feat(openfeature): emit server-side EVP flagevaluation#3984
feat(openfeature): emit server-side EVP flagevaluation#3984leoromanovsky wants to merge 18 commits into
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…ith PREP-01 libdatadog - Enable 'flagevaluation-evp' feature on datadog-ffe dep (FfeFlagEvaluationBatch type now compiled) - Fix components-rs/bytes.rs: update 4x VecMap::remove() -> remove_slow() for libdatadog compat post-commit 74284cac7 (VecMap API renamed); this unblocks compilation against the PREP-01 libdatadog ref
…patch - Two-tier aggregation in components-rs/ffe.rs: full→degraded→drop-counted with caps GLOBAL_CAP=131072/PER_FLAG_CAP=10000/DEGRADED_CAP=32768 - Killswitch DD_FLAGGING_EVALUATION_COUNTS_ENABLED (default: on) via evp_enabled() in Rust and isEvpEnabled() in EvaluationMetricRecorder.php - ddog_ffe_flush_flag_evaluation_batch() Rust C-export dispatches SidecarAction::FfeFlagEvaluationBatch via sidecar_blocking::enqueue_actions - ddtrace_ffe_flush_flag_evaluation_batch() C wrapper in tracer/ffe.c mirrors existing exposure/metric flush pattern with sidecar globals - RSHUTDOWN call added in tracer/ddtrace.c after existing flush calls - 11 Rust unit tests covering both tiers, overflow, drain, killswitch
…EVP aggregator race ddog_ffe_evaluate() records into the global EVP_AGGREGATOR; without EVP_TEST_LOCK the test ran concurrently with degraded_tier_overflow tests, causing dropped_degraded_overflow to be 2 instead of 1.
… + regen Cargo.lock Points dd-trace-php's libdatadog submodule at the local PREP-01 commit containing the flagevaluation EVP emitter (FfeFlagEvaluationBatch), so components-rs builds against it via the datadog-ffe path dep with the flagevaluation-evp feature. NOTE: 89a2ba7fc is local/unpushed — re-point to the merged upstream libdatadog SHA before any PR.
The Rust C-export ddog_ffe_flush_flag_evaluation_batch (components-rs/ffe.rs) was added without a matching prototype in the committed cbindgen header components-rs/datadog.h. tracer/ffe.c calls it, so PHP8's stricter toolchain fails with -Werror=implicit-function-declaration (ddtrace.so link Error 2). PHP7 only warned and linked, masking the bug. Prototype matches the Rust signature (SidecarTransport**/InstanceId*/QueueId*/CharSlice x3).
…ow drops The full-tier EVP flagevaluation drain previously emitted context: None and drained the degraded-overflow drop count silently. - Full tier now carries the pruned evaluation context (shared prune_context bounds: <=256 fields, string values >256 bytes skipped) plus context.dd.service, matching the degraded tier's cap enforcement. The pruned context is captured once per bucket at insertion and carried verbatim into the drained event. - The degraded-tier overflow drop counter is read-and-reset at drain and logged via tracing::warn when non-zero, so an undersized degradedCap is observable instead of a silent loss of legitimate counts.
…low surfacing - ddog_ffe_evaluate_populates_evp_aggregator_for_flush / _respects_killswitch: drive the real FFI entry point ddog_ffe_evaluate (the function the PHP/C layer calls) and assert it feeds the aggregator that the sidecar flush drains, closing the 'unit-green but emits nothing' gap that earlier tests left uncovered. - full_tier_event_carries_pruned_context / _prunes_oversized_string_values / _empty_context_emits_no_context_object: assert the full tier carries the pruned context and enforces the field/value bounds. - drain_resets_degraded_overflow_drop_counter: assert drain reads-and-resets the observable overflow drop counter.
…ncode-safe wire + reliable enqueue) Bump the libdatadog submodule to the bincode-safe flagevaluation fix (DataDog/libdatadog#2117): the worker->sidecar IPC is bincode, which the old serde_json::Value + skip_serializing_if wire types could not deserialize, so the sidecar silently dropped every batch. - Stringify the pruned full-tier context (JSON object string) at drain so the bincode wire stays plain; the sidecar flusher re-expands it into a JSON object for the POST. - Use sidecar_blocking::enqueue_actions_reliable for the one-shot RSHUTDOWN flush.
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…2446-evp-flagevaluation-php # Conflicts: # libdatadog
Benchmarks [ tracer ]Benchmark execution time: 2026-06-17 08:16:43 Comparing candidate commit 696c397 in PR branch Some scenarios are present only in baseline or only in candidate runs. If you didn't create or remove some scenarios in your branch, this maybe a sign of crashed benchmarks 💥💥💥 Scenarios present only in candidate:
Found 2 performance improvements and 0 performance regressions! Performance is the same for 192 metrics, 0 unstable metrics.
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Motivation
PHP server-side flag evaluations need to emit aggregated EVP
flagevaluationpayloads through the native Rust/C and libdatadog sidecar path, while preserving the existing OTel metric and exposure paths. The emitted events must match the live flageval-worker contract: schema-visible aggregation dimensions only, no OpenFeaturereason, bounded context before buffering, andtargeting_rule.keyonly when real targeting-rule metadata exists.Changes
reasonout of EVP payloads and aggregation keys.libdatadogto53f81e56510f9981dd7db95a9dc7dec592cb9678, which adds sidecar degraded coalescing and bounded EVP POST chunks.Decisions
reasonis not a hidden aggregate key.Validation Evidence
Validated on 2026-06-17 with PHP SDK commit
696c397f3ad7fd9b8b2135e16c9424c49a55da1f, libdatadog commit53f81e56510f9981dd7db95a9dc7dec592cb9678, and system-tests PHP enable commita29bfcfa1b2fa172adfee5f61a2a3424456763aebased on #7146 commit2e7ad616bc525ee76698f34a686da549701b1914.cargo test -p datadog-sidecar ffe_flagevaluation_flusher --libfromdd-trace-php/libdatadog- PASS, 14 passed.cargo +nightly test -p datadog-php ffe:: --libfromdd-trace-php- PASS, 21 passed.docker run --rm -w /var/app -v "$PWD":/var/app datadog/dd-trace-ci:php-8.2_centos-7 bash -lc 'export CARGO_HOME=$PWD/tmp/cargo_home; make -j$(nproc)'- PASS../build.sh php -w apache-mod-8.2fromsystem-tests-php- PASS../run.sh FEATURE_FLAGGING_AND_EXPERIMENTATION --library php --weblog apache-mod-8.2 -k "Flagevaluation_Degradation"- PASS, 1 passed, 2584 deselected in 34.38s../run.sh FEATURE_FLAGGING_AND_EXPERIMENTATION --library php --weblog apache-mod-8.2 -k "test_flag_eval_evp"- PASS, 8 passed, 2577 deselected in 63.53s.events=10001,total=10050,full_total=10000,degraded_count=1,degraded_total=50.php@1.21.0; weblogapache-mod-8.2; local PHP 8.2 aarch64ddtrace.soinstalled through the system-tests/binaries/ddtrace.sooverride.