feat(remix): Export a manual wrapper for custom Express servers.

[onurtemizkan]

Remix allows custom server declarations and exports createRequestHandler functions from each adapter. In some cases, createRequestHandler functions are used before we have a chance to instrument them.

Auto-instrumentation wraps the core createRequestHandler from @remix/server-runtime, which all the adapters use. Each adapter may have their own APIs, so we can't directly re-export our already implemented wrapper.

This PR implements and exports a manual wrapper for Express adapters.

Also:

• Moves Remix-related type declarations to its own file, as it seems it will continue to grow.

One thing I noticed:
A custom express server is still instrumented if it runs on the same thread as the runtime. For example, the tests run on a single Jest thread, and we can't reproduce this because of that.

If this wrapper is used when it's not needed, loader, action and documentRequest spans are reported twice. Is there a preferred way to prevent multiple wrapping? (I saw __sentry_wrapped__ but don't know if that's applicable here.)

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	19.39 KB (+0.02% 🔺)
@sentry/browser - ES5 CDN Bundle (minified)	59.99 KB (0%)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	17.96 KB (+0.01% 🔺)
@sentry/browser - ES6 CDN Bundle (minified)	52.88 KB (0%)
@sentry/browser - Webpack (gzipped + minified)	19.73 KB (0%)
@sentry/browser - Webpack (minified)	64.21 KB (0%)
@sentry/react - Webpack (gzipped + minified)	19.75 KB (0%)
@sentry/nextjs Client - Webpack (gzipped + minified)	44.16 KB (0%)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	25.79 KB (0%)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	24.04 KB (+0.01% 🔺)

[AbhiPrasad]

If this wrapper is used when it's not needed, loader, action and documentRequest spans are reported twice. Is there a preferred way to prevent multiple wrapping

We should be able to use __sentry_wrapped__ - just set it on the wrapped function so we don't wrap multiple times. We could also just store some flags internally, and flip them the first time we wrap - then we can just check those again.

[onurtemizkan]

@AbhiPrasad, the updated tests do not test the manual wrapper by itself. (As I could not recreate the scenario with the current testing structure). But they are testing when we use a manual wrapper on an already instrumented backend.

[AbhiPrasad]

@onurtemizkan That should be fine, we can also dogfood with vanguard to make sure we have added confidence.

[justinwaite]

Great timing for my company as we are currently implementing Sentry in our newest app which happens to be using Remix (wrapped by express 😄). Looking forward to the next release!

[AbhiPrasad]

Awesome news @justinwaite - we’ll have a release out early next week!

@onurtemizkan We’ll need to add some docs, can you take care of that?