Sentry: Sentry JS lazily-loadable loader doesn't work

[fabis94]

Version Information

Version: 20.10.1

Description

According to the documentation (https://docs.sentry.io/platforms/javascript/install/lazy-load-sentry/#sdk-version) Sentry offers a lightweight lazy-loadable version of the Sentry JS SDK which is a lot smaller than the default bundles.

I tried to use it, but when I open the script that's shown inside the "JavaScript Loader" input box as shown in the docs, the entire contents of the script look like this:

function _sentry_noopWarning() {
  console.warn("The Sentry loader you are trying to use isn't working anymore, check your configuration.");
}
var Sentry = {
    addBreadcrumb: _sentry_noopWarning,
    captureEvent: _sentry_noopWarning,
    captureException: _sentry_noopWarning,
    captureMessage: _sentry_noopWarning,
    configureScope: _sentry_noopWarning,
    forceLoad: _sentry_noopWarning,
    init: _sentry_noopWarning,
    onLoad: _sentry_noopWarning,
    showReportDialog: _sentry_noopWarning,
    withScope: _sentry_noopWarning,
};
_sentry_noopWarning();

I tried grep-ing through the Sentry source code about this, but I was only able to find the template that generates this script (https://github.com/getsentry/sentry/blob/master/src/sentry/templates/sentry/js-sdk-loader-noop.js.tmpl) and couldn't figure out further how does Sentry decide to show this broken version instead of the real script.

The documentation isn't helpful either.

Steps to Reproduce

Install Sentry on-premises and check the JavaScript Loader, I guess.

Logs

No logs

[BYK]

Hi, I think this is intended to be used by https://sentry.io or when you are using a CDN yourself. The definitions are here: https://github.com/getsentry/sentry/blob/c3da5bd066b6f30358a455b78eab4ba075c0acf9/src/sentry/conf/server.py#L1862-L1870

Can you share where you are seeing this script linked to? Maybe this is just a UI issue that we need to disable for on-premise (or when this setting is not set).

[fabis94]

@BYK Same place it's shown in the docs, in the Client Keys (DSN) settings, when pressing "Configure" on the DSN key.

It would be great if this feature could be used on-premises as well, since there's no other way to lazily load the JS SDK

[BYK]

@fabis94 thanks a lot for the quick turn around! I'll be investigating this.

[christopherowen]

I can confirm that I am seeing this is the latest release of on premise as well.

Like the original poster, I followed the same path and was led to this ticket.

I’d be happy to debug or offer feedback.

[christopherowen]

I've tried a number of attempts at setting system.JS_SDK_LOADER_DEFAULT_SDK_URL in sentry/config.yml and sentry/sentry.conf.py without luck so far.

I receive various versions of "Unknown config option found:" in the logs.

[christopherowen]

I was able to get this working by setting the following in sentry/sentry.conf.py

JS_SDK_LOADER_DEFAULT_SDK_URL = "https://browser.sentry-cdn.com/%s/bundle.tracing.min.js"

May I suggest that this be set as a default in the sentry.conf.example.py?

[fabis94]

@christopherowen Is that really lazy loading, though? It looks like it just loads the standard bundle instead of the specialized lazy-loadable version that is supposedly served by the cloud version of Sentry.

[christopherowen]

yes it is, this url is loaded by the lazy loader.