vistit: Retry on ENOTFOUND errors

[testerez]

Current behavior:

When using cy.vistit, if the DNS fails to resolve, we get: Error: getaddrinfo ENOTFOUND

Example:

Desired behavior:

In our CI, the DNS is sometimes flaky. Unfortunately, we can't really fix that yet. So it would be nice if cypress offered a way to retry the visit command when we get this kind of errors.

Versions

cypress@3.3.1

[jennifer-shehane]

We recently implemented automatic retrying of cy.visit() in these situations in Cypress 3.3.0, so it has already retried and failed at this point.

Requests that go through cy.visit() or cy.request() are now automatically retried under the hood when the request fails. This more closely reflects Chrome’s default behavior on requests. Addresses #4013, #898 and #1013.

@flotwig We mention that we retried the cy.visit() in the CLI log when it fails on baseUrl, shouldn't we also mention we retried the cy.visit() in the Command Log here?

You can implement rerunning the commands/tests when they fail using the cypress-plugin-retires mentioned here. #1313 (comment)

I'm afraid this is all we can recommend in this situation.

[testerez]

From a quick test, it does not look like Cypress retries in this specific situation. You can easily reproduce with:

it('will fail instantly with ENOTFOUND', () => {
  cy.visit('http://foo.localhost');
});

When I try this, Cypress fails instantly (0.21s):

[flotwig]

We initially left out retrying on ENOTFOUND because we thought this scenario didn't exist in the wild (flaky DNS???), but it can definitely be added.

[testerez]

Cool thank you @flotwig! To be honest I'm not entirely sure why we have this issue. But it happens when our CI deploys an ephemeral to test against. We do wait until the deployment is ready before starting the Cypress tests but sometimes we still get this intermittent ENOTFOUND error. Maybe the record is not yet propagated everywhere. Anyway, if Cypress could just retry when we get this error it would be a quick fix for us.

[flotwig]

Actually found another instance of this DNS flakiness, so I guess it's not as rare as we thought: #1755

[cypress-bot]

The code for this is done in cypress-io/cypress#4459, but has yet to be released.
We'll update this issue and reference the changelog when it's released.

[cypress-bot]

Released in 3.3.2.

[pardeeprj90]

Error: getaddrinfo ENOTFOUND vfolpuat.ctdi.com

still, issue exists, the same code was working previously fine.

[jennifer-shehane]

This issue will be closed to further comment as the exact issue here was resolved and tested.

@pardeeprj90 If you're experiencing a bug similar to this in Cypress, please open a new issue with a fully reproducible example that we can run. There may be a specific edge case with the issue that we need more detail to fix.