Application Monitoring with Prometheus
When it comes to monitoring, keeping track of our CPU, memory, and other infrastructure metrics often isn't enough. Beyond the common infrastructure-based metrics we expose via tools such as the Node Exporter, we also want to instrument our application to send out metrics related to the app itself. This is done by using the Prometheus client library available to our application's language.
Once we have the client library set up in our application, we can then define any metrics we wish to collect and write the code to support them. We can also have the Prometheus client record a number of default metrics already included in the library and available to us. Once finished, we'll have added metrics for our to-do application that track added and removed tasks, as well as response times across our app.