chore(http_server): emit pre-request web event

[litianningdatadog]

Stacked PRs:

• chore(runtime): add explicit identity refresh #19778
  • chore(flask): emit MicroVM request-starting event #19816
    • 👉🏽 This PR chore(http_server): emit pre-request web event #19817
    • feat(aws-lambda-microvm): refresh identity on Flask run hook #19825
    • chore(remoteconfig): refresh client identity on runtime refresh #19818
      • chore(appsec): tag spans with refreshed rc client id #19819
    • chore(tracer): tracer/writer identity refresh and stale-buffer reset #19820
    • fix(telemetry): rebuild worker on identity refresh #19821
    • chore(runtime): refresh runtime metric identity and collector state #19822
    • chore(crashtracking): reconfigure after identity refresh #19823
    • chore(symbol-db): refresh metadata after identity refresh #19824

Description

Follow-up to #19816. Adds a stdlib http_server integration for raw http.server handlers that need to emit WEB_REQUEST_STARTING before request handling continues.

The integration wraps http.server.BaseHTTPRequestHandler.parse_request and dispatches the event with (method, path) after the request line parses successfully. It does not create spans. It is automatically enabled only in AWS Lambda MicroVM environments, can be force-enabled with DD_TRACE_HTTP_SERVER_ENABLED=true, and can be disabled with DD_TRACE_HTTP_SERVER_ENABLED=false; it intentionally has no service-name config.

This PR also adds the integration metadata needed for auto-patching, docs discovery, suite selection, and supported-configuration validation. The .riot/requirements/*.txt files are generated locks for the new http_server Riot env across the Python versions selected by select_pys(). The supported-configuration checker now allows no-span integrations to skip DD_{NAME}_SERVICE[_NAME] entries.

This replaces #19799 after renaming the branch from tianning.li/3-http-server-request-starting-event to tianning.li/2-1-http-server-request-starting-event.

Testing

• scripts/lint fmt ddtrace/_monkey.py ddtrace/contrib/internal/http_server/__init__.py ddtrace/contrib/internal/http_server/patch.py ddtrace/internal/settings/_supported_configurations.py riotfile.py scripts/supported_configurations.py tests/contrib/http_server/__init__.py tests/contrib/http_server/test_http_server_patch.py tests/contrib/http_server/test_microvm_identity_refresh.py
• scripts/lint style ddtrace/_monkey.py ddtrace/contrib/internal/http_server/__init__.py ddtrace/contrib/internal/http_server/patch.py ddtrace/internal/settings/_supported_configurations.py riotfile.py scripts/supported_configurations.py tests/contrib/http_server/__init__.py tests/contrib/http_server/test_http_server_patch.py tests/contrib/http_server/test_microvm_identity_refresh.py
• scripts/lint supported-config-check
• scripts/run-tests --venv 13ed954 tests/contrib/http_server

Release note

No Reno fragment. This is internal runtime-identity plumbing for a no-span integration and does not change trace output by itself. Use changelog/no-changelog.

Additional Notes

Depends on #19816 and #19778.

[datadog-datadog-prod-us1]

 

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⚠️ Warnings

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ℹ️ Info

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🧪 All tests passed
❄️ No new flaky tests detected

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[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 55febfa654

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[cit-pr-commenter-54b7da]

Codeowners resolved as

Resolved from the full PR diff against tianning.li/2-flask-web-request-starting-event using the target branch CODEOWNERS file.
CODEOWNERS team requests not listed below are not required by the current file set.

.riot/requirements/1362718.txt                                          @DataDog/apm-python
.riot/requirements/13ed954.txt                                          @DataDog/apm-python
.riot/requirements/1638d0f.txt                                          @DataDog/apm-python
.riot/requirements/180047f.txt                                          @DataDog/apm-python
.riot/requirements/3cb8c3c.txt                                          @DataDog/apm-python
.riot/requirements/43423a3.txt                                          @DataDog/apm-python
ddtrace/_monkey.py                                                      @DataDog/apm-core-python @DataDog/apm-idm-python
ddtrace/contrib/internal/http_server/__init__.py                        @DataDog/apm-core-python @DataDog/apm-idm-python
ddtrace/contrib/internal/http_server/patch.py                           @DataDog/apm-core-python @DataDog/apm-idm-python
ddtrace/internal/settings/_config.py                                    @DataDog/python-guild @DataDog/apm-sdk-capabilities-python
ddtrace/internal/settings/_supported_configurations.py                  @DataDog/apm-python
docs/index.rst                                                          @DataDog/python-guild
docs/integrations.rst                                                   @DataDog/python-guild
riotfile.py                                                             @DataDog/apm-python
scripts/integration_registry/registry.yaml                              @DataDog/apm-idm-python
scripts/supported_configurations.py                                     @DataDog/apm-sdk-capabilities-python
supported-configurations.json                                           @DataDog/apm-python
tests/contrib/http_server/__init__.py                                   @DataDog/apm-core-python @DataDog/apm-idm-python
tests/contrib/http_server/test_http_server_patch.py                     @DataDog/apm-core-python @DataDog/apm-idm-python
tests/contrib/http_server/test_microvm_identity_refresh.py              @DataDog/apm-core-python @DataDog/apm-idm-python
tests/contrib/suitespec.yml                                             @DataDog/python-guild
tests/tracer/test_monkey.py                                             @DataDog/apm-sdk-capabilities-python

[cit-pr-commenter-54b7da]

Circular import analysis

⚠️ Existing circular imports

There are 3 circular imports that already exist on the base branch and have not been changed by this PR.

ddtrace.llmobs -> ddtrace.llmobs._evaluators -> ddtrace.llmobs._evaluators.format -> ddtrace.llmobs._experiment -> ddtrace.llmobs
ddtrace.errortracking._handled_exceptions.bytecode_injector -> ddtrace.errortracking._handled_exceptions.callbacks -> ddtrace.errortracking._handled_exceptions.collector -> ddtrace.errortracking._handled_exceptions.bytecode_reporting -> ddtrace.errortracking._handled_exceptions.bytecode_injector
ddtrace.appsec._asm_request_context -> ddtrace.appsec._iast._iast_request_context_base -> ddtrace.appsec._iast._iast_env -> ddtrace.appsec._iast.reporter -> ddtrace.appsec._exploit_prevention.stack_traces -> ddtrace.appsec._asm_request_context

[cit-pr-commenter-54b7da]

Dependency direction analysis

⚠️ Existing dependency direction violations

There are 250 dependency direction violations that already exist on the base branch and have not been changed by this PR.

Show existing violations (showing 5 of 250 highest severity)

ddtrace.internal.tracemethods -×-> ddtrace.trace  (internal-core -> product:tracing, score=135)
ddtrace.internal.opentelemetry.trace -×-> ddtrace.trace  (product:opentelemetry -> product:tracing, score=133)
ddtrace.internal.opentelemetry.span -×-> ddtrace.trace  (product:opentelemetry -> product:tracing, score=133)
ddtrace.debugging._signal.model -×-> ddtrace.trace  (product:debugging -> product:tracing, score=133)
ddtrace.profiling.collector.stack -×-> ddtrace.trace  (product:profiling -> product:tracing, score=133)

To see all violations, download the layers-base.json and layers-pr.json artifacts from this CI job and run:

uv run --script scripts/import-analysis/layers.py compare layers-base.json layers-pr.json

[pr-commenter]

Benchmarks

Benchmark execution time: 2026-08-25 04:07:49

Comparing candidate commit a2cffdc in PR branch tianning.li/2-1-http-server-request-starting-event with baseline commit a0e3c42 in branch tianning.li/2-flask-web-request-starting-event.

📊 Benchmarking dashboard

Found 0 performance improvements and 10 performance regressions! Performance is the same for 612 metrics, 10 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

• 🟩 = significantly better candidate vs. baseline
• 🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

scenario:httppropagationinject-ids_only

• 🟥 execution_time [+2.018µs; +2.189µs] or [+10.518%; +11.409%]

scenario:iastaspects-add_aspect

• 🟥 execution_time [+13.679µs; +17.989µs] or [+13.423%; +17.653%]

scenario:iastaspects-join_aspect

• 🟥 execution_time [+46.397µs; +50.189µs] or [+22.018%; +23.817%]

scenario:iastaspects-ljust_noaspect

• 🟥 execution_time [+58.326µs; +63.757µs] or [+20.531%; +22.443%]

scenario:iastaspects-title_aspect

• 🟥 execution_time [+58.710µs; +67.462µs] or [+21.347%; +24.529%]

scenario:iastaspectsospath-ospathbasename_aspect

• 🟥 execution_time [+139.894µs; +147.478µs] or [+34.039%; +35.885%]

scenario:iastaspectssplit-rsplit_aspect

• 🟥 execution_time [+16.841µs; +20.460µs] or [+11.712%; +14.228%]

scenario:span-start

• 🟥 execution_time [+1.331ms; +1.495ms] or [+8.743%; +9.820%]

scenario:telemetryaddmetric-1-count-metric-1-times

• 🟥 execution_time [+406.923ns; +450.182ns] or [+14.864%; +16.444%]

scenario:tracer-small

• 🟥 execution_time [+27.718µs; +30.273µs] or [+8.206%; +8.962%]

Unstable benchmarks

These benchmarks have a confidence interval too wide to call a change; treat them as noise rather than signal.

scenario:coreapiscenario-context_with_data_listeners

• unstable execution_time [-748.964ns; +732.356ns] or [-6.789%; +6.638%]

scenario:coreapiscenario-core_dispatch_1_listener

• unstable execution_time [-37.643ns; +28.503ns] or [-6.140%; +4.649%]

scenario:coreapiscenario-core_dispatch_50_listeners

• unstable execution_time [-1780.816ns; +1555.894ns] or [-10.350%; +9.043%]

scenario:coreapiscenario-core_dispatch_exception_listeners

• unstable execution_time [-1248.967ns; +1218.121ns] or [-9.658%; +9.419%]

scenario:coreapiscenario-core_dispatch_listeners

• unstable execution_time [-345.121ns; +312.996ns] or [-9.324%; +8.456%]

scenario:coreapiscenario-core_dispatch_no_args_listeners

• unstable execution_time [-282.204ns; +226.823ns] or [-9.626%; +7.737%]

scenario:coreapiscenario-core_dispatch_with_results_1_listener

• unstable execution_time [-89.121ns; +57.630ns] or [-7.747%; +5.010%]

scenario:coreapiscenario-core_dispatch_with_results_50_listeners

• unstable execution_time [-3705.609ns; +4280.949ns] or [-9.206%; +10.636%]

scenario:coreapiscenario-core_dispatch_with_results_listeners

• unstable execution_time [-738.106ns; +802.110ns] or [-9.259%; +10.062%]

scenario:packagesupdateimporteddependencies-import_many_stdlib_cached

• unstable execution_time [-60336.977ns; +60329.065ns] or [-9.439%; +9.438%]

[chatgpt-codex-connector]

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Reviewed commit: 38761fa550

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[chatgpt-codex-connector]

Reuse the MicroVM predicate for the patch default

When AWS_LAMBDA_MICROVM_IMAGE_ARN contains only whitespace, in_aws_lambda_microvm() deliberately returns false after stripping the value, but this expression evaluates to true. In that environment _patch_all() therefore installs and reports the integration as automatically enabled even though its wrapper suppresses every event, adding an unnecessary check to every http.server request and contradicting the documented MicroVM-only default; derive this value using the same stripped predicate.

AGENTS.md reference: AGENTS.md:L16-L16

Useful? React with 👍 / 👎.

[brettlangdon]

do we actually need this? are any customers asking for an http.server integration? is there any MicroVM setup that just uses http.server directly?

after about 10 years, this is the first I've seen it suggested as an integration.

[litianningdatadog]

close it as it is out of the scope