05.custom-metrics.js

import { browser } from "k6/browser";
import { check } from "k6";
import { Trend } from "k6/metrics";

const BASE_URL = __ENV.BASE_URL || "http://localhost:3333";

export const options = {
  scenarios: {
    pizzaRecommendations: {
      executor: "shared-iterations",
      options: {
        browser: {
          type: "chromium",
        },
      },
      exec: "pizzaRecommendations",
    },
    admin: {
      executor: "shared-iterations",
      options: {
        browser: {
          type: "chromium",
        },
      },
      exec: "admin",
    },
  },
  thresholds: {
    browser_web_vital_fcp: ["p(95) < 1000"],
    browser_web_vital_lcp: ["p(95) < 2000"],
  },
};

const myTrend = new Trend("totalActionTime");

export async function admin() {
  let checkData;
  const page = await browser.newPage();

  try {
    await page.goto(`${BASE_URL}/admin`);
    await page.locator('button[type="submit"]').click();
    checkData = await page.locator('//*[text()="Logout"]').textContent();
    check(page, {
      "logout button text": checkData == "Logout",
    });
  } finally {
    await page.close();
  }
}

export async function pizzaRecommendations() {
  let checkData;
  const page = await browser.newPage();
  try {
    await page.goto(BASE_URL);
    await page.evaluate(() => window.performance.mark('page-visit'));
    checkData = await page.locator("h1").textContent();
    check(page, {
      header: checkData == "Looking to break out of your pizza routine?",
    });

    await page.locator('//button[. = "Pizza, Please!"]').click();
    await page.waitForTimeout(500);
    await page.screenshot({ path: "screenshot.png" });

    page.evaluate(() => window.performance.mark("recommendations-returned"));
    checkData = await page.locator("div#recommendations").textContent();
    check(page, {
      recommendation: checkData != "",
    });
    //Get time difference between visiting the page and pizza recommendations returned
    await page.evaluate(() =>
      window.performance.measure(
        "total-action-time",
        "page-visit",
        "recommendations-returned"
      )
    );

    const totalActionTime = await page.evaluate(
      () =>
        JSON.parse(
          JSON.stringify(
            window.performance.getEntriesByName("total-action-time")
          )
        )[0].duration
    );

    myTrend.add(totalActionTime);
  } finally {
    await page.close();
  }
}