fix(go/core): flow name is not passed to the context (#3718)

Author: olte36

go/core/flow.go

@@ -48,7 +48,9 @@ type flowContext struct {
 // DefineFlow creates a Flow that runs fn, and registers it as an action. fn takes an input of type In and returns an output of type Out.
 func DefineFlow[In, Out any](r api.Registry, name string, fn Func[In, Out]) *Flow[In, Out, struct{}] {
 	return (*Flow[In, Out, struct{}])(DefineAction(r, name, api.ActionTypeFlow, nil, nil, func(ctx context.Context, input In) (Out, error) {
-		fc := &flowContext{}
+		fc := &flowContext{
+			flowName: name,
+		}
 		ctx = flowContextKey.NewContext(ctx, fc)
 		return fn(ctx, input)
 	}))
@@ -65,7 +67,9 @@ func DefineFlow[In, Out any](r api.Registry, name string, fn Func[In, Out]) *Flo
 // Otherwise, it should ignore the callback and just return a result.
 func DefineStreamingFlow[In, Out, Stream any](r api.Registry, name string, fn StreamingFunc[In, Out, Stream]) *Flow[In, Out, Stream] {
 	return (*Flow[In, Out, Stream])(DefineStreamingAction(r, name, api.ActionTypeFlow, nil, nil, func(ctx context.Context, input In, cb func(context.Context, Stream) error) (Out, error) {
-		fc := &flowContext{}
+		fc := &flowContext{
+			flowName: name,
+		}
 		ctx = flowContextKey.NewContext(ctx, fc)
 		return fn(ctx, input, cb)
 	}))

go/core/flow_test.go

@@ -66,3 +66,26 @@ func TestRunFlow(t *testing.T) {
 		t.Errorf("got %d, want %d", got, want)
 	}
 }
+
+func TestFlowNameFromContext(t *testing.T) {
+	r := registry.New()
+	flows := []*Flow[struct{}, string, struct{}]{
+		DefineFlow(r, "DefineFlow", func(ctx context.Context, _ struct{}) (string, error) {
+			return FlowNameFromContext(ctx), nil
+		}),
+		DefineStreamingFlow(r, "DefineStreamingFlow", func(ctx context.Context, _ struct{}, s StreamCallback[struct{}]) (string, error) {
+			return FlowNameFromContext(ctx), nil
+		}),
+	}
+	for _, flow := range flows {
+		t.Run(flow.Name(), func(t *testing.T) {
+			got, err := flow.Run(context.Background(), struct{}{})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if want := flow.Name(); got != want {
+				t.Errorf("got '%s', want '%s'", got, want)
+			}
+		})
+	}
+}