This repository contains a system simulating an Orb for the purposes of development and/or testing. It is written in Java and uses the Spring Boot framework. The gradle build tool is used for dependency management, compilation, and packaging.
The design rationale is articulated in this document.
The system includes two primary components, the SignupSimulator and the StatusReporter, and several other supporting components.
This component repeatedly generates a random image and UUID, uploads the former to an object storage backend, and then sends an HTTP POST request to a backend API with the image URL and the aforementioned ID.
This component generates fake values for the following set of four metrics:
- battery
- cpu temperature
- cpu utilization
- disk utilization
These metrics are submitted to Micrometer.
This component is an embedded REST API consisting of the POST /signup endpoint, for testing the SignupSimulator. It can be disabled in production.
This component provides access to an object storage backend for the SignupSimulator to upload images to. By default, it uses an in-memory S3-compatible server (mock-backend) and stores the uploaded objects on disk. In production, it can be configured to work with S3 or any S3-compatible system.
This component is the built-in Spring instrumentation & management framework; it is used to configure and host the metrics system, Micrometer. Both the Prometheus and Statsd registries are supported, but only the former is enabled by default.
With the bundled configuration, the metrics can be accessed at this URL.
On a POSIX-compatible system, use the included gradelw wrapper script to build, package, and run.
To build and execute the application:
./gradlew bootRunTo produce a Docker image, first ensure the daemon is running, and then:
./gradlew jibDockerBuildTo run the Docker container, you must either disable the mock-backend, or mount a directory for it to use to persist uploaded images, and provide its path to the application.
sudo docker run -v moculus-bucket:/opt/moculus/moculus-bucket:rw edobry/moculus -e MOCK_BACKEND_PATH=/opt/moculus/moculus-bucketAs we are using Spring, we can take advantage of the built-in configuration modalities, namely the application.yaml config file, as well as the automatic environment variable merge; that is, any known field in the file can also be set through an appropriately-named envvar.
For example, the field mock-backend.path can be set using the MOCK_BACKEND_PATH environment variable.
This repository includes two JUnit test classes containing a rudimentary set of tests, convering the basic logic of the provided requirements.
Hire @edobry :)