fix(id): reset agentless exporter identity state

[litianningdatadog]

What does this PR do?

Reset trace exporter state when an AWS Lambda MicroVM refreshes its identity. A snapshot can contain buffered spans or an in-flight delivery; restoring that snapshot must not resend the old payload under the clone's new runtime identity.

This PR is the second step in the stacked breakdown of PR #9814, tracked by SVLS-9768.

Changes

• Subscribe both the regular agent exporter and the agentless exporter to datadog:identity:refresh.
• Clear each exporter's pending flush timer on refresh.
• Reset the pending agent batch and shared request state for the regular agent exporter.
• Close the private libdatadog pipeline used by the agentless writer before resetting its encoder and shared request state.
• Add coverage for refresh handling, timer cleanup, and an active agentless pipeline.

Agentless exporter lifecycle

A refresh closes the current private libdatadog exporter; it does not create a replacement during the reset. The writer clears its cached exporter and configuration fields, then clears the encoded batch.

The next post-refresh flush that has data calls AgentlessWriter._sendPayload(). Its configuration check sees that no pipeline exporter exists and creates one with the current runtime ID, environment, API key, and endpoint. An empty flush does not recreate the exporter.

Dependency tree

• origin/master
  • #10338 01-common-exporter-agent-spanstats-reset-and-cancel
    • #10342 02-agentless-exporter-identity ← current PR
    • #10341 06-datastream-reset-and-cancel
  • #10339 03-dogstatsd-buffer-reset
  • #10340 04-otel-runtime-baseline
    • #10343 05-otel-runtime-metric-resets

This PR is part of the stacked review sequence above.

[dd-octo-sts]

Overall package size

Self size: 8.97 MB
Deduped: 9.7 MB
No deduping: 9.7 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | import-in-the-middle | 3.5.1 | 127.66 kB | 513.61 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | dc-polyfill | 0.1.11 | 25.74 kB | 25.74 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.29%. Comparing base (dda557a) to head (9ce96e0).

❗ There is a different number of reports uploaded between BASE (dda557a) and HEAD (9ce96e0). Click for more details.

HEAD has 14 uploads less than BASE

Flag	BASE (dda557a)	HEAD (9ce96e0)
master-coverage	12	0
llmobs	1	0
test-optimization	1	0

Additional details and impacted files

@@                                                    Coverage Diff                                                    @@
##           tianning.li/microvm-buffer-reset-01-common-exporter-agent-spanstats-reset-and-cancel   #10342       +/-   ##
=========================================================================================================================
- Coverage                                                                                 98.74%   81.29%   -17.46%     
=========================================================================================================================
  Files                                                                                      1029     1006       -23     
  Lines                                                                                    161396   154901     -6495     
  Branches                                                                                     74       74               
=========================================================================================================================
- Hits                                                                                     159374   125927    -33447     
- Misses                                                                                     2022    28974    +26952     

Flag	Coverage Δ
ai-guard	65.27% <61.90%> (+0.24%)	⬆️
apm-capabilities	63.75% <100.00%> (+0.22%)	⬆️
apm-integrations	81.54% <61.90%> (-0.26%)	⬇️
appsec	58.95% <61.90%> (+0.28%)	⬆️
debugger	70.18% <61.90%> (-0.08%)	⬇️
instrumentation	54.47% <61.90%> (+0.18%)	⬆️
llmobs	?
master-coverage	?
openfeature	66.50% <61.90%> (+0.08%)	⬆️
platform	69.37% <59.25%> (+0.05%)	⬆️
profiling	66.84% <61.90%> (-0.07%)	⬇️
serverless	66.00% <61.90%> (+0.36%)	⬆️
test-optimization	?

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-18T21:08:00.630635Z	9ce96e0	New commits
🔒 Security Review	✅ Completed 2026-09-18T21:09:51.366818Z	9ce96e0	New commits

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

[Copilot]

🔵 Needs a closer look

This is a draft, stacked identity-refresh change requiring final human review.

Pull request overview

Resets agent and agentless exporter state during MicroVM identity refreshes to prevent stale buffered data.

Changes:

• Adds identity-refresh handling for both exporters.
• Resets pending writer batches.
• Adds focused refresh tests.

File summaries

File	Summary
packages/dd-trace/test/exporters/agentless/exporter.spec.js	Tests agentless exporter refresh handling.
packages/dd-trace/test/exporters/agent/exporter.spec.js	Tests agent exporter refresh handling.
packages/dd-trace/src/exporters/agentless/index.js	Resets agentless writer state on identity refresh.
packages/dd-trace/src/exporters/agent/index.js	Resets agent writer state on identity refresh; separates the dc-polyfill third-party import group.

Review details

Suppressed comments (1)

packages/dd-trace/src/exporters/agent/index.js:4

• Please keep the new dc-polyfill dependency in its own third-party import group, separated from the Node core and internal imports. The neighboring exporter/common/writer.js:3-9 and this file's agentless counterpart use that grouping, and the current placement makes the import ordering inconsistent with the repository convention.

const { channel } = require('dc-polyfill')

• Files reviewed: 4/4 changed files
• Comments generated: 0
• Review effort level: Lite

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: b44ea439dc

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

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[datadog-datadog-prod-us1-2]

The agentless exporter keeps an active libdatadog request or retry after identity refresh. A restored MicroVM clone can send the old payload again.

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[datadog-datadog-prod-us1-2]

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 81.27% (-16.96%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 9ce96e0 | Docs | View more details | Give us feedback!}

[pr-commenter]

Benchmarks

Benchmark execution time: 2026-09-18 21:18:17

Comparing candidate commit 9ce96e0 in PR branch tianning.li/microvm-buffer-reset-02-agentless-exporter-identity with baseline commit dda557a in branch tianning.li/microvm-buffer-reset-01-common-exporter-agent-spanstats-reset-and-cancel.

📊 Benchmarking dashboard

Found 0 performance improvements and 0 performance regressions! Performance is the same for 2303 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 ----------------------------------'

Unstable benchmarks

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

scenario:appsec-iast-no-vulnerability-iast-enabled-default-config-20

• unstable max_rss_usage [-9.576MB; +13.558MB] or [-4.338%; +6.142%]

scenario:appsec-iast-with-vulnerability-iast-enabled-default-config-20

• unstable max_rss_usage [-29.628MB; +11.520MB] or [-8.488%; +3.301%]

scenario:encoders-0.4-immediate-flush-20

• unstable max_rss_usage [-4.890MB; +12.664MB] or [-6.494%; +16.819%]

scenario:llmobs-encode-unicode-mixed-20

• unstable max_rss_usage [-9256.262KB; +9193.862KB] or [-12.655%; +12.570%]

scenario:plugin-claude-agent-sdk-compact-stream-scan-26

• unstable execution_time [-281.139ms; +460.619ms] or [-3.940%; +6.455%]

scenario:plugin-graphql-long-with-depth-off-26

• unstable cpu_user_time [-405.771ms; +385.040ms] or [-5.437%; +5.159%]
• unstable execution_time [-430.870ms; +401.460ms] or [-5.666%; +5.279%]
• unstable max_rss_usage [-33.170MB; +26.418MB] or [-15.102%; +12.028%]
• unstable throughput [-17.699op/s; +19.407op/s] or [-5.230%; +5.735%]

scenario:plugin-memcached-hashring-24

• unstable execution_time [-73.273ms; +186.622ms] or [-2.877%; +7.328%]

[datadog-datadog-prod-us1-2]

More details

The child finding refers to telemetry retry logic that this PR does not change. It does not meet the changed-line rule.

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