chore(distributed_tracing): ensure last datadog parent id tag is always set

[mabdinur]

Implements W3C Phase 3. The last datadog parent id is always propagated in a distributed trace (if ddtrace propagation style includes tracecontext). This change will reduce instances where flamegraphs contain missing spans.

Note - This change does not require a release note. It is a follow up to a previous PR.

Follow up to: 90a3e3f#diff-18af2a7682cf3014ab4ae236fc54d2454bbf5293e81e098b1d22d39bdb61012d

Checklist

• Change(s) are motivated and described in the PR description
• Testing strategy is described if automated tests are not included in the PR
• Risks are described (performance impact, potential for breakage, maintainability)
• Change is maintainable (easy to change, telemetry, documentation)
• Library release note guidelines are followed or label changelog/no-changelog is set
• Documentation is included (in-code, generated user docs, public corp docs)
• Backport labels are set (if applicable)
• If this PR changes the public interface, I've notified @DataDog/apm-tees.

Reviewer Checklist

• Title is accurate
• All changes are related to the pull request's stated goal
• Description motivates each change
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Change is maintainable (easy to change, telemetry, documentation)
• Release note makes sense to a user of the library
• Author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: munir/w3c-changes-2-3
Commit report: 4c903e6
Test service: dd-trace-py

✅ 0 Failed, 129678 Passed, 42213 Skipped, 3h 40m 38.59s Total duration (6h 34m 49.08s time saved)
❄️ 1 New Flaky

New Flaky Tests (1)

• test_extract_traceparent[invalid_0_value_for_span_id] - test_propagation.py - Last Failure

  Expand for error

   'NoneType' object is not iterable
  

[brettlangdon]

Note - This change does not require a release note. It is a follow up to a previous PR.

@mabdinur which PR?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 50.00000% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 6.74%. Comparing base (3ea8bd8) to head (db78bff).
Report is 5 commits behind head on main.

Files	Patch %	Lines
ddtrace/propagation/http.py	60.00%	2 Missing ⚠️
ddtrace/internal/constants.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #9174       +/-   ##
===========================================
- Coverage   78.55%    6.74%   -71.82%     
===========================================
  Files        1273     1244       -29     
  Lines      120300   118571     -1729     
===========================================
- Hits        94496     7992    -86504     
- Misses      25804   110579    +84775     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[mabdinur]

Note - This change does not require a release note. It is a follow up to a previous PR.

@mabdinur which PR?

This change: 90a3e3f#diff-18af2a7682cf3014ab4ae236fc54d2454bbf5293e81e098b1d22d39bdb61012d.

[brettlangdon]

comment nit, otherwise lgtm

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-05-07 20:51:00

Comparing candidate commit 4c903e6 in PR branch munir/w3c-changes-2-3 with baseline commit dac8aa2 in branch main.

Found 20 performance improvements and 27 performance regressions! Performance is the same for 162 metrics, 9 unstable metrics.

scenario:coreapiscenario-context_with_data_listeners

• 🟥 max_rss_usage [+898.497KB; +966.821KB] or [+4.372%; +4.704%]

scenario:coreapiscenario-context_with_data_no_listeners

• 🟩 max_rss_usage [-808.113KB; -599.272KB] or [-3.770%; -2.796%]

scenario:coreapiscenario-core_dispatch_listeners

• 🟩 max_rss_usage [-802.151KB; -637.184KB] or [-3.736%; -2.968%]

scenario:coreapiscenario-core_dispatch_listeners_and_all_listeners

• 🟥 max_rss_usage [+494.013KB; +709.802KB] or [+2.368%; +3.403%]

scenario:coreapiscenario-core_dispatch_no_listeners

• 🟥 max_rss_usage [+660.192KB; +714.425KB] or [+3.269%; +3.538%]

scenario:coreapiscenario-core_dispatch_only_all_listeners

• 🟩 max_rss_usage [-807.441KB; -647.867KB] or [-3.762%; -3.018%]

scenario:coreapiscenario-get_item_exists

• 🟩 max_rss_usage [-586.797KB; -434.336KB] or [-2.741%; -2.029%]

scenario:coreapiscenario-get_item_missing

• 🟩 max_rss_usage [-570.038KB; -517.040KB] or [-2.658%; -2.411%]

scenario:flasksimple-appsec-get

• 🟥 max_rss_usage [+927.182KB; +1029.067KB] or [+2.722%; +3.021%]

scenario:flasksimple-appsec-post

• 🟥 max_rss_usage [+867.455KB; +988.033KB] or [+2.547%; +2.901%]

scenario:httppropagationextract-b3_headers

• 🟥 max_rss_usage [+536.343KB; +758.813KB] or [+2.586%; +3.659%]

scenario:httppropagationextract-datadog_tracecontext_tracestate_propagated_on_trace_id_match

• 🟥 max_rss_usage [+665.699KB; +1179.139KB] or [+3.249%; +5.755%]

scenario:httppropagationextract-full_t_id_datadog_headers

• 🟥 max_rss_usage [+451.752KB; +712.332KB] or [+2.166%; +3.415%]

scenario:httppropagationextract-invalid_priority_header

• 🟥 max_rss_usage [+853.188KB; +1043.670KB] or [+4.163%; +5.092%]

scenario:httppropagationextract-invalid_span_id_header

• 🟩 max_rss_usage [-1056.949KB; -648.216KB] or [-4.960%; -3.042%]

scenario:httppropagationextract-large_header_no_matches

• 🟥 max_rss_usage [+0.891MB; +1.298MB] or [+4.393%; +6.398%]

scenario:httppropagationextract-large_valid_headers_all

• 🟩 max_rss_usage [-948.203KB; -436.654KB] or [-4.489%; -2.067%]

scenario:httppropagationextract-medium_header_no_matches

• 🟥 max_rss_usage [+1.196MB; +1.354MB] or [+5.937%; +6.723%]

scenario:httppropagationextract-medium_valid_headers_all

• 🟩 max_rss_usage [-1070.577KB; -640.322KB] or [-5.021%; -3.003%]

scenario:httppropagationextract-none_propagation_style

• 🟩 max_rss_usage [-702.260KB; -510.156KB] or [-3.281%; -2.384%]

scenario:httppropagationextract-valid_headers_basic

• 🟥 max_rss_usage [+488.181KB; +727.921KB] or [+2.346%; +3.499%]

scenario:httppropagationextract-wsgi_invalid_priority_header

• 🟥 max_rss_usage [+714.160KB; +763.268KB] or [+3.446%; +3.683%]

scenario:httppropagationextract-wsgi_invalid_span_id_header

• 🟥 max_rss_usage [+0.862MB; +1.202MB] or [+4.252%; +5.928%]

scenario:httppropagationextract-wsgi_large_header_no_matches

• 🟥 max_rss_usage [+1.024MB; +1.130MB] or [+5.028%; +5.548%]

scenario:httppropagationextract-wsgi_large_valid_headers_all

• 🟩 max_rss_usage [-1063.778KB; -878.545KB] or [-4.980%; -4.113%]

scenario:httppropagationextract-wsgi_medium_header_no_matches

• 🟥 max_rss_usage [+782.482KB; +1066.862KB] or [+3.830%; +5.222%]

scenario:httppropagationextract-wsgi_medium_valid_headers_all

• 🟩 max_rss_usage [-1047.167KB; -821.838KB] or [-4.917%; -3.859%]

scenario:httppropagationinject-with_all

• 🟩 max_rss_usage [-710.549KB; -673.080KB] or [-3.320%; -3.145%]

scenario:httppropagationinject-with_tags

• 🟩 max_rss_usage [-625.448KB; -484.977KB] or [-2.928%; -2.270%]

scenario:httppropagationinject-with_tags_invalid

• 🟩 max_rss_usage [-696.000KB; -660.186KB] or [-3.256%; -3.088%]

scenario:otelspan-start-finish

• 🟥 max_rss_usage [+1.114MB; +1.170MB] or [+5.175%; +5.434%]

scenario:otelspan-start-finish-telemetry

• 🟩 max_rss_usage [-787.252KB; -705.330KB] or [-3.453%; -3.093%]

scenario:sethttpmeta-all-disabled

• 🟥 max_rss_usage [+609.337KB; +772.654KB] or [+2.894%; +3.669%]

scenario:sethttpmeta-all-enabled

• 🟥 max_rss_usage [+428.191KB; +699.438KB] or [+2.031%; +3.318%]

scenario:sethttpmeta-collectipvariant_exists

• 🟥 max_rss_usage [+689.833KB; +739.262KB] or [+3.279%; +3.514%]

scenario:sethttpmeta-obfuscation-send-querystring-disabled

• 🟥 max_rss_usage [+453.530KB; +723.251KB] or [+2.132%; +3.399%]

scenario:sethttpmeta-obfuscation-worst-case-explicit-query

• 🟥 max_rss_usage [+769.616KB; +992.893KB] or [+3.663%; +4.726%]

scenario:sethttpmeta-obfuscation-worst-case-implicit-query

• 🟥 max_rss_usage [+603.357KB; +756.924KB] or [+2.835%; +3.557%]

scenario:sethttpmeta-useragentvariant_exists_1

• 🟥 max_rss_usage [+667.176KB; +732.018KB] or [+3.168%; +3.476%]

scenario:sethttpmeta-useragentvariant_exists_2

• 🟩 max_rss_usage [-733.997KB; -684.038KB] or [-3.371%; -3.142%]

scenario:sethttpmeta-useragentvariant_exists_3

• 🟩 max_rss_usage [-717.730KB; -671.633KB] or [-3.299%; -3.087%]

scenario:sethttpmeta-useragentvariant_not_exists_1

• 🟥 max_rss_usage [+437.083KB; +694.233KB] or [+2.075%; +3.296%]

scenario:span-start-finish

• 🟩 max_rss_usage [-723.281KB; -670.588KB] or [-3.365%; -3.119%]

scenario:span-start-finish-telemetry

• 🟥 max_rss_usage [+1.007MB; +1.176MB] or [+4.919%; +5.743%]

scenario:span-start-finish-traceid128

• 🟥 max_rss_usage [+1.102MB; +1.154MB] or [+5.413%; +5.668%]

scenario:tracer-large

• 🟩 max_rss_usage [-1.098MB; -1.017MB] or [-4.852%; -4.491%]

scenario:tracer-small

• 🟩 max_rss_usage [-1.166MB; -1.084MB] or [-5.400%; -5.020%]