Microservices

Microservice Manifesto

• A microservice must be able to be upgraded without the clients having a matching upgrade
• A microservice should have a clear and public interface / contract
• A microservice's public interface should only have additive changes
• A microservice's can add new properties to DTOs but they must not be required
• A microservice must support older version of interface
• A microservice can create new endpoints
• A microservice should be autonomous

About

• Autonomous
• Single responsibility principle
  • Do one thing and do it well
• Should be able to deploy on it's own
• Perform well
• Resilience to error
• Secure

• Own their own data
• Independently deployable
• Within specific boundaries

When do you need one

• When scaling

How to

Avoid upgrade issues

• Split up team ownership of microservices
  • First add new features
  • Then deploy updated microservice
  • Later update clients
• Automated tests
  • Ensure that older clients are supported
  • Run as part of CI build process
• Beware of shared code
  • Can result in tight coupling