feat: added environment capability [APMSP-3780]

[Aaalibaba42]

What does this PR do?

Added capability to read and write environment variables

Motivation

dd-trace-js needing to add info from the env in their requests, it's better to have libdatadog drive the call

Additional Notes

Nop

How to test the change?

check, tests, check for wasm32

[datadog-official]

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 50.00%
• Overall Coverage: 74.61% (-0.14%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 5fedbee | Docs | Datadog PR Page | Give us feedback!}

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[dd-octo-sts]

Artifact Size Benchmark Report

aarch64-alpine-linux-musl

Artifact	Baseline	Commit	Change
/aarch64-alpine-linux-musl/lib/libdatadog_profiling.a	86.33 MB	86.33 MB	-0% (-832 B) 👌
/aarch64-alpine-linux-musl/lib/libdatadog_profiling.so	7.88 MB	7.88 MB	0% (0 B) 👌

aarch64-unknown-linux-gnu

Artifact	Baseline	Commit	Change
/aarch64-unknown-linux-gnu/lib/libdatadog_profiling.so	10.62 MB	10.62 MB	-0% (-136 B) 👌
/aarch64-unknown-linux-gnu/lib/libdatadog_profiling.a	97.54 MB	97.54 MB	-0% (-5.82 KB) 👌

libdatadog-x64-windows

Artifact	Baseline	Commit	Change
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.dll	25.58 MB	25.58 MB	0% (0 B) 👌
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.lib	89.18 KB	89.18 KB	0% (0 B) 👌
/libdatadog-x64-windows/debug/dynamic/datadog_profiling_ffi.pdb	185.48 MB	185.53 MB	+.02% (+56.00 KB) 🔍
/libdatadog-x64-windows/debug/static/datadog_profiling_ffi.lib	958.37 MB	958.59 MB	+.02% (+223.41 KB) 🔍
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.dll	8.37 MB	8.37 MB	0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.lib	89.18 KB	89.18 KB	0% (0 B) 👌
/libdatadog-x64-windows/release/dynamic/datadog_profiling_ffi.pdb	24.76 MB	24.76 MB	--.03% (-8.00 KB) 💪
/libdatadog-x64-windows/release/static/datadog_profiling_ffi.lib	49.28 MB	49.28 MB	-0% (-1.04 KB) 👌

libdatadog-x86-windows

Artifact	Baseline	Commit	Change
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.dll	22.23 MB	22.23 MB	+0% (+512 B) 👌
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.lib	90.58 KB	90.58 KB	0% (0 B) 👌
/libdatadog-x86-windows/debug/dynamic/datadog_profiling_ffi.pdb	189.95 MB	190.00 MB	+.02% (+48.00 KB) 🔍
/libdatadog-x86-windows/debug/static/datadog_profiling_ffi.lib	946.26 MB	946.53 MB	+.02% (+277.21 KB) 🔍
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.dll	6.47 MB	6.47 MB	--.01% (-1.00 KB) 💪
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.lib	90.58 KB	90.58 KB	0% (0 B) 👌
/libdatadog-x86-windows/release/dynamic/datadog_profiling_ffi.pdb	26.59 MB	26.58 MB	--.02% (-8.00 KB) 💪
/libdatadog-x86-windows/release/static/datadog_profiling_ffi.lib	46.90 MB	46.89 MB	--.02% (-10.39 KB) 💪

x86_64-alpine-linux-musl

Artifact	Baseline	Commit	Change
/x86_64-alpine-linux-musl/lib/libdatadog_profiling.a	77.08 MB	77.08 MB	+0% (+2.24 KB) 👌
/x86_64-alpine-linux-musl/lib/libdatadog_profiling.so	8.83 MB	8.83 MB	0% (0 B) 👌

x86_64-unknown-linux-gnu

Artifact	Baseline	Commit	Change
/x86_64-unknown-linux-gnu/lib/libdatadog_profiling.a	92.50 MB	92.50 MB	-0% (-2.63 KB) 👌
/x86_64-unknown-linux-gnu/lib/libdatadog_profiling.so	10.74 MB	10.74 MB	-0% (-168 B) 👌

[pr-commenter]

Benchmarks

Comparison

Benchmark execution time: 2026-07-16 16:39:34

Comparing candidate commit 5fedbee in PR branch jwiriath/env-caps with baseline commit 4a914bb in branch main.

Found 7 performance improvements and 14 performance regressions! Performance is the same for 121 metrics, 0 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:msgpack_decoder::v05/low_sharing/10000

• 🟩 execution_time [-1.038ms; -0.989ms] or [-5.617%; -5.354%]
• 🟩 throughput [+30746.129op/s; +32003.010op/s] or [+5.679%; +5.912%]

scenario:otlp/e2e_json/1x1000

• 🟥 execution_time [+401.876µs; +412.250µs] or [+9.840%; +10.094%]

scenario:otlp/encode_json/1x1000

• 🟥 execution_time [+420.010µs; +420.552µs] or [+23.810%; +23.841%]

scenario:otlp/encode_protobuf/1x1000

• 🟩 execution_time [-59.665µs; -58.766µs] or [-5.330%; -5.249%]

scenario:profiles_dictionary/profile_string_inserts/threads/1

• 🟥 execution_time [+15.249µs; +17.467µs] or [+4.977%; +5.701%]
• 🟥 throughput [-180508.596op/s; -158223.709op/s] or [-5.400%; -4.734%]

scenario:vec_map/get_hit/128

• 🟥 execution_time [+943.536ns; +951.197ns] or [+7.524%; +7.585%]
• 🟥 throughput [-719786.911op/s; -714153.232op/s] or [-7.052%; -6.996%]

scenario:vec_map/get_hit/16

• 🟩 execution_time [-12.525ns; -12.287ns] or [-5.871%; -5.759%]
• 🟩 throughput [+4586506.473op/s; +4671447.990op/s] or [+6.116%; +6.229%]

scenario:vec_map/get_hit/64

• 🟥 execution_time [+240.762ns; +243.893ns] or [+7.038%; +7.129%]
• 🟥 throughput [-1245072.553op/s; -1229635.785op/s] or [-6.656%; -6.573%]

scenario:vec_map/get_hit/8

• 🟩 execution_time [-7.846ns; -7.689ns] or [-12.709%; -12.456%]
• 🟩 throughput [+18476983.580op/s; +18812574.513op/s] or [+14.257%; +14.516%]

scenario:vec_map/get_mut/128

• 🟥 execution_time [+2.397µs; +2.503µs] or [+17.478%; +18.251%]
• 🟥 throughput [-1444988.920op/s; -1382418.623op/s] or [-15.476%; -14.806%]

scenario:vec_map/get_mut/16

• 🟥 execution_time [+28.786ns; +38.602ns] or [+10.742%; +14.406%]
• 🟥 throughput [-7889452.435op/s; -5791080.412op/s] or [-13.092%; -9.610%]

scenario:vec_map/get_mut/64

• 🟥 execution_time [+537.574ns; +575.132ns] or [+14.156%; +15.145%]
• 🟥 throughput [-2236502.585op/s; -2083164.625op/s] or [-13.260%; -12.351%]

Benchmark execution time: 2026-07-16 16:55:13

Comparing candidate commit 5fedbee in PR branch jwiriath/env-caps with baseline commit 4a914bb in branch main.

Found 4 performance improvements and 24 performance regressions! Performance is the same for 149 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:alloc_free/sampled_system_fast_path/4096

• 🟩 execution_time [-10.987ns; -10.866ns] or [-10.795%; -10.676%]

scenario:alloc_free/system/4096

• 🟩 execution_time [-12.060ns; -11.890ns] or [-11.254%; -11.095%]

scenario:credit_card/is_card_number/ 3782-8224-6310-005

• 🟥 execution_time [+5.561µs; +5.734µs] or [+7.403%; +7.634%]
• 🟥 throughput [-946635.763op/s; -916665.085op/s] or [-7.110%; -6.885%]

scenario:credit_card/is_card_number/ 378282246310005

• 🟥 execution_time [+5.878µs; +5.961µs] or [+8.672%; +8.795%]
• 🟥 throughput [-1192586.414op/s; -1177089.173op/s] or [-8.083%; -7.978%]

scenario:credit_card/is_card_number/378282246310005

• 🟥 execution_time [+6.158µs; +6.236µs] or [+9.538%; +9.659%]
• 🟥 throughput [-1364287.384op/s; -1348486.299op/s] or [-8.808%; -8.706%]

scenario:credit_card/is_card_number/37828224631000521389798

• 🟥 execution_time [+7.920µs; +7.970µs] or [+17.500%; +17.611%]
• 🟥 throughput [-3312107.642op/s; -3288028.384op/s] or [-14.989%; -14.880%]

scenario:credit_card/is_card_number/x371413321323331

• 🟥 execution_time [+405.142ns; +408.656ns] or [+6.704%; +6.762%]
• 🟥 throughput [-10484379.218op/s; -10392941.857op/s] or [-6.336%; -6.281%]

scenario:credit_card/is_card_number_no_luhn/ 378282246310005

• 🟥 execution_time [+5.371µs; +5.409µs] or [+10.120%; +10.191%]
• 🟥 throughput [-1742433.785op/s; -1731028.681op/s] or [-9.249%; -9.188%]

scenario:credit_card/is_card_number_no_luhn/378282246310005

• 🟥 execution_time [+5.703µs; +5.752µs] or [+11.436%; +11.536%]
• 🟥 throughput [-2074083.819op/s; -2057724.127op/s] or [-10.343%; -10.261%]

scenario:credit_card/is_card_number_no_luhn/37828224631000521389798

• 🟥 execution_time [+7.844µs; +7.902µs] or [+17.332%; +17.460%]
• 🟥 throughput [-3287163.891op/s; -3261518.109op/s] or [-14.877%; -14.761%]

scenario:credit_card/is_card_number_no_luhn/x371413321323331

• 🟥 execution_time [+404.721ns; +407.985ns] or [+6.697%; +6.751%]
• 🟥 throughput [-10468488.756op/s; -10384658.252op/s] or [-6.326%; -6.275%]

scenario:glob_matcher/ascii_case_insensitive_match/wall_time

• 🟥 execution_time [+1.990ns; +2.017ns] or [+7.285%; +7.384%]

scenario:glob_matcher/ascii_exact_miss/wall_time

• 🟥 execution_time [+1.172ns; +1.211ns] or [+9.400%; +9.713%]

scenario:glob_matcher/ascii_wildcard_backtrack_match/wall_time

• 🟥 execution_time [+3.273ns; +3.289ns] or [+8.868%; +8.911%]

scenario:glob_matcher/ascii_wildcard_question_match/wall_time

• 🟥 execution_time [+1.914ns; +1.935ns] or [+5.196%; +5.250%]

scenario:trace_buffer/4_senders/no_delay

• 🟥 execution_time [+159.827µs; +193.603µs] or [+6.960%; +8.431%]
• 🟥 throughput [-123694.606op/s; -101635.464op/s] or [-7.878%; -6.473%]

scenario:trace_buffer/8_senders/no_delay

• 🟩 execution_time [-371.957µs; -315.307µs] or [-5.631%; -4.774%]
• 🟩 throughput [+55344.417op/s; +65903.252op/s] or [+5.076%; +6.045%]

Candidate

Omitted due to size.

Baseline

Omitted due to size.

[Aaalibaba42]

@codex review

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: bed4965e07

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[yannham]

Besides the original motivation, I'm all for env capability: I think it's a step in the right direction to get rid of the get/set race conditions that have popped up in the past. Once everything uses the capability, we can silently switch to a different implementation - one that snapshots the environment at the beginning for example - which is much less prone to races.

However, I would remove set and unset from the API if they are not needed, or even would make them a compile time error. As mentioned in the Rust documentation and discussed extensively elsewhere, they're just impossible to get right in a multi-threaded environment, even within a pure Rust program, and I think we should just not use it. It's worse in libdatadog context, where we might interact with C and multiple other runtimes.

[Aaalibaba42]

Agreed after discussion that adding them to the full API like that is at least prematured, especially since we don't need it in JS either for now. Fundamentally I think it could be okay to have these methods solely in the JS side since the process should be single threaded etc, but the shape and way that ought to be done should not be part of this PR and should require discussions. The idea of having the capability for the environment snapshotting the starting environment and simulating the rest and being the single source of truth for it to work even in multithreaded things is interesting o/

[yannham]

Should we mention why we don't include set_var in the trait's documentation?

[Aaalibaba42]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-07-16 16:06:50 UTC ℹ️ Start processing command /merge

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2026-07-16 17:02:11 UTC ℹ️ MergeQueue: merge request added to the queue

The expected merge time in main is approximately 1h (p90).

---

2026-07-16 17:43:10 UTC ℹ️ MergeQueue: This merge request was merged