Discussion: should `ignoreUrls` and `whitelistUrls` affect XHR breadcrumbs?

[benvinegar]

A user has pointed out that it is unfortunate that XHR breadcrumbs can include requests by 3rd-party scripts.

So, I'm thinking that the ignoreUrls and whitelistUrls config options can impact breadcrumb collection. Our docs encourage you to specify base URLs (e.g. domains), so I feel like this is appropriate ... but at the same time, I'm worried that overloading the meaning of these could also become painful. For example, you want to collect errors from your domain, but don't want to collect AJAX breadcrumbs to a reporting endpoint on your domain – if we go this way, there will be no distinguishing.

Other ideas:

• dedicated config option for breadcrumb URLs (could affect both XHRs and nav events)
• a callback function for breadcrumbs (like shouldSendCallback) that allows you to mutate outbound data or cancel recording of an individual event

Thoughts?

cc @mattrobenolt @mitsuhiko

[ksonnad]

As the user, I'd prefer the callback for maximum flexibility. Regexes can't handle every scenario, and the URL isn't the only attribute we may want to examine.

[cudasteve]

For the particular use case that led me to this issue, using ignoreUrls to not collect breadcrumbs from XHR requests to that URL would work well for me. But I agree that it's probably best to keep a distinction in the API between the filter applied to errors and filter applied to XHR breadcrumbs.

For example, in my use case, I WANT to debug everything, but there's certain very frequent API calls that I want to prevent from taking up any of my 20 valuable breadcrumb slots.

[stephen]

I am +1 on a callback for mutating/suppressing outbound xhr breadcrumbs. For our usecase, I'd like to (when available) attach a request id header that's sent back from our api. Currently, we emit a separate breadcrumb with that information, but it'd be nice to have a supported way to do that.

[cudasteve]

A breadcrumb mutate/suppress callback could be really useful in another way too. You could use it to create really descriptive breadcrumbs by letting the implementer turn a Sentry-generated "ui.click button#buy-more-stuff-18462816" into "Clicked Buy Now button"

[benvinegar]

We added a breadcrumbCallback config option in #788, so I think this ticket can be closed.