[FFL-1273] bindings for ffe in openfeature provider by sameerank · Pull Request #5007 · DataDog/dd-trace-rb

sameerank · 2025-10-29T15:05:58Z

What does this PR do?

Motivation:

Change log entry

Additional Notes:

How to test the change?

github-actions · 2025-10-29T15:06:47Z

👋 Hey @DataDog/ruby-guild, please fill "Change log entry" section in the pull request description.

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**Change log entry**

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^{Visited at: 2025-11-07 01:16:03 UTC}

ext/libdatadog_api/extconf.rb

ivoanjo · 2025-10-30T16:53:17Z

setup_ffe.sh

+# profiling.h - minimal stub  
+cat > my-libdatadog-build/arm64-darwin-24/include/datadog/profiling.h << 'EOF'
+#ifndef DDOG_PROFILING_H
+#define DDOG_PROFILING_H
+
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include "common.h"
+
+// Minimal declarations for profiling functionality
+// Ruby bindings don't need full profiling API, just enough to link
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+// Stub function declarations - can be extended as needed
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif  // __cplusplus
+
+#endif  /* DDOG_PROFILING_H */
+EOF


Tip: You don't actually need to build profiling -- DD_PROFILING_NO_EXTENSION=true skips trying it to build at all.

Incorporated this into the script though I'm not sure that I'm using it right.

Most of the profiling dependencies are in ext/datadog_profiling_native_extension which I'm understand that env variable lets us skip, but there's still one profiling dependency in ext/libdatadog_api

dd-trace-rb/ext/libdatadog_api/datadog_ruby_common.h

Line 8 in f10f1df

#include <datadog/profiling.h>

So I still ended up needing to generate the profiling.h file

Aaah oops that's actually an oversight from when datadog_ruby_common.h was extracted out of profiling: this can be replaced with #include <datadog/common.h>. I'll open a PR to fix this

setup_ffe.sh

sameerank · 2025-10-30T22:40:58Z

setup_ffe.sh

To be deleted after libdatadog is published with datadog-ffe-ffi, at which point we no longer need to build and install it locally

ivoanjo · 2025-11-03T09:09:30Z

ext/libdatadog_api/feature_flags.c

+  Check_Type(targeting_key, T_STRING);
+  Check_Type(attributes_hash, T_HASH);


Minor: I recommend using our own ENFORCE_TYPE instead of Check_Type -- they behave similarly, but ENFORCE_TYPE gets you a much better error exception message (you can easily see it working, by e.g. on purpose switching to a wrong type here and seeing the error you get)

ivoanjo · 2025-11-03T09:11:05Z

lib/datadog/open_feature/binding.rb

+          unless Binding.supported?
+            raise(ArgumentError, "Feature Flags are not supported: #{Datadog::Core::LIBDATADOG_API_FAILURE}")
+          end


Since this gets repeated a lot, consider perhaps extracting it? (E.g. into a Binding.ensure_supported! or something like that?)

ivoanjo · 2025-11-03T09:28:01Z

I've opened #5018 with some small fixes as I mentioned in the comments.

pr-commenter · 2025-11-07T01:36:26Z

Benchmarks

Benchmark execution time: 2025-11-07 01:35:59

Comparing candidate commit 81c3973 in PR branch sameerank/FFL-1273-Bindings-for-ffe-in-openfeature-provider with baseline commit 81c3973 in branch FFL-1361-Evaluation-in-binding-in-ruby.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 44 metrics, 2 unstable metrics.

dd-oleksii · 2025-11-07T09:29:22Z

ext/libdatadog_api/feature_flags.c

+static VALUE configuration_alloc(VALUE klass) {
+  ddog_ffe_Handle_Configuration *config = ruby_xcalloc(1, sizeof(ddog_ffe_Handle_Configuration));
+  *config = NULL; // Initialize the handle to NULL
+  return TypedData_Wrap_Struct(klass, &configuration_typed_data, config);
+}
+
+static void configuration_free(void *ptr) {
+  ddog_ffe_Handle_Configuration *config = (ddog_ffe_Handle_Configuration *) ptr;
+  if (config && *config) {
+    ddog_ffe_configuration_drop(config);
+  }
+  ruby_xfree(ptr);
+}


nit: not entirely sure about this but handle is a pointer and it fits to data field (void *), so I think we can avoid allocations here, call rb_undef_alloc_func(configuration_class), and call TypedData_Wrap_Struct in configuration_initialize.

Suggested change

static VALUE configuration_alloc(VALUE klass) {

ddog_ffe_Handle_Configuration *config = ruby_xcalloc(1, sizeof(ddog_ffe_Handle_Configuration));

*config = NULL; // Initialize the handle to NULL

return TypedData_Wrap_Struct(klass, &configuration_typed_data, config);

}

static void configuration_free(void *ptr) {

ddog_ffe_Handle_Configuration *config = (ddog_ffe_Handle_Configuration *) ptr;

if (config && *config) {

ddog_ffe_configuration_drop(config);

}

ruby_xfree(ptr);

}

static void configuration_free(void *ptr) {

ddog_ffe_configuration_drop(&(ddog_ffe_Handle_Configuration) ptr);

}

Similarly, for all other handle types

dd-oleksii · 2025-11-07T09:40:57Z

ext/libdatadog_api/feature_flags.c

+  // Check if resolution_details is NULL (no assignment returned)
+  if (resolution_details_out == NULL) {
+    return Qnil;
+  }


nit: ddog_ffe_get_assignment always returns a result, so this check is not necessary

dd-oleksii · 2025-11-07T09:46:03Z

ext/libdatadog_api/feature_flags.c

+  VALUE resolution_details_obj = resolution_details_alloc(resolution_details_class);
+
+  ddog_ffe_Handle_ResolutionDetails *resolution_details_ptr;
+  TypedData_Get_Struct(resolution_details_obj, ddog_ffe_Handle_ResolutionDetails, &resolution_details_typed_data, resolution_details_ptr);
+
+  *resolution_details_ptr = resolution_details_out;
+
+  return resolution_details_obj;


nit re using handles directly without extra allocation, this would simplify this section:

Suggested change

VALUE resolution_details_obj = resolution_details_alloc(resolution_details_class);

ddog_ffe_Handle_ResolutionDetails *resolution_details_ptr;

TypedData_Get_Struct(resolution_details_obj, ddog_ffe_Handle_ResolutionDetails, &resolution_details_typed_data, resolution_details_ptr);

*resolution_details_ptr = resolution_details_out;

return resolution_details_obj;

return TypedData_Wrap_Struct(resolution_details_class, &resolution_details_typed_data, resolution_details_out);

dd-oleksii · 2025-11-07T09:49:31Z

ext/libdatadog_api/feature_flags.c

+  rb_define_method(resolution_details_class, "value", resolution_details_get_value, 0);
+  rb_define_method(resolution_details_class, "reason", resolution_details_get_reason, 0);
+  rb_define_method(resolution_details_class, "error_code", resolution_details_get_error_code, 0);
+  rb_define_method(resolution_details_class, "error_message", resolution_details_get_error_message, 0);
+  rb_define_method(resolution_details_class, "variant", resolution_details_get_variant, 0);
+  rb_define_method(resolution_details_class, "allocation_key", resolution_details_get_allocation_key, 0);
+  rb_define_method(resolution_details_class, "do_log", resolution_details_get_do_log, 0);


major: need to add flag_metadata and extra_logging methods

dd-oleksii · 2025-11-07T09:54:08Z

lib/datadog/open_feature/binding/native_evaluator.rb

+          # Handle the case where native evaluation returns all-nil results
+          # This indicates the native evaluator isn't working properly or flag not found
+          if result.value.nil? && result.error_code.nil? && result.reason.nil?
+            # All fields are nil - treat as evaluation failure
+            ResolutionDetails.new(
+              value: default_value,
+              variant: nil,
+              error_code: :flag_not_found,
+              error_message: "Native evaluation returned empty result",
+              reason: :error,
+              allocation_key: nil,
+              do_log: nil
+            )


major: this is an internal error, not not found case. We should report it as such

dd-oleksii · 2025-11-07T09:57:57Z

ext/libdatadog_api/feature_flags.c

+  switch (error_code) {
+    case DDOG_FFE_ERROR_CODE_TYPE_MISMATCH:
+      return ID2SYM(rb_intern("type_mismatch"));
+    case DDOG_FFE_ERROR_CODE_PARSE_ERROR:
+      return ID2SYM(rb_intern("parse_error"));
+    case DDOG_FFE_ERROR_CODE_FLAG_NOT_FOUND:
+      return ID2SYM(rb_intern("flag_not_found"));
+    case DDOG_FFE_ERROR_CODE_TARGETING_KEY_MISSING:
+      return ID2SYM(rb_intern("targeting_key_missing"));
+    case DDOG_FFE_ERROR_CODE_INVALID_CONTEXT:
+      return ID2SYM(rb_intern("invalid_context"));
+    case DDOG_FFE_ERROR_CODE_PROVIDER_NOT_READY:
+      return ID2SYM(rb_intern("provider_not_ready"));
+    case DDOG_FFE_ERROR_CODE_GENERAL:
+      return ID2SYM(rb_intern("general"));
+    default:
+      return Qnil;
+  }


minor: "general" is a safer default

Suggested change

switch (error_code) {

case DDOG_FFE_ERROR_CODE_TYPE_MISMATCH:

return ID2SYM(rb_intern("type_mismatch"));

case DDOG_FFE_ERROR_CODE_PARSE_ERROR:

return ID2SYM(rb_intern("parse_error"));

case DDOG_FFE_ERROR_CODE_FLAG_NOT_FOUND:

return ID2SYM(rb_intern("flag_not_found"));

case DDOG_FFE_ERROR_CODE_TARGETING_KEY_MISSING:

return ID2SYM(rb_intern("targeting_key_missing"));

case DDOG_FFE_ERROR_CODE_INVALID_CONTEXT:

return ID2SYM(rb_intern("invalid_context"));

case DDOG_FFE_ERROR_CODE_PROVIDER_NOT_READY:

return ID2SYM(rb_intern("provider_not_ready"));

case DDOG_FFE_ERROR_CODE_GENERAL:

return ID2SYM(rb_intern("general"));

default:

return Qnil;

}

switch (error_code) {

case DDOG_FFE_ERROR_CODE_OK:

return Qnil;

case DDOG_FFE_ERROR_CODE_TYPE_MISMATCH:

return ID2SYM(rb_intern("type_mismatch"));

case DDOG_FFE_ERROR_CODE_PARSE_ERROR:

return ID2SYM(rb_intern("parse_error"));

case DDOG_FFE_ERROR_CODE_FLAG_NOT_FOUND:

return ID2SYM(rb_intern("flag_not_found"));

case DDOG_FFE_ERROR_CODE_TARGETING_KEY_MISSING:

return ID2SYM(rb_intern("targeting_key_missing"));

case DDOG_FFE_ERROR_CODE_INVALID_CONTEXT:

return ID2SYM(rb_intern("invalid_context"));

case DDOG_FFE_ERROR_CODE_PROVIDER_NOT_READY:

return ID2SYM(rb_intern("provider_not_ready"));

case DDOG_FFE_ERROR_CODE_GENERAL:

return ID2SYM(rb_intern("general"));

default:

return ID2SYM(rb_intern("general"));

}

dd-oleksii · 2025-11-07T10:03:56Z

lib/datadog/open_feature/binding/native_evaluator.rb

+          elsif result.error_code || result.value.nil?
+            # Normal error condition or nil value with error_code
+            ResolutionDetails.new(
+              value: default_value,
+              variant: result.variant,
+              error_code: result.error_code || :flag_not_found,
+              error_message: result.error_message || "Flag evaluation failed",
+              reason: result.reason || :error,
+              allocation_key: result.allocation_key,
+              do_log: result.do_log
+            )


major 🐛: this incorrectly squashes non-error evaluation that resulted in no value (e.g., flag disabled or default allocation null, or null json flags) into error.

Suggested change

elsif result.error_code || result.value.nil?

# Normal error condition or nil value with error_code

ResolutionDetails.new(

value: default_value,

variant: result.variant,

error_code: result.error_code || :flag_not_found,

error_message: result.error_message || "Flag evaluation failed",

reason: result.reason || :error,

allocation_key: result.allocation_key,

do_log: result.do_log

)

elsif result.variant.nil?

# Normal error condition or nil value with error_code

ResolutionDetails.new(

value: default_value,

variant: result.variant,

error_code: result.error_code,

error_message: result.error_message,

reason: result.reason,

allocation_key: result.allocation_key,

do_log: result.do_log

)

dd-oleksii · 2025-11-07T10:05:44Z

lib/datadog/open_feature/binding/native_evaluator.rb

+          # First try to handle evaluation using Ruby-based logic
+          ruby_result = try_ruby_evaluation(flag_key, evaluation_context, default_value)
+          return ruby_result if ruby_result


major: native evaluation should be tried first?

Ah yeah this is just some mess from moving code around while I debug. The evaluation code in Ruby shouldn't be used at all (and probably should be deleted) after we get the binding working

- Recovered setup_ffe.sh script with libdatadog build automation - Recovered C extension feature_flags.c with function-based FFI API - Recovered comprehensive binding tests (saved as binding_spec_recovered.rb) - These files were accidentally lost when rebasing onto target branch that used different FFE approach

- Recover setup_ffe.sh, feature_flags.c, and tests lost during rebase - Add NativeEvaluator class using native C extension methods - Update Configuration/EvaluationContext to support native and Ruby modes - Add Binding.supported? method and improved setup script cleanup - Fix library_config.h API compatibility (ddog_CStr -> ddog_CharSlice)

- Add NativeEvaluator class that uses libdatadog FFI for flag evaluation - Integrate C extension (feature_flags.c) with OpenFeature::Binding module - Add automatic libdatadog_api extension loading in binding.rb - Implement ResolutionDetails class backed by native C structures - Add comprehensive native_evaluator_spec.rb test suite (14 tests) - Update Configuration class to support native mode initialization - Fix EvaluationContext to properly detect native method availability - Update setup_ffe.sh to test native evaluator end-to-end - Add null handle validation in native C functions - Temporarily disable incompatible library_config API calls

… fallback - Add native_evaluator_test_cases_spec.rb with 212 comprehensive fixture tests matching InternalEvaluator coverage - Implement hybrid Ruby-first evaluation with native fallback in NativeEvaluator for improved reliability - Add Ruby-based evaluation for disabled flags and simple allocation scenarios - Update setup_ffe.sh to run comprehensive fixture tests as part of FFE verification - Fix InternalEvaluator fixture tests to use flat ResolutionDetails structure instead of flag_metadata - Update test validation to check allocation_key and do_log directly on ResolutionDetails - Enhance NativeEvaluator to handle both 2-parameter and 4-parameter get_assignment signatures - Add comprehensive error handling and debug logging for native evaluation troubleshooting

sameerank · 2025-11-10T04:28:03Z

Accidental merge. Re-drafting here: #5034

github-actions bot added core Involves Datadog core libraries integrations Involves tracing integrations tracing labels Oct 29, 2025

sameerank changed the base branch from master to add-openfeature-component October 29, 2025 15:06

sameerank force-pushed the sameerank/FFL-1273-Bindings-for-ffe-in-openfeature-provider branch from a9fce8c to 5b61f55 Compare October 29, 2025 19:48

This was referenced Oct 29, 2025

[FFL-1273] bindings for libdatadog datadog ffe api #5001

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[FFL-1284] Create datadog-ffe-ffi crate DataDog/libdatadog#1282

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[NO-TICKET] Refresh libdatadog dev docs + remove accidental dependency on profiling.h #5018

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sameerank force-pushed the sameerank/FFL-1273-Bindings-for-ffe-in-openfeature-provider branch from 075de60 to 81c3973 Compare November 7, 2025 01:06

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sameerank changed the base branch from add-openfeature-component to sameerank/FFL-1273-Bindings-for-libdatadog-datadog-ffe-API November 7, 2025 01:07

github-actions bot added the profiling Involves Datadog profiling label Nov 7, 2025

sameerank changed the base branch from sameerank/FFL-1273-Bindings-for-libdatadog-datadog-ffe-API to FFL-1361-Evaluation-in-binding-in-ruby November 7, 2025 01:15

sameerank force-pushed the sameerank/FFL-1273-Bindings-for-ffe-in-openfeature-provider branch from 88e5d73 to da285f5 Compare November 7, 2025 03:35

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[FFL-1361] Evaluation in binding in ruby #5022

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dd-oleksii reviewed Nov 7, 2025

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sameerank force-pushed the FFL-1361-Evaluation-in-binding-in-ruby branch from 6f4c1fd to 94c24c2 Compare November 10, 2025 02:42

sameerank added 4 commits November 9, 2025 18:49

Clean up merge conflicts in component spec

11cabd5

sameerank force-pushed the sameerank/FFL-1273-Bindings-for-ffe-in-openfeature-provider branch from 3812d17 to 11cabd5 Compare November 10, 2025 02:52

sameerank merged commit 11cabd5 into FFL-1361-Evaluation-in-binding-in-ruby Nov 10, 2025
4 of 7 checks passed

sameerank deleted the sameerank/FFL-1273-Bindings-for-ffe-in-openfeature-provider branch November 10, 2025 03:38

github-actions bot added this to the 2.23.0 milestone Nov 10, 2025

sameerank restored the sameerank/FFL-1273-Bindings-for-ffe-in-openfeature-provider branch November 10, 2025 04:16

sameerank deleted the sameerank/FFL-1273-Bindings-for-ffe-in-openfeature-provider branch November 10, 2025 04:27

sameerank removed this from the 2.23.0 milestone Nov 11, 2025

		Check_Type(targeting_key, T_STRING);
		Check_Type(attributes_hash, T_HASH);

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sameerank commented Oct 29, 2025

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ivoanjo commented Nov 3, 2025

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Benchmarks

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sameerank commented Nov 10, 2025

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