fix(fastify): Make sure consturctor patching works with esm

[mydea]

Which problem is this PR solving?

instrumentation-fastify does not work in ESM mode. This PR fixes this so that fastify can be instrumented when using esm.

The underlying problem is that in ESM mode, the moduleExports is not === the fastify constructor. Instead, this can only be found under the default key.

Short description of the changes

This changes the wrapping behavior to always use the named fastify export, which should always exist.

Fixes #1519

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: mydea / name: Francesco Novy (d052a1b, cbffbc7, b44e566, cc236cf)
• ✅ login: pichlermarc / name: Marc Pichler (51e4857)
• ✅ login: blumamir / name: Amir Blum (cbf00b2)

[Flarna]

Is there an impact to commonjs users using fastify like this (copied from fastify docs)?

const fastify = require('fastify')({
  logger: true
})

[mydea]

Is there an impact to commonjs users using fastify like this (copied from fastify docs)?

const fastify = require('fastify')({
  logger: true
})

I've tried it in a small test app of mine where both syntaxes continue to work for CJS, but would appreciate if somebody else could also give it a go (due to the "mysterious" ways that these things sometimes work 😅 )

[codecov]

Codecov Report

Merging #1624 (cbf00b2) into main (d9cd8d7) will not change coverage.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1624   +/-   ##
=======================================
  Coverage   91.77%   91.77%           
=======================================
  Files         139      139           
  Lines        7112     7112           
  Branches     1427     1427           
=======================================
  Hits         6527     6527           
  Misses        585      585           

Files Changed	Coverage Δ
...try-instrumentation-fastify/src/instrumentation.ts	97.60% <100.00%> (ø)

[pichlermarc]

@mydea thank you for your contribution. Would you mind signing the CLA? Then we can proceed with the PR. 🙂

[mydea]

@mydea thank you for your contribution. Would you mind signing the CLA? Then we can proceed with the PR. 🙂

Done!

[pichlermarc]

Is there an impact to commonjs users using fastify like this (copied from fastify docs)?

const fastify = require('fastify')({
  logger: true
})

I've tried it in a small test app of mine where both syntaxes continue to work for CJS, but would appreciate if somebody else could also give it a go (due to the "mysterious" ways that these things sometimes work 😅 )

Looks good, thanks! 🙂 I also checked and it seems to work for me too.

It seems to need some adjustments so that prettier succeeds, though (see here, you can also run npm run lint from the plugins/node/opentelemetry-instrumentation-fastify/ to check locally), then this should be good to go 🙂

[mydea]

Is there an impact to commonjs users using fastify like this (copied from fastify docs)?

const fastify = require('fastify')({
  logger: true
})

I've tried it in a small test app of mine where both syntaxes continue to work for CJS, but would appreciate if somebody else could also give it a go (due to the "mysterious" ways that these things sometimes work 😅 )

Looks good, thanks! 🙂 I also checked and it seems to work for me too.

It seems to need some adjustments so that prettier succeeds, though (see here, you can also run npm run lint from the plugins/node/opentelemetry-instrumentation-fastify/ to check locally), then this should be good to go 🙂

ah, right, I ran npm run lint:fix and pushed the fix!