Orchestration and Chorography in Microservices

 Both Orchestration and Choreography are used for Inter Service Communication (ISC) in microservices.

 Example use case - When an order is completed, an invoice should be generated for the order items.

Orchestration:

• One central service controls entire business transactions
• Its ideal for synchronous Inter Service Communication
• Tightly coupled - All the integration logic exists in a single Orchestration service (Often called as God object)
  
• Easier to Rollback business transaction

 

Solution: OrderOrchestration service  to invoke OrderService.CompleteOrder() first, followed by Invoiceservice.GenerateInvoice(). Here entire integration logic present at the OrderOrchestrationService.

 

Choreography 

• Suited for asynchronous Inter Service Communication
• Loosely coupled
• This is implemented using event based architecture (Example: Apache Kafka/Azure Event Hub). Microservices can be configured as both publisher and subscriber of events.
• Harder to Rollback business transactions

 

Solution - Order Microservice can publish an OrderCompleted event to Event Hub. An Invoice Microservice can be subscribed to this event and can generate invoice based on the subscribed events.