[DEBUG-2503] Add support for span code origin

[watson]

What does this PR do?

This PR adds support for a new feature called "Code Origin for Spans" (previously called "Span Origin"). This feature will, in its most basic form, allow users to see where in their code base a span was started/created.

To enable, set DD_TRACE_SPAN_ORIGIN_ENABLED=true.

By default, code origin is only set for spans whos callstack contains user land stack frames.

To support code origin on entry spans (i.e. the span automatically created when an incoming HTTP request is being instrumented), one would need to add this to the router instrumentation for each web framework. This PR includes support for code origin on Fastify entry spans only.

For reference, here's a PR that implements Code Origin in the Java tracer: DataDog/dd-trace-java#7001

Motivation

This makes it easier to understand what each span shown in the flame graph represents.

Tasks

• Support more frameworks for entry spans, than just Fastify
• Change how the code origin feature is enabled according to the RFC
• Rename tags according to newly decided API once the server supports the new tags
• Add documentation
• Improve test coverage
• Code cleanup
• Benchmarks?

[github-actions]

Overall package size

Self size: 6.86 MB
Deduped: 58.36 MB
No deduping: 58.64 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/native-appsec | 8.0.1 | 15.59 MB | 15.6 MB | | @datadog/native-iast-taint-tracking | 3.0.0 | 11.14 MB | 11.15 MB | | @datadog/pprof | 5.3.0 | 9.85 MB | 10.22 MB | | protobufjs | 7.2.5 | 2.77 MB | 6.56 MB | | @datadog/native-iast-rewriter | 2.3.1 | 2.15 MB | 2.24 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 | 1.8.1 | 71.67 kB | 785.15 kB | | msgpack-lite | 0.1.26 | 201.16 kB | 281.59 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 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 | | lru-cache | 7.14.0 | 74.95 kB | 74.95 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 | | 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 | | path-to-regexp | 0.1.7 | 6.78 kB | 6.78 kB | | koalas | 1.0.2 | 6.47 kB | 6.47 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: 2024-07-19 13:25:37

Comparing candidate commit 297bdfa in PR branch watson/span-origin with baseline commit 1cf552f in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 258 metrics, 8 unstable metrics.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.19%. Comparing base (2c1367b) to head (cf52e47).
Report is 4 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #4449       +/-   ##
===========================================
- Coverage   93.38%   69.19%   -24.20%     
===========================================
  Files         100        1       -99     
  Lines        3160      198     -2962     
  Branches       33       33               
===========================================
- Hits         2951      137     -2814     
+ Misses        209       61      -148     

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[watson]

• [DEBUG-2503] Add support for span code origin #4449 👈
• master

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