This is an example of a little application that manage different sensor stations using multiple services that interacts with AMQP and expose a REST API interface.

There are two type of services:

This service represents a service that manage a set of sensors mounted in a room. The service read data from sensors send it to another service ("SensorManager") through RabbitMQ. Sensor are mocked internally at the service with random generators) Every station have 2 sensors: (Oxygen, Humidity) In this example we is used the topic exchange type of RabbitMQ where the routing-key is composed by sensor.station-name (e.g. oxygen.station1)

This service have two purpose:

• Collect data from the registered "SensorStation"s through RabbitMQ
• The service keeps in memory only 10 last values of each sensors (you can choose what data structure use e.g list, queue, set ecc..)
• Offers a REST interface that can be used by a generic User Application:
  • Add a new station, when this api is used the station manager add a listener to the value sent from the new station.
    The name of the station will be sent in the body of the message
    • POST: http://{hostname}:{port}/addstation
  • Get all station info (name + current sensors values)
    • GET: http://{hostname}:{port}/stations/
  • Get info of a specific station
    • GET: http://{hostname}:{port}/stations/station_name
  • Get the sensor values of a station
    • GET: http://{hostname}:{port}/stations/station_name/sensor_name/

In the file "UserInteractionSimulator.kt" there is a function that simulate a generic User App that interact with the REST interface of the "SensorManager".

This is one of the code examples created for the course in "Distributed Systems".

authors: Matteo Gabellini & Elia Di Pasquale