feat: Add statsig interceptor package

pkg/interceptors/statsig.go

@@ -0,0 +1,80 @@
+package interceptors
+
+import (
+	"context"
+
+	grpcmiddleware "github.com/grpc-ecosystem/go-grpc-middleware"
+	"google.golang.org/grpc"
+
+	sdkstatsigcontext "github.com/scribd/go-sdk/pkg/context/statsig"
+	"github.com/scribd/go-sdk/pkg/statsig"
+)
+
+// ExperimentUnaryServerInterceptor returns a unary server interceptor
+// that adds sdkstatsigcontext.GetExperimentFunc to the context.
+func ExperimentUnaryServerInterceptor(experiment string) grpc.UnaryServerInterceptor {
+	return func(
+		ctx context.Context,
+		req interface{},
+		info *grpc.UnaryServerInfo,
+		handler grpc.UnaryHandler,
+	) (interface{}, error) {
+		x := statsig.GetExperiment(experiment)
+		newCtx := sdkstatsigcontext.ExperimentToContext(ctx, x)
+		return handler(newCtx, req)
+	}
+}
+
+// ExperimentStreamServerInterceptor returns a streaming server interceptor
+// that sdkstatsigcontext.GetExperimentFunc to the context.
+func ExperimentStreamServerInterceptor(experiment string) grpc.StreamServerInterceptor {
+	return func(
+		srv interface{},
+		stream grpc.ServerStream,
+		info *grpc.StreamServerInfo,
+		handler grpc.StreamHandler,
+	) error {
+		x := statsig.GetExperiment(experiment)
+		newCtx := sdkstatsigcontext.ExperimentToContext(stream.Context(), x)
+
+		wrapped := grpcmiddleware.WrapServerStream(stream)
+		wrapped.WrappedContext = newCtx
+
+		return handler(srv, wrapped)
+	}
+}
+
+// FeatureFlagUnaryServerInterceptor returns a unary server interceptor
+// that adds sdkstatsigcontext.GetFeatureFlagFunc to the context.
+func FeatureFlagUnaryServerInterceptor(featureFlag string) grpc.UnaryServerInterceptor {
+	return func(
+		ctx context.Context,
+		req interface{},
+		info *grpc.UnaryServerInfo,
+		handler grpc.UnaryHandler,
+	) (interface{}, error) {
+		ff := statsig.GetFeatureFlag(featureFlag)
+		newCtx := sdkstatsigcontext.FeatureFlagToContext(ctx, ff)
+
+		return handler(newCtx, req)
+	}
+}
+
+// FeatureFlagStreamServerInterceptor returns a streaming server interceptor
+// that sdkstatsigcontext.GetFeatureFlagFunc to the context.
+func FeatureFlagStreamServerInterceptor(featureFlag string) grpc.StreamServerInterceptor {
+	return func(
+		srv interface{},
+		stream grpc.ServerStream,
+		info *grpc.StreamServerInfo,
+		handler grpc.StreamHandler,
+	) error {
+		ff := statsig.GetFeatureFlag(featureFlag)
+		newCtx := sdkstatsigcontext.FeatureFlagToContext(stream.Context(), ff)
+
+		wrapped := grpcmiddleware.WrapServerStream(stream)
+		wrapped.WrappedContext = newCtx
+
+		return handler(srv, wrapped)
+	}
+}