[ASM] multer instrumentation

[iunanua]

What does this PR do?

multer instrumentation

Motivation

be able to handle multipart request bodies parsed with multer

ST: DataDog/system-tests#3249

Plugin Checklist

• Unit tests.
• TypeScript definitions.
• TypeScript tests.
• API documentation.
• CircleCI jobs/workflows.
• Plugin is exported.

Additional Notes

[github-actions]

Overall package size

Self size: 7.61 MB
Deduped: 64.47 MB
No deduping: 64.81 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/native-appsec | 8.2.1 | 19.18 MB | 19.19 MB | | @datadog/native-iast-taint-tracking | 3.2.0 | 13.9 MB | 13.91 MB | | @datadog/pprof | 5.4.1 | 9.76 MB | 10.13 MB | | protobufjs | 7.2.5 | 2.77 MB | 5.16 MB | | @datadog/native-iast-rewriter | 2.5.0 | 2.51 MB | 2.65 MB | | @opentelemetry/core | 1.14.0 | 872.87 kB | 1.47 MB | | @datadog/native-metrics | 2.0.0 | 898.77 kB | 1.3 MB | | @opentelemetry/api | 1.8.0 | 1.21 MB | 1.21 MB | | import-in-the-middle | 1.11.2 | 112.74 kB | 826.22 kB | | msgpack-lite | 0.1.26 | 201.16 kB | 281.59 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | lru-cache | 7.18.3 | 133.92 kB | 133.92 kB | | pprof-format | 2.1.0 | 111.69 kB | 111.69 kB | | @datadog/sketches-js | 2.1.0 | 109.9 kB | 109.9 kB | | semver | 7.6.3 | 95.82 kB | 95.82 kB | | lodash.sortby | 4.7.0 | 75.76 kB | 75.76 kB | | ignore | 5.3.1 | 51.46 kB | 51.46 kB | | int64-buffer | 0.1.10 | 49.18 kB | 49.18 kB | | shell-quote | 1.8.1 | 44.96 kB | 44.96 kB | | istanbul-lib-coverage | 3.2.0 | 29.34 kB | 29.34 kB | | rfdc | 1.3.1 | 25.21 kB | 25.21 kB | | tlhunter-sorted-set | 0.1.0 | 24.94 kB | 24.94 kB | | limiter | 1.1.5 | 23.17 kB | 23.17 kB | | dc-polyfill | 0.1.4 | 23.1 kB | 23.1 kB | | retry | 0.13.1 | 18.85 kB | 18.85 kB | | jest-docblock | 29.7.0 | 8.99 kB | 12.76 kB | | crypto-randomuuid | 1.0.0 | 11.18 kB | 11.18 kB | | koalas | 1.0.2 | 6.47 kB | 6.47 kB | | path-to-regexp | 0.1.10 | 6.38 kB | 6.38 kB | | module-details-from-path | 1.0.3 | 4.47 kB | 4.47 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-10-25 13:09:26

Comparing candidate commit a19cade in PR branch igor/multer with baseline commit c007354 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 259 metrics, 7 unstable metrics.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.09%. Comparing base (fd0f570) to head (5f48710).
Report is 24 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #4781       +/-   ##
===========================================
+ Coverage   68.58%   98.09%   +29.51%     
===========================================
  Files          12        1       -11     
  Lines         818      105      -713     
===========================================
- Hits          561      103      -458     
+ Misses        257        2      -255     

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[uurien]

why are we checking this multerReadCh.hasSubscribers in line 14 and not here? imo, we should prevent creating AsyncResource when appsec/iast is not enabled.

Suggested change

	const nextResource = new AsyncResource('bound-anonymous-fn')
	arguments[2] = nextResource.bind(publishRequestBodyAndNext(req, res, next))
	if (multerReadCh.hasSubscribers) {
	const nextResource = new AsyncResource('bound-anonymous-fn')
	arguments[2] = nextResource.bind(publishRequestBodyAndNext(req, res, next))
	}

[iunanua]

i was inspired by body-parser instrumentation