What do you know about the Saga pattern? When to apply orchestration and when choreography?

The Saga pattern is used for managing distributed transactions in a microservices architecture, where traditional ACID transactions are not possible. Saga breaks a large transaction into a series of local transactions, each with a compensating action in case of rollback.

Orchestration — centralized management: a dedicated orchestrator service controls the sequence of steps by calling microservices and handling errors. Suitable when strict control and complex logic are important.

Choreography — decentralized management: each service publishes events about its actions, and other services react to them, performing their steps. Suitable for simple scenarios and when reducing coupling between services is desired.

The choice between them depends on the complexity of business logic, control requirements, and scalability. Orchestration is more convenient for complex processes, while choreography is better for simpler and more flexible ones.