Service Monitor Application

A modular monitoring application monitoring services, e.g., Jenkins, Sonar, … with different notifiers. One of which can be our Status Light with Raspberry Pi Zero and W2812 Led Strip we did last time.

The idea of building a monitor application came from a colleague, who was using a similar application connected to a Blink1 light. The one LED USB dongle seem too expensive to me so I thought I will build something bigger 🙂

The core of the application is made up from Data, API, Control and UI modules. The Data module simply contains the different POJOs, e.g., Config, Status, Priority. The API module contains interface logic, e.g., Module, ServiceModule, NotifierModule. The Control module puts the things together and the UI module contains some UI specific stuff for modules which want to use UI.

Then we have a bunch of modules: Jenkins, Sonar, Raspi W2812 and System Tray. The former two are Service modules and the later are Notifier modules. Service modules check a status of a certain service and lets the Controller know through the API module. While Notifier modules are notified by the Controller over the API about Status changes and react to them.

What the two concrete services do is pretty much self-explanatory. The Jenkins module checks the status of one or more Jenkins jobs and the Sonar module check the status of one or more sonar projects. Also each module can be instantiated multiple times so multiple Jenkins or Sonar installations may be included.

The System Tray Notifier displays the status in the system tray. It also uses the UI module which enables to access the configuration window through the system tray.

The Raspi W2812 module connects to our light, we developed last time, via USB and changes the light pattern, color, etc.

Everything revolves around a StatusItem in the Data module. Service modules have to translate the state of their services to it and send a list of such entities to the Controller who stores them in a list (one StatusItem per Item). An Item is, e.g., a Jenkins Job or a Sonar Project. The Priority is taken from the configuration where you can set a default Priority for a whole Service and per each Service item.

Every time the collection of StatusItems changes the Notifier modules get notified. Depending on their capability they can display them. So for example the System Tray module can display only one StatusItem so it chooses the one with the worst Status. Our Raspi W2812 module chooses a collection of StatusItems with the worst Status and highest Priority. Then it rotates the corresponding light patterns and colors.

The last Assembly module just takes the modules and build a Fat Jar with a main method so we can start it. The Assembly module and the concept is done in a way so we can replace the Assembly with, e.g., Web module and start the whole thing as a web service.

You can check out the code here: If you build your light from the previous post its pretty cool


The Blink1 LED USB dongle could also be supported by this application, you would just need to program another Notifier module.


19.12.2018: updated backend for raspberry:

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