Allow a url path name for lazyLoadIntegration / cdnBaseUrl

[TheDelta]

Problem Statement

I implemented latest sentry-js into an angular application and noticed some issues (going to open a discussion about this soon).

During that integration, I wanted to use lazyLoadIntegration with cdnBaseUrl to my self hosted sentry instance.
I created an issue on the on premise repo getsentry/self-hosted#3777 and it might be helpful for some context and my motivation.

The key issue atm is, that the self hosted instance serves the client files under a sub path, like https://sentry.example.test/js-sdk/.
I'm totally aware that this is more likely a on-premise issue and could also be fixed by the user with some custom proxy url, but I wanted to highlight this issue anyways so that a dev could have a look at this.

cdnBaseUrl (which is totally correct btw!) only works with a base url:

sentry-javascript/packages/browser/src/utils/lazyLoadIntegration.ts

Line 97 in 062204a

const baseURL = client?.getOptions()?.cdnBaseUrl || 'https://browser.sentry-cdn.com';

There is currently no way to use a path, so /js-sdk/ is omitted in the end and it can't fetch the bundle from the on-premise instance.
This is all in theory, because officially the on-premise instance doesn't serve any sub bundles which the lazyLoadIntegration would actually load (thats an issue on the on-premise instance atm).

Long story short: Is it possible to get a feature where the user can define a baseUrl with path or is this beyond what the SDK should support.

Solution Brainstorm

Rewrite the code to use the cdnBaseUrl as URL directly and append the bundle path, or o allow some other variable to define the sub path, like cdnPathName.

cdnBaseUrl: 'https://sentry.example.test',
cdnPathName: '/js-sdk/'

const baseUrlPath = new URL(cdnPathName ?? '', cdnBaseUrl);`
return `${baseUrlPath}/${SDK_VERSION}/${bundle}.min.js`;

[linear]

JS-737 Allow a url path name for lazyLoadIntegration / cdnBaseUrl

[s1gr1d]

Hello, thanks for providing this feature request with some context around it.

Would a function like getScriptUrl work for your use-case as well? Then it would cover a wider range of possibilities.

lazyLoadIntegration('replayIntegration', { 
    getScriptUrl: (bundle) => `https://custom-thing.com/path/${bundle}.js`
});

[TheDelta]

That would be an excellent solution as well and allows more flexibility, although SDK_VERSION would be missing, so this must be imported ourself then.

lazyLoadIntegration('replayIntegration', { 
    getScriptUrl: (bundle) => `https://custom-thing.com/js-sdk/${SDK_VERSION}/${bundle}.js`
});

But this could also serve another use case, where the bundle is shipped with the application itself, e.g. /assets/sentry/replayIntegration.js
I like this 👍

I'm still uncertain what would be the best solution for sentry-javascript + sentry-selfhosted,
eventually this should be discussed within sentry team how to proceed further.
At the moment sentry-selfhosted officially won't support lazy load integration, because these bundles are not available on the self hosted instance.

[s1gr1d]

We can also provide the SDK version as a parameter :)
If you are self-hosted, you also need to host the bundles yourself on your own CDN. As of today, self-hosted instances don't have access to the official Sentry CDN bundles.