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Eventuate TRAM - SAGA Sample

• Java 8
• Docker
• Eventuate TRAM
• Maven
• Microservices Architecture
• CQRS
• Event Sourcing
• Saga Pattern
• Jenkins

Sample Description

Order Service

• Receive a ProductInfo object and CustomerId.
• Create an order with state completed like false
• Send a request to Customer Service to check if the customer exists.
• Send a request to Invoice Service to generate an invoice order.
• If all the process is done successfully so it updates the order state to completed like true.

Customer Service

• Receive an orderId and customerId
• Check the Customer and return the result.

Invoice Service

• Receive a request to create an invoice.
• Create an invoice.
• Return an invoice if everything is ok.

Order View Service

• Receive all events generated by the other services
• Update a database
• Expose an API to get information about the services (i.e. Orders, Customers, Invoices)

Note: If something wrong occurrs during the saga execution, the order is rejected to compensate the process.

Saga Definition - CreateOrderSaga

$ public CreateOrderSaga(OrderServiceProxy orderService, CustomerServiceProxy customerService, InvoiceServiceProxy invoiceService) {
		this.sagaDefinition =
				step()
					.withCompensation(orderService.reject, this::makeRejectOrderCommand)
				.step()
					.invokeParticipant(customerService.validateOrder, this::makeValidateOrderByCustomer)						
				.step()
					.invokeParticipant(invoiceService.requestInvoice, this::makeRequestInvoice)
					.onReply(InvoiceInfo.class, this::handleInvoiceReply)
					.withCompensation(invoiceService.cancelInvoice, this::makeCancelRequestInvoice)
				.step()
					.invokeParticipant(orderService.complete, this::makeCompleteOrderCommand)	
				.build();

Building and Running

$ mvn clean package -s settings.xml docker:build

$ docker-compose up --abort-on-container-exit

Swagger UI

Customer Service. (Create at least one customer)

http://localhost:5001/swagger-ui.html

Order Service. (Create an order to execute the saga)

http://localhost:5000/swagger-ui.html

Invoice Service. (Search your order invoices)

http://localhost:5002/swagger-ui.html

Order View Service. (Search everything)

http://localhost:5003/swagger-ui.html