Same SpanID, ParentID and TraceID in every span in different services

Hi,

I just dived into Zipkin and it’s really cool so far. But I couldn’t get it running perfectly. To test the interaction I set up two express Server in docker and one is calling the other.

However, both servers emit the same Span information SpanID, ParentID and TraceID. Is that an intended behaviour, a bug or did I screw something up?

Is the Service that creates the root span (in this case watch_1) supposed to have a ParentID?

(watch_1 calls, fetchme_1 responds )

If the environment variable FETCH_URL is set it will act as the caller otherwise it will just respond to queries.

import * as express from "express";

var fetch = require('node-fetch');
const {trace, BatchRecorder, Tracer, ExplicitContext, ConsoleRecorder} = require('zipkin');
const zipkinMiddleware = require('zipkin-instrumentation-express').expressMiddleware;
const {HttpLogger} = require('zipkin-transport-http');
const CLSContext = require('zipkin-context-cls');

var ctxImpl = new ExplicitContext();
var recorder = new ConsoleRecorder();

const tracer = new Tracer({
    recorder: recorder,
    ctxImpl: new CLSContext('zipkin')
});


//CALLER
const wrapFetch = require('zipkin-instrumentation-fetch');

const zipkinFetch = wrapFetch(fetch, {
    tracer,
    serviceName: process.env.SERVICE_NAME + '-fetch-' + process.env.APPLICATION_PORT,
    port: process.env.APPLICATION_PORT
});

if (process.env.FETCH_URL != undefined) {
    setTimeout(function () {
        zipkinFetch(process.env.FETCH_URL).then(function (res) {
            return res.text();
        }).then(function (body) {
            console.log(body)
        });
    }, 1000)
}

var app = express();


//RECEIVER
app.use(function (request:express.Request, response:express.Response, next) {
    console.log(request.headers);

    next()
});

app.use(zipkinMiddleware({
    tracer,
    serviceName: process.env.SERVICE_NAME + '-middleware-' + process.env.APPLICATION_PORT,
    port: process.env.APPLICATION_PORT
}));

app.use('/', function (request:express.Request, response:express.Response, next) {
    response.send('Hi');
});





app.listen(process.env.APPLICATION_PORT, function () {
    console.log('The PetStore sample is now running at http://localhost:' + process.env.APPLICATION_PORT);
});

Thanks in advance 😃

[eirslett]

That’s correct behavior. When you have only one span, all the ids in the trace will be the same. There are two services/nodes (I’ll call them nodes, since not all points in the graph have to be services) here, but only one span, because a span represents the interaction between two nodes. If you introduce a third node, for example a web browser, which calls the first service, then there will be two spans in the trace.

[eirslett]

Usually, you would see a setup like this:

browser -> front-facing webapp -> microservice 1 -> microservice 2 -> database

Then, the root span would be “front-facing webapp” in the Zipkin UI. So even if the trace is triggered by the browser, the span starts at the first service.