Have you had experience integrating and displaying custom metrics in Grafana?

Yes, experience in integrating and displaying custom metrics in Grafana typically involves the following steps:

1. Collecting metrics: writing code in Go that gathers the necessary data (e.g., performance indicators, business metrics).
2. Exporting metrics: using libraries such as the Prometheus client for Go (prometheus/client_golang) to define and register custom metrics.
3. Exposing metrics: running an HTTP server that serves metrics in a format understandable by Prometheus.
4. Configuring Prometheus to scrape these metrics from your application.
5. Creating dashboards in Grafana based on the collected metrics.

Example of a simple custom metric export in Go:

package main

import (
    "net/http"
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
)

var (
    myCounter = prometheus.NewCounter(
        prometheus.CounterOpts{
            Name: "my_custom_metric_total",
            Help: "Example of a custom metric",
        },
    )
)

func main() {
    prometheus.MustRegister(myCounter)

    http.Handle("/metrics", promhttp.Handler())

    // Increment the counter
    myCounter.Inc()

    http.ListenAndServe(":2112", nil)
}

After running, the application will serve metrics at http://localhost:2112/metrics, which can be collected by Prometheus and visualized in Grafana.