fasthttp_zerolog_opentracing.go

package main

import (
	"fmt"
	"io"
	"time"

	"github.com/opentracing/opentracing-go"
	otlog "github.com/opentracing/opentracing-go/log"
	"github.com/rs/zerolog/log"
	jaeger "github.com/uber/jaeger-client-go"
	config "github.com/uber/jaeger-client-go/config"
	"github.com/valyala/fasthttp"
)

var (
	listenAddr = "127.0.0.1:8080"
)

func instrument(service string) (opentracing.Tracer, io.Closer) {
	cfg := &config.Configuration{
		Sampler: &config.SamplerConfig{
			Type:  "const",
			Param: 1,
		},
		Reporter: &config.ReporterConfig{
			LogSpans: true,
		},
	}
	tracer, closer, err := cfg.New(service, config.Logger(jaeger.StdLogger))
	if err != nil {
		panic(fmt.Sprintf("ERROR: cannot init Jaeger: %v\n", err))
	}
	opentracing.SetGlobalTracer(tracer)
	return tracer, closer
}

func requestHandler(ctx *fasthttp.RequestCtx) {
	fmt.Fprintf(ctx, "Hello, world! Requested path is %q", ctx.Path())
}

func loggingMiddleware(req fasthttp.RequestHandler) fasthttp.RequestHandler {
	return fasthttp.RequestHandler(func(ctx *fasthttp.RequestCtx) {
		begin := time.Now()
		req(ctx)
		end := time.Now()
		log.Info().
			Bytes("method", ctx.Method()).
			Str("remoteAddr", ctx.RemoteAddr().String()).
			IPAddr("remoteIP", ctx.RemoteIP()).
			Int("status", ctx.Response.Header.StatusCode()).
			Bytes("uri", ctx.RequestURI()).
			Bytes("userAgent", ctx.UserAgent()).
			Dur("latency", end.Sub(begin)).
			Msg("request")
	})
}

func tracingMiddleware(req fasthttp.RequestHandler) fasthttp.RequestHandler {
	return fasthttp.RequestHandler(func(reqCtx *fasthttp.RequestCtx) {
		span, _ := opentracing.StartSpanFromContext(reqCtx, string(reqCtx.RequestURI()))
		defer span.Finish()
		span.LogFields(
			otlog.String("event", "request"),
			otlog.Int("status", reqCtx.Response.Header.StatusCode()),
		)
	})
}

func main() {
	_, closer := instrument("blah-app")
	defer closer.Close()

	handler := loggingMiddleware(tracingMiddleware(requestHandler))
	if err := fasthttp.ListenAndServe(listenAddr, handler); err != nil {
		log.Fatal().Str("listenAddr", listenAddr).Err(err).Msg("error listening")
	}
}