feat: multi-project support via selectors and flagSetId namespacing

CONTRIBUTING.md

@@ -83,6 +83,13 @@ curl -X POST  -d '{"context":{}}' 'http://localhost:8016/ofrep/v1/evaluate/flags
 grpcurl -import-path schemas/protobuf/flagd/evaluation/v1/ -proto evaluation.proto -plaintext -d '{}' localhost:8013 flagd.evaluation.v1.Service/ResolveAll | jq
 ```
 
+#### Remote event streaming via gRPC
+
+```sh
+# notifies of flag changes (but does not evaluate)
+grpcurl -import-path schemas/protobuf/flagd/evaluation/v1/ -proto evaluation.proto -plaintext -d '{}' localhost:8013 flagd.evaluation.v1.Service/EventStream
+```
+
 #### Flag configuration fetch via gRPC
 
 ```sh

Makefile

@@ -47,8 +47,6 @@ test-flagd:
 	go test -race -covermode=atomic -cover -short ./flagd/pkg/... -coverprofile=flagd-coverage.out
 test-flagd-proxy:
 	go test -race -covermode=atomic -cover -short ./flagd-proxy/pkg/... -coverprofile=flagd-proxy-coverage.out
-flagd-integration-test: # dependent on ./bin/flagd start -f file:test-harness/flags/testing-flags.json -f file:test-harness/flags/custom-ops.json -f file:test-harness/flags/evaluator-refs.json -f file:test-harness/flags/zero-flags.json
-	go test -cover ./test/integration $(ARGS)
 flagd-benchmark-test:
 	go test -bench=Bench -short -benchtime=5s -benchmem ./core/... | tee benchmark.txt
 flagd-integration-test-harness:
@@ -59,7 +57,9 @@ flagd-integration-test: # dependent on flagd-e2e-test-harness if not running in
 run: # default to flagd
 	make run-flagd
 run-flagd:
-	cd flagd; go run main.go start -f file:../config/samples/example_flags.flagd.json
+	cd flagd; go run main.go start -f file:../config/samples/example_flags.flagd.json 
+run-flagd-selector-demo:
+	cd flagd; go run main.go start -f file:../config/samples/example_flags.flagd.json -f file:../config/samples/example_flags.flagd.2.json
 install:
 	cp systemd/flagd.service /etc/systemd/system/flagd.service
 	mkdir -p /etc/flagd

config/samples/example_flags.flagd.2.json

@@ -0,0 +1,17 @@
+{
+  "$schema": "https://flagd.dev/schema/v0/flags.json",
+  "metadata": {
+    "flagSetId": "other",
+    "version": "v1"
+  },
+  "flags": {
+    "myStringFlag": {
+      "state": "ENABLED",
+      "variants": {
+        "dupe1": "dupe1",
+        "dupe2": "dupe2"
+      },
+      "defaultVariant": "dupe1"
+    }
+  }
+}

core/pkg/evaluator/fractional_test.go

@@ -11,6 +11,8 @@ import (
 )
 
 func TestFractionalEvaluation(t *testing.T) {
+	const source = "testSource"
+	var sources = []string{source}
 	ctx := context.Background()
 
 	commonFlags := Flags{
@@ -458,8 +460,13 @@ func TestFractionalEvaluation(t *testing.T) {
 	for name, tt := range tests {
 		t.Run(name, func(t *testing.T) {
 			log := logger.NewLogger(nil, false)
-			je := NewJSON(log, store.NewFlags())
-			je.store.Update("", "", tt.flags.Flags, model.Metadata{})
+			s, err := store.NewStore(log, sources)
+			if err != nil {
+				t.Fatalf("NewStore failed: %v", err)
+			}
+
+			je := NewJSON(log, s)
+			je.store.Update(source, tt.flags.Flags, model.Metadata{})
 
 			value, variant, reason, _, err := resolve[string](ctx, reqID, tt.flagKey, tt.context, je.evaluateVariant)
 
@@ -486,6 +493,8 @@ func TestFractionalEvaluation(t *testing.T) {
 }
 
 func BenchmarkFractionalEvaluation(b *testing.B) {
+	const source = "testSource"
+	var sources = []string{source}
 	ctx := context.Background()
 
 	flags := Flags{
@@ -587,8 +596,13 @@ func BenchmarkFractionalEvaluation(b *testing.B) {
 	for name, tt := range tests {
 		b.Run(name, func(b *testing.B) {
 			log := logger.NewLogger(nil, false)
-			je := NewJSON(log, store.NewFlags())
-			je.store.Update("", "", tt.flags.Flags, model.Metadata{})
+			s, err := store.NewStore(log, sources)
+			if err != nil {
+				b.Fatalf("NewStore failed: %v", err)
+			}
+			je := NewJSON(log, s)
+			je.store.Update(source, tt.flags.Flags, model.Metadata{})
+
 			for i := 0; i < b.N; i++ {
 				value, variant, reason, _, err := resolve[string](
 					ctx, reqID, tt.flagKey, tt.context, je.evaluateVariant)

core/pkg/evaluator/ievaluator.go

@@ -35,7 +35,7 @@ IEvaluator is an extension of IResolver, allowing storage updates and retrievals
 */
 type IEvaluator interface {
 	GetState() (string, error)
-	SetState(payload sync.DataSync) (model.Metadata, bool, error)
+	SetState(payload sync.DataSync) (map[string]interface{}, bool, error)
 	IResolver
 }
 

core/pkg/evaluator/json.go

@@ -118,7 +118,7 @@ func (je *JSON) SetState(payload sync.DataSync) (map[string]interface{}, bool, e
 	var events map[string]interface{}
 	var reSync bool
 
-	events, reSync = je.store.Update(payload.Source, payload.Selector, definition.Flags, definition.Metadata)
+	events, reSync = je.store.Update(payload.Source, definition.Flags, definition.Metadata)
 
 	// Number of events correlates to the number of flags changed through this sync, record it
 	span.SetAttributes(attribute.Int("feature_flag.change_count", len(events)))
@@ -149,8 +149,14 @@ func (je *Resolver) ResolveAllValues(ctx context.Context, reqID string, context
 	_, span := je.tracer.Start(ctx, "resolveAll")
 	defer span.End()
 
-	var err error
-	allFlags, flagSetMetadata, err := je.store.GetAll(ctx)
+	var selector store.Selector
+	s := ctx.Value(store.SelectorContextKey{})
+	if s != nil {
+		selector = s.(store.Selector)
+	} else {
+		selector = store.NewSelector("")
+	}
+	allFlags, flagSetMetadata, err := je.store.GetAll(ctx, &selector)
 	if err != nil {
 		return nil, flagSetMetadata, fmt.Errorf("error retreiving flags from the store: %w", err)
 	}
@@ -301,19 +307,24 @@ func resolve[T constraints](ctx context.Context, reqID string, key string, conte
 func (je *Resolver) evaluateVariant(ctx context.Context, reqID string, flagKey string, evalCtx map[string]any) (
 	variant string, variants map[string]interface{}, reason string, metadata map[string]interface{}, err error,
 ) {
-	flag, metadata, ok := je.store.Get(ctx, flagKey)
-	if !ok {
+
+	var selector store.Selector
+	s := ctx.Value(store.SelectorContextKey{})
+	if s != nil {
+		selector = s.(store.Selector)
+	} else {
+		selector = store.NewSelector("")
+	}
+	if s != nil {
+		selector = s.(store.Selector)
+	}
+	flag, metadata, err := je.store.Get(ctx, flagKey, &selector)
+	if err != nil {
 		// flag not found
 		je.Logger.DebugWithID(reqID, fmt.Sprintf("requested flag could not be found: %s", flagKey))
 		return "", map[string]interface{}{}, model.ErrorReason, metadata, errors.New(model.FlagNotFoundErrorCode)
 	}
 
-	// add selector to evaluation metadata
-	selector := je.store.SelectorForFlag(ctx, flag)
-	if selector != "" {
-		metadata[SelectorMetadataKey] = selector
-	}
-
 	for key, value := range flag.Metadata {
 		// If value is not nil or empty, copy to metadata
 		if value != nil {