Sagas

Problem

In a distributed system, messages sent by the services might not be controlled. As the system grows and more services are added, the system starts becoming unmaintainable. In a large distributed system, it becomes hard to track which message goes where.

Sagas (Problem)

Another problem that Microservices-based system encounters is that there is no single source of truth that can be used by all the services. For instance, in an e-commerce application, when a customer places an order a message containing order details is sent to the procurement service. Once the order service responds, another message containing delivery details is sent to the delivery service. This leads to there being no single source of truth that contains the entire customer order data.

Solution

Using sagas, workflows can be implemented in a Microservice application. Sagas are state machines that model a workflow with steps to be executed. Sagas treat the various Microservices as implementations of workflow.

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