Meter readings

Meter readings is a REST Service for fetching and storing energy consumption for specific meter by year and month. For simple use and testing purposes we are using H2 in-memory database. Service is started on port 8080.

Test, build and run

Maven automation tool is used for testing the service and building JAR. Testing and building is started with next command inside the project ./mvnw clean test package.

All test should pass and JAR is generated in ./target directory which should appear inside project upon completion of the last command. JAR can be started with command java -jar ./target/meter-readings-0.0.1-SNAPSHOT.jar. You should be able to access the REST service endpoints through browser or Postman. Service starts on localhost and port 8080, testing URLs are:

• http://localhost:8080/api/v1/meters/1/consumption/aggregation/2020
  • Produces JSON

    {
      "year": 2020,
      "total": 195
    }
    

• http://localhost:8080/api/v1/meters/1/2020
  • Produces JSON

    {
      "year": 2020,
      "monthlyEnergyConsumption": {
        "June": 18,
        "October": 25,
        "December": 22,
        "May": 16,
        "September": 8,
        "March": 9,
        "July": 12,
        "January": 11,
        "February": 14,
        "April": 23,
        "August": 17,
        "November": 20
      }
    }
    

• http://localhost:8080/api/v1/meters/1/2020/1
  • Produces JSON

    {
      "year": 2020,
      "monthlyEnergyConsumption": {
        "January": 18
      }
    }
    

Endpoint for saving meter reading is /api/v1/meters/reading and it expects JSON object, the same object is returned.

{
    "year": 2021,
    "month": 1,
    "energyConsumed": 15,
    "meterId": 1
}

Docker

Application can be started as Docker container. Dockerfile holds specification for creating the image. To be able to create docker image, previously command ./mvnw clean test package has to be run inside the project.

Running commands creates image and starts the container at port 8080:

• docker build -t meter-readings -f Dockerfile . - creates docker image with tag meter-readings
• docker run --name meter-readings -p 8080:8080 meter-readings - runs docker container with name meter-readings on port 8080.

OpenAPI

OpenAPI with swagger UI is available after starting the service.
Links to docs are http://localhost:8080/swagger-ui/index.html or http://localhost:8080/swagger-ui-meterreadings.html.

TODO

• Parametrize integration tests
• Parametrize unit tests
• Create proper mapper for before/after save/update meter reading