How do you handle versioning in microservices?

Microservice versioning is a key practice for managing changes to service interfaces and behaviors, ensuring that services can evolve independently without breaking dependencies. Its importance lies in supporting continuous delivery, enabling canary releases, and ensuring overall system stability, with wide applications in cloud-native and distributed systems.

The core elements include interface contract management (e.g., using OpenAPI/Swagger), semantic versioning specifications (SemVer), and the ability to run multiple versions in parallel on the backend. It is necessary to strictly distinguish between compatible changes (minor version iterations) and incompatible changes (major version upgrades). In practice, routing control is performed through an API gateway, version discovery is achieved in conjunction with a service registry, and compatibility is verified using contract testing tools (such as Pact).

Processing steps: 1. Clearly define an API versioning strategy (e.g., URL path/request header identification) 2. Deploy new and old versions of services in parallel 3. Control traffic through gateway routing policies (e.g.,分流至v2版 by proportion) 4. Gradually migrate all traffic after monitoring the stability of the new version 5. Deprecate the old version and clean up resources. This solution supports zero-downtime updates, reduces business risks, and is a core enabler of continuous delivery.