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Monitor Go net/http performance with OpenTelemetry

Package net/http provides HTTP client and server implementations. It allows you to make and serve HTTP requests in Golang.

This article will teach you how to monitor net/http performance using OpenTelemetry observability framework.

What is OpenTelemetry?

OpenTelemetryopen in new window is an open-source observability framework for distributed tracingopen in new window (including logs and errors) and OpenTelemetry metricsopen in new window.

Otel allows developers to collect and export telemetry data in a vendor agnostic way. With OpenTelemetry, you can instrument your application once and then add or change vendors without changing the instrumentation, for example, here is a list popular DataDog alternativesopen in new window that support OpenTelemetry.

OpenTelemetry is available for most programming languages and provides interoperability across different languages and environments.

net/http instrumentation

To install net/http OpenTelemetry instrumentation:

go get go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp

Instrumenting http.Server

You can instrument HTTP server by wrapping all your handlers:

handler := http.Handler(http.DefaultServeMux) // or use your router
handler = otelhttp.NewHandler(handler, "")

httpServer := &http.Server{
    Addr:         ":8888",
	ReadTimeout:  5 * time.Second,
	WriteTimeout: 10 * time.Second,
	IdleTimeout:  60 * time.Second,
	Handler:      handler,
}

err := httpServer.ListenAndServe()

Filtering requests

You can exclude some requests from being traced using otelhttp.WithFilteropen in new window:

handler = otelhttp.NewHandler(handler, "", otelhttp.WithFilter(otelReqFilter))

func otelReqFilter(req *http.Request) bool {
	return req.URL.Path != "/ping"
}

Span name

You can customize span name formatting using otelhttp.WithSpanNameFormatteropen in new window:

handler = otelhttp.NewHandler(handler, "", otelhttp.WithSpanNameFormatter(httpSpanName))

func spanName(operation string, req *http.Request) string {
	return operation
}

Route attribute

If you are instrumenting individual handlers (not all handlers at once), you can annotate handler spans with http.route attribute. This can be useful when you can't find an instrumentation for your router.

handler = otelhttp.WithRouteTag("/hello/:username", handler)

Instrumenting http.Client

otelhttp provides a HTTP transport to instrument http.Client:

client := http.Client{
	Transport: otelhttp.NewTransport(http.DefaultTransport),
}

You can also use the following shortcuts to make HTTP requets:

import "go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"

resp, err := otelhttp.Get(ctx, "https://google.com/")

What is Uptrace?

Uptrace is an open source APMopen in new window for OpenTelemetry with an intuitive query builder, rich dashboards, automatic alerts, and integrations for most languages and frameworks.

You can get startedopen in new window with Uptrace by downloading a DEB/RPM package or a pre-compiled Go binary.

What's next?

Next, instrumentopen in new window more operations, for example, database queries, errors, and logs. You can also learn about OpenTelemetry Go Tracing APIopen in new window to create your own instrumentations.

Popular instrumentations:

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