Merge pull request #1430 from grafana/update-k6-browser-examples

docs: add a few more k6 browser examples

docs/sources/next/javascript-api/k6-experimental/browser/browsercontext/newpage.md

@@ -21,7 +21,8 @@ Uses the `BrowserContext` to create a new [Page](https://grafana.com/docs/k6/<K6
 import { browser } from 'k6/experimental/browser';
 
 export default async function () {
-  const page = browser.newPage();
+  const context = browser.newContext();
+  const page = context.newPage();
 
   try {
     await page.goto('https://test.k6.io/browser.php');

docs/sources/next/using-k6-browser/metrics.md

@@ -98,3 +98,73 @@ When the test is run, you should see a similar output as the one below.
 ✓ browser_web_vital_lcp..........................: avg=460.1ms  min=460.1ms  med=460.1ms  max=460.1ms  p(90)=460.1ms  p(95)=460.1ms
   browser_web_vital_ttfb.........................: avg=339.3ms  min=258.9ms  med=339.3ms  max=419.7ms  p(90)=403.62ms p(95)=411.66ms
 ```
+
+## Measure custom metrics
+
+When using the k6 browser `page.evaluate` function, you can call the [Performance API](https://developer.mozilla.org/en-US/docs/Web/API/Performance_API) to measure the performance of web applications. For example, if you want to measure the time it takes for your users to complete actions, such as a search feature, you can use the [`performance.mark`](https://developer.mozilla.org/en-US/docs/Web/API/Performance/mark) method to add a timestamp in your browser's performance timeline. 
+		
+Using the [`performance.measure`](https://developer.mozilla.org/en-US/docs/Web/API/Performance/measure) method, you can also measure the time difference between two performance markers. The time duration that `performance.measure` returns can be added as a custom metric in k6 browser using [Trends](https://k6.io/docs/javascript-api/k6-metrics/trend/).
+
+{{< code >}}
+
+```javascript
+import { browser } from "k6/experimental/browser";
+import { Trend } from "k6/metrics";
+
+export const options = {
+  scenarios: {
+    ui: {
+      executor: "shared-iterations",
+      options: {
+        browser: {
+          type: "chromium",
+        },
+      },
+    },
+  },
+};
+
+const myTrend = new Trend('total_action_time');
+
+export default async function () {
+  const page = browser.newPage();
+
+  try {
+    await page.goto('https://test.k6.io/browser.php');
+    page.evaluate(() => window.performance.mark('page-visit'));
+
+    page.locator('#checkbox1').check();
+    page.locator('#counter-button"]').click();
+    page.locator('#text1').fill('This is a test');
+
+    page.evaluate(() => window.performance.mark('action-completed'));
+
+    // Get time difference between visiting the page and completing the actions
+    page.evaluate(() =>
+      window.performance.measure(
+        'total-action-time',
+        'page-visit',
+        'action-completed',
+      )
+    );
+
+    const totalActionTime = page.evaluate(() =>
+      JSON.parse(JSON.stringify(window.performance.getEntriesByName('total-action-time')))[0].duration
+    );
+
+    myTrend.add(total_action_time);
+  } finally {
+    page.close();
+  }
+}
+```
+
+{{< /code >}}
+
+After you run the test, you should see a similar output as the one below.
+
+```bash
+  iteration_duration..........: avg=1.06s    min=1.06s    med=1.06s    max=1.06s    p(90)=1.06s    p(95)=1.06s
+  iterations..................: 1      0.70866/s
+  total_action_time.............: avg=295.3    min=295.3    med=295.3    max=295.3    p(90)=295.3    p(95)=295.3
+```

docs/sources/next/using-k6-browser/recommended-practices/_index.md

@@ -9,5 +9,6 @@ weight: 100
 
 This section presents some examples and recommended practices when working with the `k6 browser` module to leverage browser automation as part of your k6 tests.
 
+- [Hybrid approach to performance](https://grafana.com/docs/k6/<K6_VERSION>/using-k6-browser/recommended-practices/hybrid-approach-to-performance)
 - [Page object model pattern](https://grafana.com/docs/k6/<K6_VERSION>/using-k6-browser/recommended-practices/page-object-model-pattern)
 - [Selecting elements](https://grafana.com/docs/k6/<K6_VERSION>/using-k6-browser/recommended-practices/selecting-elements)

docs/sources/next/using-k6-browser/recommended-practices/hybrid-approach-to-performance.md

@@ -0,0 +1,197 @@
+---
+title: 'Hybrid approach to performance'
+heading: 'Hybrid performance with k6 browser'
+head_title: 'Hybrid performance with k6 browser'
+excerpt: 'An example on how to implement a hybrid approach to performance with k6 browser'
+weight: 01
+---
+
+# Hybrid performance with k6 browser
+
+An alternative approach to [browser-based load testing](https://grafana.com/docs/k6/<K6_VERSION>/testing-guides/load-testing-websites/#browser-based-load-testing) that's much less resource-intensive is combining a small number of virtual users for a browser test with a large number of virtual users for a protocol-level test. 
+
+You can achieve hybrid performance in multiple ways, often by using different tools. To simplify the developer experience, you can combine k6 browser with core k6 features to write hybrid tests in a single script. 
+
+## Browser and HTTP test
+
+The code below shows an example of combining a browser and HTTP test in a single script. While the script exposes the backend to the typical load, it also checks the frontend for any unexpected issues. It also defines thresholds to check both HTTP and browser metrics against pre-defined SLOs.
+
+{{< code >}}
+
+```javascript
+import http from "k6/http";
+import { check } from "k6";
+import { browser } from "k6/experimental/browser";
+
+const BASE_URL = __ENV.BASE_URL;
+
+export const options = {
+  scenarios: {
+    load: {
+      exec: 'getPizza',
+      executor: 'ramping-vus',
+      stages: [
+        { duration: '5s', target: 5 },
+        { duration: '10s', target: 5 },
+        { duration: '5s', target: 0 },
+      ],
+      startTime: '10s',
+    },
+    browser: {
+      exec: 'checkFrontend',
+      executor: 'constant-vus',
+      vus: 1,
+      duration: '30s',
+        options: {
+          browser: {
+            type: 'chromium',
+          },
+      },
+    }
+  },
+  thresholds: {
+    http_req_failed: ['rate<0.01'],
+    http_req_duration: ['p(95)<500', 'p(99)<1000'],
+    browser_web_vital_fcp: ["p(95) < 1000"],
+    browser_web_vital_lcp: ["p(95) < 2000"],
+  },
+};
+
+export function getPizza() {
+  let restrictions = {
+    maxCaloriesPerSlice: 500,
+    mustBeVegetarian: false,
+    excludedIngredients: ['pepperoni'],
+    excludedTools: ['knife'],
+    maxNumberOfToppings: 6,
+    minNumberOfToppings: 2
+  }
+
+  let res = http.post(`${BASE_URL}/api/pizza`, JSON.stringify(restrictions), {
+    headers: {
+      'Content-Type': 'application/json',
+      'X-User-ID': customers[Math.floor(Math.random() * customers.length)],
+    },
+  });
+
+  check(res, { 
+    'status is 200': (res) => res.status === 200 
+  });
+}
+
+export async function checkFrontend() {
+  const page = browser.newPage();
+
+  try {
+    await page.goto(BASE_URL)
+    check(page, {
+      'header': page.locator('h1').textContent() == 'Looking to break out of your pizza routine?',
+    });
+
+    await page.locator('//button[. = "Pizza, Please!"]').click();
+    page.waitForTimeout(500);
+    page.screenshot({ path: `screenshots/${__ITER}.png` });
+
+    check(page, {
+      'recommendation': page.locator('div#recommendations').textContent() != '',
+    });
+  } finally {
+    page.close();
+  }
+}
+
+```
+
+{{< /code >}}
+
+## Browser and failure injection test
+
+You can also run a browser test together with a failure injection test by using the [xk6-disruptor](https://github.com/grafana/xk6-disruptor) extension. This approach lets you find issues in your front end if any services it depends on are suddenly injected with failures, such as delays or server errors.
+
+The following code shows an example of how to introduce faults to a Kubernetes service. At the same time, the `browser` scenario runs to ensure the frontend application is free of any unexpected errors that may not have been handled properly.
+
+To find out more information about injecting faults to your service, check out the [Get started with xk6-disruptor guide](https://grafana.com/docs/k6/<K6_VERSION>/javascript-api/xk6-disruptor/get-started/).
+
+{{< code >}}
+
+```javascript
+import http from "k6/http";
+import { check } from "k6";
+import { browser } from "k6/experimental/browser";
+
+const BASE_URL = __ENV.BASE_URL;
+
+export const options = {
+  scenarios: {
+    disrupt: {
+      executor: "shared-iterations",
+      iterations: 1,
+      vus: 1,
+      exec: "disrupt",
+    },
+    browser: {
+      executor: "constant-vus",
+      vus: 1,
+      duration: "10s",
+      startTime: "10s",
+      exec: "browser",
+      options: {
+        browser: {
+          type: "chromium",
+        },
+      },
+    },
+  },
+  thresholds: {
+    browser_web_vital_fcp: ["p(95) < 1000"],
+    browser_web_vital_lcp: ["p(95) < 2000"],
+  },
+};
+
+// Add faults to the service by introducing a delay of 1s and 503 errors to 10% of the requests.
+const fault = {
+  averageDelay: "1000ms",
+  errorRate: 0.1,
+  errorCode: 503,
+}
+
+export function disrupt() {
+  const disruptor = new ServiceDisruptor("pizza-info", "pizza-ns");
+  const targets = disruptor.targets();
+  if (targets.length == 0) {
+    throw new Error("expected list to have one target");
+  }
+
+  disruptor.injectHTTPFaults(fault, "20s");
+}
+
+export async function checkFrontend() {
+  const page = browser.newPage();
+
+  try {
+    await page.goto(BASE_URL)
+    check(page, {
+      'header': page.locator('h1').textContent() == 'Looking to break out of your pizza routine?',
+    });
+
+    await page.locator('//button[. = "Pizza, Please!"]').click();
+    page.waitForTimeout(500);
+    page.screenshot({ path: `screenshots/${__ITER}.png` });
+
+    check(page, {
+      'recommendation': page.locator('div#recommendations').textContent() != '',
+    });
+  } finally {
+    page.close();
+  }
+}
+
+```
+
+{{< /code >}}
+
+## Recommended practices
+
+- **Start small**. Start with a small number of browser-based virtual users. A good starting point is to have 10% virtual users or less to monitor the user experience for your end-users, while the script emulates around 90% of traffic from the protocol level.
+- **Combine browser test with different load testing types**. To fully understand the impact of different traffic patterns on your end-user experience, experiment with running your browser test with different [load testing types](https://grafana.com/docs/k6/<K6_VERSION>/testing-guides/test-types/).
+- **Focus on high-risk user journeys as a start**. Identify the high-risk user journeys first so you can start monitoring the web performance metrics for them while your backend applications are being exposed to high traffic or service faults.

docs/sources/next/using-k6-browser/recommended-practices/page-object-model-pattern.md

@@ -3,7 +3,7 @@ title: 'Page object model'
 heading: 'Page object model with k6 browser'
 head_title: 'Page object model with k6 browser'
 excerpt: 'An example on how to implement page object model design pattern with k6 browser'
-weight: 01
+weight: 02
 ---
 
 # Page object model

docs/sources/next/using-k6-browser/recommended-practices/selecting-elements.md

@@ -1,7 +1,7 @@
 ---
 title: 'Selecting elements'
 excerpt: 'A guide on how to select elements with the browser module.'
-weight: 02
+weight: 03
 ---
 
 # Selecting elements

docs/sources/v0.47.x/javascript-api/k6-experimental/browser/browsercontext/newpage.md

@@ -21,7 +21,8 @@ Uses the `BrowserContext` to create a new [Page](https://grafana.com/docs/k6/<K6
 import { browser } from 'k6/experimental/browser';
 
 export default async function () {
-  const page = browser.newPage();
+  const context = browser.newContext();
+  const page = context.newPage();
 
   try {
     await page.goto('https://test.k6.io/browser.php');

docs/sources/v0.47.x/using-k6-browser/metrics.md

@@ -98,3 +98,73 @@ When the test is run, you should see a similar output as the one below.
 ✓ browser_web_vital_lcp..........................: avg=460.1ms  min=460.1ms  med=460.1ms  max=460.1ms  p(90)=460.1ms  p(95)=460.1ms
   browser_web_vital_ttfb.........................: avg=339.3ms  min=258.9ms  med=339.3ms  max=419.7ms  p(90)=403.62ms p(95)=411.66ms
 ```
+
+## Measure custom metrics
+
+When using the k6 browser `page.evaluate` function, you can call the [Performance API](https://developer.mozilla.org/en-US/docs/Web/API/Performance_API) to measure the performance of web applications. For example, if you want to measure the time it takes for your users to complete actions, such as a search feature, you can use the [`performance.mark`](https://developer.mozilla.org/en-US/docs/Web/API/Performance/mark) method to add a timestamp in your browser's performance timeline. 
+		
+Using the [`performance.measure`](https://developer.mozilla.org/en-US/docs/Web/API/Performance/measure) method, you can also measure the time difference between two performance markers. The time duration that `performance.measure` returns can be added as a custom metric in k6 browser using [Trends](https://k6.io/docs/javascript-api/k6-metrics/trend/).
+
+{{< code >}}
+
+```javascript
+import { browser } from "k6/experimental/browser";
+import { Trend } from "k6/metrics";
+
+export const options = {
+  scenarios: {
+    ui: {
+      executor: "shared-iterations",
+      options: {
+        browser: {
+          type: "chromium",
+        },
+      },
+    },
+  },
+};
+
+const myTrend = new Trend('total_action_time');
+
+export default async function () {
+  const page = browser.newPage();
+
+  try {
+    await page.goto('https://test.k6.io/browser.php');
+    page.evaluate(() => window.performance.mark('page-visit'));
+
+    page.locator('#checkbox1').check();
+    page.locator('#counter-button"]').click();
+    page.locator('#text1').fill('This is a test');
+
+    page.evaluate(() => window.performance.mark('action-completed'));
+
+    // Get time difference between visiting the page and completing the actions
+    page.evaluate(() =>
+      window.performance.measure(
+        'total-action-time',
+        'page-visit',
+        'action-completed',
+      )
+    );
+
+    const totalActionTime = page.evaluate(() =>
+      JSON.parse(JSON.stringify(window.performance.getEntriesByName('total-action-time')))[0].duration
+    );
+
+    myTrend.add(total_action_time);
+  } finally {
+    page.close();
+  }
+}
+```
+
+{{< /code >}}
+
+After you run the test, you should see a similar output as the one below.
+
+```bash
+  iteration_duration..........: avg=1.06s    min=1.06s    med=1.06s    max=1.06s    p(90)=1.06s    p(95)=1.06s
+  iterations..................: 1      0.70866/s
+  total_action_time.............: avg=295.3    min=295.3    med=295.3    max=295.3    p(90)=295.3    p(95)=295.3
+```