feat(sveltekit): Add option to control handling of unknown server routes

[Lms24]

This PR adds a handleUnknownRoutes option to the sentryHandle server request handler. The option defaults to false which would effectively reduce noise, such as random bot requests. Previously such requests would yield e.g. GET null transactions because they could not be matched to an existing route by the framework. See #8199

Note: Users can right now also drop these transactions in ignoreTransactions or beforeSendTransaction but I think we should pre-filter them by default but give them the option to still monitor such requests if they choose to do so.:

Example:

Users register a custom handler (or a handler from a library)

// hooks.server.js

export const handler = sequence(
  sentryHandle(),
  async ({event, resolve}) => {
    if (event.url.pathname.startsWith('/ext-api/auth') { // <-- this endpoint does not exist as a route
      return await getResponseFromExternalAuthService(event.request);
    }
    return resolve(event) 
  }
)

which "understands" requests that are not mapped to a SvelteKit route. This request would not lead to a transaction, unless handleUnknownRoutes was set to true.

resolves #8199

[Lms24]

This we should do regardless of if we want that option or not.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	21.03 KB (+0.05% 🔺)
@sentry/browser - ES5 CDN Bundle (minified)	65.68 KB (+0.09% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	19.58 KB (+0.11% 🔺)
@sentry/browser - ES6 CDN Bundle (minified)	58.15 KB (+0.12% 🔺)
@sentry/browser - Webpack (gzipped + minified)	21.2 KB (+0.15% 🔺)
@sentry/browser - Webpack (minified)	69.07 KB (+0.05% 🔺)
@sentry/react - Webpack (gzipped + minified)	21.22 KB (+0.16% 🔺)
@sentry/nextjs Client - Webpack (gzipped + minified)	49.16 KB (+0.09% 🔺)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	28.67 KB (+0.09% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	26.9 KB (+0.1% 🔺)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	48.25 KB (+1.33% 🔺)
@sentry/replay - Webpack (gzipped + minified)	42.1 KB (+1.55% 🔺)
@sentry/browser + @sentry/tracing + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	67.22 KB (+1.08% 🔺)
@sentry/browser + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	60.11 KB (+1.24% 🔺)

[lforst]

Is there a way to determine a name for these transactions automatically? Maybe there's something on the event to serve as a sensible parameterized default? Didn't check but still wanted to ask ^^

[Lms24]

Not that I'm aware of. I don't think there's anything better that's on all these requests we can fall back to than the URL pathname.

[Lms24]

I updated the description with a better example for future reference.