Do not init the tracer by default in Worker threads

[uurien]

What does this PR do?

Prevent the tracer init in Worker threads by default.

Motivation

• Can cause unexpected and untested behaviours: Two tracers with the same service name but different ids
• In initialize.mjs we are initializing the tracer only in the main thread: https://github.com/DataDog/dd-trace-js/blob/master/initialize.mjs#L52

Additional Notes

[github-actions]

Overall package size

Self size: 8.49 MB
Deduped: 94.84 MB
No deduping: 95.35 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/libdatadog | 0.4.0 | 29.44 MB | 29.44 MB | | @datadog/native-appsec | 8.4.0 | 19.25 MB | 19.26 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 | 2.6.1 | 2.59 MB | 2.73 MB | | @opentelemetry/core | 1.14.0 | 872.87 kB | 1.47 MB | | @datadog/native-metrics | 3.1.0 | 1.06 MB | 1.46 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 | | source-map | 0.7.4 | 226 kB | 226 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 | | 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 | | @isaacs/ttlcache | 1.4.1 | 25.2 kB | 25.2 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 | 0.1.12 | 6.6 kB | 6.6 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: 2025-01-17 16:08:41

Comparing candidate commit 6102f21 in PR branch ugaitz/do-not-init-in-wt-bydefault with baseline commit 3b8a6b9 in branch master.

Found 1 performance improvements and 1 performance regressions! Performance is the same for 904 metrics, 27 unstable metrics.

scenario:appsec-iast-with-vulnerability-iast-enabled-always-active-22

• 🟩 max_rss_usage [-10.929MB; -8.176MB] or [-8.110%; -6.067%]

scenario:startup-with-tracer-20

• 🟥 cpu_user_time [+12.532ms; +21.022ms] or [+5.237%; +8.784%]

[juan-fernandez]

@uurien could you to add this logic to ci/init.js as well? I'm just curious whether the newest DI + Test optimization logic would work with this change.

Also: are we worried at all about this being a breaking change?

[uurien]

Also: are we worried at all about this being a breaking change?

As we are checking that in initialize.mjs I consider this change more a fix rather than a breaking change.

[watson]

@uurien Most of the Dynamic Instrumentation code runs in Worker Thread. It doesn't need to instrument the code in the Worker Thread, but it expects to access certain parts of the tracer - e.g. the logger. I can see that debugger tests are failing. Let me know if you need my input or review on this PR.