Datadog/dd-trace-go

[trajanoreuter]

Hi, I'm working on a project and I'm trying to use dd-trace. I didn't find any pre-integration (https://github.com/DataDog/dd-trace-go/tree/main/contrib) so I'm trying to do it from scratch.
unfortunately my project is old and uses iris.v6.
I have this sample code that works almost 100% fine, but the function FinishRequestSpan has one problem.
I commented the problem in InitDatadogMiddleware.
I know the focus would be on the framework itself, but I hope someone has some ideas. Thanks

go version 1.15

package main

import (
	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace"
	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/ext"
	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
	iris "gopkg.in/kataras/iris.v6"
)

func StartRequestSpan(ctx *iris.Context, opts ...ddtrace.StartSpanOption) (tracer.Span, context.Context) {
	opts = append([]ddtrace.StartSpanOption{
		tracer.SpanType(ext.SpanTypeWeb),
		tracer.Tag(ext.HTTPMethod, ctx.Request.Method),
		tracer.Tag(ext.HTTPURL, ctx.Request.RequestURI),
		tracer.Measured(),
	}, opts...)

	if ctx.Host() != "" {
		opts = append([]ddtrace.StartSpanOption{
			tracer.Tag("http.host", ctx.Host()),
		}, opts...)
	}

	if spanctx, err := tracer.Extract(tracer.HTTPHeadersCarrier(ctx.Request.Header)); err == nil {
		opts = append(opts, tracer.ChildOf(spanctx))
	}

	return tracer.StartSpanFromContext(ctx.Request.Context(), "http.request", opts...)
}

func FinishRequestSpan(s tracer.Span, status int, opts ...tracer.FinishOption) {
	var statusStr string

	if status == 0 {
		statusStr = "200"
	} else {
		statusStr = strconv.Itoa(status)
	}

	s.SetTag(ext.HTTPCode, statusStr)

	if status >= 500 && status < 600 {
		s.SetTag(ext.Error, fmt.Errorf("%s: %s", statusStr, http.StatusText(status)))
	}

	s.Finish(opts...)
}

func (s *Server) InitDatadogMiddleware() {
	s.app.UseFunc(func(ctx *iris.Context) {
		spanOpts := []ddtrace.StartSpanOption{
			tracer.ServiceName("dd-iris"),
		}

		resource := ctx.Request.Method + " " + ctx.Path()
		opts := append(spanOpts, tracer.ResourceName(resource))
		opts = append(opts, tracer.Tag(ext.EventSampleRate, 1.0))

		span, _ := datadog.StartRequestSpanIris(ctx, opts...)
		var finishOpts []tracer.FinishOption

                // this don't work, my server return but the request stops here
	        defer FinishRequestSpan(span, ctx.Request.Response.StatusCode, finishOpts...)
	        
                // this works, but I don't have my response code status TAG.
	        defer span.Finish()

		err := tracer.Inject(span.Context(), tracer.HTTPHeadersCarrier(ctx.Request.Header))

		if err != nil {
			log.WithError(err).Error("an error ocurred initializing datadog middleware")
			ctx.Next()
		}

		ctx.Next()
	})
}

[kataras]

Hello @trajanoreuter,

Unfortunately, Iris version 6 is very very old and it's not supported anymore. If you need help to upgrade your app to the latest Iris version (v12.2.0-betaX), please send me a message at https://chat.iris-go.com so we can arrange a call. If you don't have time to upgrade your web app, I can do it for you for absolutely free (and fix the ddtrace integration issue you have too).

[trajanoreuter]

Hi @kataras ,
Unfortunately it's a closed project from my company, but thanks for the availability.
I'll try another approach or go without the response code. It would already meet almost 100% of what we need.
And thanks for the quick response.

[trajanoreuter]

I found my mistake, I was using function ctx.Request.Response.StatusCode, when I should actually be using ctx.StatusCode().