middleware.go

// Copyright © 2023 Ory Corp
// SPDX-License-Identifier: Apache-2.0

package otelx

import (
	"net/http"
	"strings"

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

func isHealthFilter(r *http.Request) bool {
	path := r.URL.Path
	return !strings.HasPrefix(path, "/health/")
}

func isAdminHealthFilter(r *http.Request) bool {
	path := r.URL.Path
	return !strings.HasPrefix(path, "/admin/health/")
}

func filterOpts() []otelhttp.Option {
	filters := []otelhttp.Filter{
		isHealthFilter,
		isAdminHealthFilter,
	}
	opts := []otelhttp.Option{}
	for _, f := range filters {
		opts = append(opts, otelhttp.WithFilter(f))
	}
	return opts
}

// NewHandler returns a wrapped otelhttp.NewHandler with our request filters.
func NewHandler(handler http.Handler, operation string, opts ...otelhttp.Option) http.Handler {
	opts = append(filterOpts(), opts...)
	return otelhttp.NewHandler(handler, operation, opts...)
}

// TraceHandler wraps otelx.NewHandler, passing the URL path as the span name.
func TraceHandler(h http.Handler, opts ...otelhttp.Option) http.Handler {
	// Use a span formatter to set the span name to the URL path, rather than passing in the operation to NewHandler.
	// This allows us to use the same handler for multiple routes.
	middlewareOpts := []otelhttp.Option{
		otelhttp.WithSpanNameFormatter(func(operation string, r *http.Request) string {
			return r.URL.Path
		}),
	}
	return NewHandler(h, "", append(middlewareOpts, opts...)...)
}