Validating Oauth credentials in K6 load test script

Question

I am trying to grab a token and pass it into the GET requests.

The below works, but it's grabbing a token every single time a request runs. Ideally I want to grab it once per run and pass it to the requests.

Any ideas on how to make that happen from the below code?

import http from "k6/http";
import { sleep } from "k6";
import { check } from "k6";
import { htmlReport } from "https://raw.githubusercontent.com/benc-uk/k6-reporter/main/dist/bundle.js";

export let options = {
  insecureSkipTLSVerify: true,
  noConnectionReuse: false,
  vus: 5,
  duration: "10s",
};

  
var client_id = "clientId123";
var secret = "secret123";
var scope = "scope123";


export default () => {

  var body =
  "grant_type=client_credentials&client_id=" +
  client_id +
  "&client_secret=" +
  secret +
  "&scope=" +
  scope;

  var tokenResponse = http.post( "https://login.microsoftonline.com/tenantID123/oauth2/v2.0/token", body, { headers: { ContentType: "application/x-www-form-urlencoded"}});
  var result = JSON.parse(tokenResponse.body);
  var token = result.access_token;

   check(tokenResponse, {
    'is status 200': (r) => r.status === 200
   })

  var resp1 = http.get("url_1", {
    headers: { Authorization: `Bearer ${token}` },
  });
  var resp2 = http.get("url_2", {
    headers: { Authorization: `Bearer ${token}` },
  });

  check(resp1, {
      'is status 200': (r) => r.status === 200,
    })
    check(resp2, {
      'is status 200': (r) => r.status === 200,
    })

};

Answer 1

In k6 lifecycle there are 4 stages. You need to use the proper one for your need.

Get exactly one token for the whole test

Can use setup function

export function setup(){
  var client_id = "clientId123";
  var secret = "secret123";
  var scope = "scope123";

  var body =
    "grant_type=client_credentials&client_id=" +
    client_id +
    "&client_secret=" +
    secret +
    "&scope=" +
    scope;

  var tokenResponse = http.post(
    "https://login.microsoftonline.com/tenantID123/oauth2/v2.0/token",
    body,
    { headers: { ContentType: "application/x-www-form-urlencoded" } }
  );
  var result = JSON.parse(tokenResponse.body);
  var token = result.access_token;

  return {token}
}

export default (data) => {
    var token = data.token;
    // Rest ...

}

Get one token for every VU (Virtual User)

Can use "init code."

// ...
var body =
"grant_type=client_credentials&client_id=" +
client_id +
"&client_secret=" +
secret +
"&scope=" +
scope;

var tokenResponse = http.post(
"https://login.microsoftonline.com/tenantID123/oauth2/v2.0/token",
body,
{ headers: { ContentType: "application/x-www-form-urlencoded" } }
);
var result = JSON.parse(tokenResponse.body);
var token = result.access_token;

export default () => {
  var resp1 = http.get("url_1", {
    headers: { Authorization: `Bearer ${token}` },
  });
  // ...
};