k6 browser does not surface browser network errors when navigating to a page #4895
Description
Brief summary
A script that navigates and waits for a page to load will report no error even if Chromium cannot load that page due to a network error.
k6 version
k6 v1.1.0 (go1.24.4, linux/amd64)
OS
Arch linux (btw)
Docker version and image (if applicable)
N/A
Steps to reproduce the problem
Run the following script, provided that nothing is running on localhost:4444 (so connections to that port will fail):
import { browser } from 'k6/browser';
export const options = {
scenarios: {
ui: {
executor: 'shared-iterations',
options: {
browser: {
type: 'chromium',
},
},
},
},
};
export default async function () {
const context = await browser.newContext();
const page = await context.newPage();
const startUrl = 'http://localhost:4444';
try {
await page.goto(startUrl);
await page.waitForLoadState('networkidle');
const myLocator = await page.locator('#something');
// myLocator.click();
} catch (error) {
console.error(error);
} finally {
await page.close();
}
}Expected behaviour
k6 should error out complaining that the page it was asked to navigate to was unreachable.
Actual behaviour
k6 will report somewhat sensical data and exit with success (0):
nadia@Nadiarch curry-admin@Curry
17:58:37 /tmp/nadia $> k6 run repro.js
/\ Grafana /‾‾/
/\ / \ |\ __ / /
/ \/ \ | |/ / / ‾‾\
/ \ | ( | (‾) |
/ __________ \ |_|\_\ \_____/
execution: local
script: repro.js
output: -
scenarios: (100.00%) 1 scenario, 1 max VUs, 10m30s max duration (incl. graceful stop):
* ui: 1 iterations shared among 1 VUs (maxDuration: 10m0s, gracefulStop: 30s)
█ TOTAL RESULTS
EXECUTION
iteration_duration.............................: avg=2.13s min=2.13s med=2.13s max=2.13s p(90)=2.13s p(95)=2.13s
iterations.....................................: 1 0.438437/s
vus............................................: 1 min=1 max=1
vus_max........................................: 1 min=1 max=1
NETWORK
data_received..................................: 0 B 0 B/s
data_sent......................................: 0 B 0 B/s
BROWSER
browser_data_sent..............................: 185 B 81 B/s
WEB_VITALS
browser_web_vital_cls..........................: avg=0 min=0 med=0 max=0 p(90)=0 p(95)=0
browser_web_vital_fcp..........................: avg=36ms min=36ms med=36ms max=36ms p(90)=36ms p(95)=36ms
browser_web_vital_lcp..........................: avg=36ms min=36ms med=36ms max=36ms p(90)=36ms p(95)=36ms
browser_web_vital_ttfb.........................: avg=399.99µs min=399.99µs med=399.99µs max=399.99µs p(90)=399.99µs p(95)=399.99µs
running (00m02.3s), 0/1 VUs, 1 complete and 0 interrupted iterations
ui ✓ [======================================] 1 VUs 00m02.3s/10m0s 1/1 shared iters
If the commented line myLocator.click(); is uncommented, then k6 will return an error:
WARN[0002] Unexpected DevTools server error: context canceled category="ExecutionContext:eval" elapsed="0 ms" source=browser
ERRO[0002] Uncaught (in promise) clicking on "#something": getting injected script: context canceled executor=shared-iterations scenario=ui
The fact that the error is surfaced when an action is performed misleads users to think the problem lies in that action, and not in the page not being loaded in the first place.