What microservice development patterns do you know?

In microservice architecture, various patterns are used to organize interactions between services, ensure fault tolerance, and scalability. Here are some key patterns:

• API Gateway — a single entry point for all clients that routes requests to the appropriate microservices.
• Service Discovery — a mechanism for dynamically discovering service addresses so that microservices can find each other without hard-coded IPs.
• Circuit Breaker — a pattern to prevent cascading failures by disabling calls to non-responsive services.
• Saga — a pattern for managing distributed transactions through a sequence of local transactions with compensating actions.
• Event Sourcing — storing system state as a sequence of events, which simplifies recovery and auditing.
• CQRS (Command Query Responsibility Segregation) — separating read and write operations to optimize performance and scalability.

An example of implementing a Circuit Breaker in C++ can be done through a wrapper around service calls with a timeout and error counter, which blocks further calls when a threshold is exceeded.