How to Export Custom Metrics from Go Applications

Export custom metrics by defining a metrics.Sample slice with your metric names and calling metrics.Read to retrieve values. You can then format and send these values to your monitoring system.

import "runtime/metrics"

func getCustomMetrics() {
    sample := []metrics.Sample{
        {Name: "/custom/your_metric:bytes"},
    }
    metrics.Read(sample)
    for _, s := range sample {
        // Process s.Value (e.g., send to Prometheus)
    }
}

Note: Custom metrics must be registered in your code using metrics.Register (if supported in your Go version) or rely on existing runtime metrics like /godebug/non-default-behavior/<name>:events for GODEBUG settings.

Go's runtime metrics system lets you track internal program stats like memory usage or custom counters. You define which stats you want, ask the runtime for them, and then send that data to your monitoring tools. Think of it like checking a car's dashboard gauges to see speed or fuel level before reporting them to a fleet manager.