PROF-10329: Separate SSI telemetry and heuristics activation

[szegedi]

What does this PR do?

Currently DD_PROFILING_ENABLED=auto will trigger SSI telemetry emission, just as if DD_INJECTION_ENABLED=profiler was specified. However, the two are not identical in requirements for emitting telemetry.

• Telemetry should be emitted if and only if DD_INJECTION_ENABLED is defined with any value, and DD_PROFILING_ENABLED=false is not explicitly specified.
• Heuristics should activate if and only if DD_INJECTION_ENABLED=profiler or DD_PROFILING_ENABLED=auto are specified.

We need to separate the two.

• This PR starts off by simplifying the env var configuration around SSI. Instead of _applyEnvironment() deriving values for profiling.ssi and profiling.heuristicsEnabled, it now just mirrors the values for DD_PROFILING_ENABLED and DD_INJECTION_ENABLED. To this end, profiling.enabled is no longer a boolean, as it now needs to support four values (true, false, auto, undefined) instead of three ones (true, false, undefined.) For less confusion around boolean-ey value names, we now use a string with values "enabled", "disabled", and "auto" (while keeping undefined.)
• We completely removed profiling.ssi and profiling.heuristicsEnabled in favor of the now 4-state profiling.enabled and the newly introduced injectionEnabled that is an array of parsed values from DD_INJECTION_ENABLED.
• We touched up telemetry.logCollection as it, too, used to be derived in _applyEnvironment(). Now it got moved to its rightful place in _applyCalculated().
• Finally, we use these new configuration values to revamp ssi-heuristics.js and its uses. We managed to eliminate the frankly unnecessary profiling enabled config too – if profiling is not enabled, we short circuit the path to creating any profiling related objects now in proxy.js.

Motivation

SSI telemetry and heuristics are actually orthogonal concerns. We also need the separation to later cleanly implement the emission of SSI information in profiles' system info.

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-08-12 13:22:16

Comparing candidate commit e8685d9 in PR branch szegedi/four-state-profiling with baseline commit 77c1d07 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 264 metrics, 2 unstable metrics.

[github-actions]

Overall package size

Self size: 6.95 MB
Deduped: 58.17 MB
No deduping: 58.45 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 | 3.1.0 | 12.27 MB | 12.28 MB | | @datadog/pprof | 5.3.0 | 9.85 MB | 10.22 MB | | protobufjs | 7.2.5 | 2.77 MB | 5.16 MB | | @datadog/native-iast-rewriter | 2.4.1 | 2.14 MB | 2.23 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}

[codecov]

Codecov Report

Attention: Patch coverage is 56.92308% with 28 lines in your changes missing coverage. Please review.

Project coverage is 82.83%. Comparing base (77c1d07) to head (df6b40a).

Files	Patch %	Lines
packages/dd-trace/src/profiling/ssi-heuristics.js	30.00%	21 Missing ⚠️
packages/dd-trace/src/proxy.js	66.66%	5 Missing ⚠️
packages/dd-trace/src/config.js	94.73%	1 Missing ⚠️
packages/dd-trace/src/profiler.js	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #4592       +/-   ##
===========================================
+ Coverage   68.33%   82.83%   +14.49%     
===========================================
  Files         254      256        +2     
  Lines       11195    11260       +65     
  Branches       33       33               
===========================================
+ Hits         7650     9327     +1677     
+ Misses       3545     1933     -1612     

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