Echo Reactive REST API

This is a simple message echoing REST service, includes the following points:

1. Demotrate the basic usage of Spring WebFlux.
2. Show case the usage of service and log tracing by utilizing Spring Cloud Sleuth.
3. Experiment on logging the full inbound and outbound HTTP request & response, including HTTP start/status line, headers, and full body.

HOW-TOs

1. To launch the application as a standalone service (at http://localhost:8080), use the sole profile, for example:

   java -jar echo-rx-rest-api-1.0.0-SNAPSHOT.jar --spring.profiles.active=sole
   

   OR

   mvn spring-boot:run -Dspring-boot.run.profiles=sole
   

2. To launch the application instances to form a simplified/minified microservices example, use the main and sub profile, for example:

• For the main service (at http://localhost:8080):

  java -jar echo-rx-rest-api-1.0.0-SNAPSHOT.jar --spring.profiles.active=main
  

  OR

  mvn spring-boot:run -Dspring-boot.run.profiles=main
  

• For the sub service (at http://localhost:8081):

  java -jar echo-rx-rest-api-1.0.0-SNAPSHOT.jar --spring.profiles.active=sub
  

  OR

  mvn spring-boot:run -Dspring-boot.run.profiles=sub
  

The Echo Service

1. In the standalone mode, the service echoes the input message with message SOLE::input;
2. In the sub-service mode, the service echoes the input message with message SUB::input;
3. In the main-service mode (assuming the sub-service is working), the service echoes the input message with message MAIN::SUB::input.