by maintaining one or more materialized views that can be efficiently queried
  • Event sourcing - persist aggregates as a sequence of events


How to communicate the identity of the requestor to the services that handle the request?

  • Access Token - a token that securely stores information about user that is exchanged between services


How to make testing easier?

  • Consumer-driven contract test - a test suite for a service that is written by the developers of another service that consumes it
  • Consumer-side contract test - a test suite for a service client (e.g. another service) that verifies that it can communicate with the service
  • Service component sest - a test suite that tests a service in isolation using test doubles for any services that it invokes


How to understand the behavior of an application and troubleshoot problems?

  • Log aggregation - aggregate application logs
  • Application metrics - instrument a service’s code to gather statistics about operations
  • Audit logging - record user activity in a database
  • Distributed tracing - instrument services with code that assigns each external request an unique identifier that is passed between services. Record information (e.g. start time, end time) about the work (e.g. service requests) performed when handling the external request in a centralized service

  • Exception tracking - report all exceptions to a centralized exception tracking service that aggregates and tracks exceptions and notifies developers.

  • Health check API - service API (e.g. HTTP endpoint) that returns the health of the service and can be pinged, for example, by a monitoring service

  • Log deployments and changesnew

UI patterns

How to implement a UI screen or page that displays data from multiple services?

  • Server-side page fragment composition - build a webpage on the server by composing HTML fragments generated by multiple, business capability/subdomain-specific web applications

  • Client-side UI composition - Build a UI on the client by composing UI fragments rendered by multiple, business capability/subdomain-specific UI components

Copyright © 2018 Chris Richardson • All rights reserved • Supported by Kong.