tracing

README

xk6-distributed-tracing

⚠️ This is a proof of concept ⚠️
It won't be supported by the k6 team.
It may also break in the future as xk6 evolves.

This extension adds distributed tracing support to k6! That means, that if you're testing a system that is instrumented, you can use this extension to start the traces on k6.

It is implemented using the xk6 extension system.

Trace started on k6

Features

The extension is built on top of OpenTelemetry, and gives k6:

• An instrumented HTTP client.
• The hability to:
  • Export spans (your tracing data).
    • Supported exporters: jaeger, zipkin, otlp, noop, stdout
  • Propagate context.
    • Supported protocols: w3c, b3, jaeger, ot

Build

To build a k6 binary with this extension, first ensure you have the prerequisites:

• Go toolchain
• Git

Then:

1. Download xk6:

$ go install go.k6.io/xk6/cmd/xk6@latest

1. Build the binary:

$ xk6 build --with github.com/k6io/xk6-distributed-tracing@latest

Example

import tracing, { Http } from 'k6/x/tracing';
import { sleep } from 'k6';

export let options = {
  vus: 1,
  duration: '10s',
};

export function setup() {
  console.log(`Running xk6-distributed-tracing v${tracing.version}`, tracing);
}

export default function() {
  const http = new Http({
    exporter: "jaeger",
    propagator: "w3c",
    endpoint: "http://localhost:14268/api/traces"
  });
  const r = http.get('https://test-api.k6.io');
  console.log(`trace_id=${r.trace_id}`);
  sleep(1);
}

export function teardown(){
  // Cleanly shutdown and flush telemetry when k6 exits.
  tracing.shutdown();
}

Result output:

$ ./k6 run script.js

          /\      |‾‾| /‾‾/   /‾‾/   
     /\  /  \     |  |/  /   /  /    
    /  \/    \    |     (   /   ‾‾\  
   /          \   |  |\  \ |  (‾)  | 
  / __________ \  |__| \__\ \_____/ .io

  execution: local
     script: script.js
     output: -

  scenarios: (100.00%) 1 scenario, 1 max VUs, 40s max duration (incl. graceful stop):
           * default: 1 looping VUs for 10s (gracefulStop: 30s)

INFO[0000] Running xk6-distributed-tracing v0.0.2  source=console                
INFO[0000] trace-id=743fff0b96778539acb7139e72ea1e33
INFO[0001] trace-id=365f4637a52526db1de2d30a5568ca3a
INFO[0002] trace-id=c49e1df945049c5c3c8b59acc84d7d3b
INFO[0003] trace-id=53e1937d56aa172b46d2310e3380dfe9
INFO[0004] trace-id=d61e8757d35c9ca1780b88977ac56d72
INFO[0005] trace-id=358e794ed636d268a918dcd2f3f9db0a
INFO[0006] trace-id=992a959e09ee84f3905a215bec8b53a0
INFO[0007] trace-id=aee11c64de11744ab5b66d5dd8ed361b
INFO[0008] trace-id=c4dc45d857e99ede2bb902666457239d
INFO[0009] trace-id=7623d10293d9f03c15deb8055935664e

running (10.1s), 0/1 VUs, 10 complete and 0 interrupted iterations
default ✓ [======================================] 1 VUs  10s

     █ setup

     data_received..............: 1.6 kB 156 B/s
     data_sent..................: 1.7 kB 165 B/s
     http_req_blocked...........: avg=223.43µs min=146.53µs med=217.39µs max=314.54µs p(90)=276.68µs p(95)=295.61µs
     http_req_connecting........: avg=137.18µs min=87.22µs  med=130.17µs max=196.38µs p(90)=184.38µs p(95)=190.38µs
     http_req_duration..........: avg=6.58ms   min=5.07ms   med=6.45ms   max=7.91ms   p(90)=7.83ms   p(95)=7.87ms  
     http_req_receiving.........: avg=187.27µs min=94.29µs  med=171.7µs  max=295.67µs p(90)=293.28µs p(95)=294.48µs
     http_req_sending...........: avg=128.07µs min=94.64µs  med=121.77µs max=175.65µs p(90)=160.41µs p(95)=168.03µs
     http_req_tls_handshaking...: avg=0s       min=0s       med=0s       max=0s       p(90)=0s       p(95)=0s      
     http_req_waiting...........: avg=6.27ms   min=4.83ms   med=6.13ms   max=7.64ms   p(90)=7.56ms   p(95)=7.6ms   
     http_reqs..................: 10     0.991797/s
     iteration_duration.........: avg=916.48ms min=65.67µs  med=1s       max=1s       p(90)=1s       p(95)=1s      
     iterations.................: 10     0.991797/s
     vus........................: 1      min=1 max=1
     vus_max....................: 1      min=1 max=1

Documentation

Index

• type DistributedTracing
  • func (c *DistributedTracing) Exports() modules.Exports
• type Options
• type RootModule
  • func New() *RootModule
  • func (*RootModule) NewModuleInstance(vu modules.VU) modules.Instance

Types

type DistributedTracing

type DistributedTracing struct {
	// contains filtered or unexported fields
}

func (*DistributedTracing) Exports

func (c *DistributedTracing) Exports() modules.Exports

Exports implements the modules.Instance interface and returns the exports of the JS module.

type Options

type Options struct {
	Exporter   string
	Propagator string
	Endpoint   string
}

type RootModule

type RootModule struct{}

RootModule is the global module instance that will create DistributedTracing instances for each VU.

func New

func New() *RootModule

New returns a pointer to a new RootModule instance.

func (*RootModule) NewModuleInstance

func (*RootModule) NewModuleInstance(vu modules.VU) modules.Instance

NewModuleInstance implements the modules.Module interface and returns a new instance for each VU.