Camel-InMemorySaga

This Example shows how to configure IN-MEMORY SAGA SERVICE using Apache Camel

Apache Camel Documentation

https://camel.apache.org/components/4.4.x/eips/saga-eip.html#_using_the_in_memory_saga_service

Code Walkthrough

In this example we will create an inventory service, using Spring Boot and Apache Camel DSL. We will create 1 route direct:createInventory with 2 saga routes for compensation and completion

        from("direct:createInventory")
                .process(
                        exchange -> {
                            exchange.getMessage().setHeader("id", UUID.randomUUID().toString());

                        }).saga().to("direct:newInventory");

        from("direct:newInventory").saga()
                .propagation(SagaPropagation.MANDATORY)
                .option("id", header("id"))
                .compensation("direct:cancelInventory")
                .completion("direct:completeInventory")
                .bean(createInventoryService, "createInventory");

        from("direct:completeInventory").bean(createInventoryService, "completeInventory");

        from("direct:cancelInventory").bean(cancelInventoryService, "cancelInventory");

When creating a new Inventory, bean createInventoryService is called (you can refer to CreateInventoryService.java)

Following actions are undertaken by SAGA:

1. Positive Case: If new inventory is created, after execution of direct:newInventory "completion" route is called ie direct:completeInventory
2. Negative Case: If error is thrown while creating Inventory, "compensation" route is called ie direct:cancelInventory

How to Run this Application

This is a simple maven application, just clone the repo and open cmd and run:

To Compile:

mvn clean install

To run the spring application

mvn clean compile exec:java

How to Test the Application

Open postman and hit this GET endpoint:

localhost:8006/createInventory

Note: By Default application run on 8006 port. Which can be changed under application.yml file

server:
  port: 8006