Tell about monitoring and metrics in the project (Prometheus, Grafana)

Monitoring and metrics play a key role in tracking the system's state and quickly responding to issues in a project. Prometheus is a monitoring system and metrics collector with the ability to store time series data. It collects metrics from applications and infrastructure via HTTP endpoints, using a pull model.

Grafana is a visualization tool that connects to Prometheus and other data sources, allowing the creation of dashboards for convenient metric analysis.

In Kotlin projects, libraries like Micrometer are often used, which integrate with Prometheus and make it easy to export metrics from the application.

Example of exporting metrics in Kotlin with Micrometer and Prometheus:

import io.micrometer.core.instrument.MeterRegistry

class BookService(private val meterRegistry: MeterRegistry) {
    private val booksCounter = meterRegistry.counter("books_processed_total")

    fun processBook(bookId: String) {
        // book processing logic
        booksCounter.increment()
    }
}

Thus, metrics are collected and available for Prometheus, and dashboards for monitoring performance, errors, load, and other important parameters can be configured in Grafana.