more

pkg/actor/grain_pool.go

@@ -6,8 +6,13 @@ import (
 	"github.com/gogo/protobuf/proto"
 )
 
+type MutationResult[V any] struct {
+	Result    V             `json:"result"`
+	Mutations []ApplyResult `json:"mutations,omitempty"`
+}
+
 type GrainPool[V any] interface {
-	Apply(id uint64, mutation ...proto.Message) (V, error)
+	Apply(id uint64, mutation ...proto.Message) (*MutationResult[V], error)
 	Get(id uint64) (V, error)
 	OwnerHost(id uint64) (Host, bool)
 	Hostname() string

pkg/actor/mutation_registry.go

@@ -9,8 +9,14 @@ import (
 	"github.com/gogo/protobuf/proto"
 )
 
+type ApplyResult struct {
+	Type     string        `json:"type"`
+	Mutation proto.Message `json:"mutation"`
+	Error    error         `json:"error,omitempty"`
+}
+
 type MutationRegistry interface {
-	Apply(grain any, msg ...proto.Message) error
+	Apply(grain any, msg ...proto.Message) ([]ApplyResult, error)
 	RegisterMutations(handlers ...MutationHandler)
 	Create(typeName string) (proto.Message, bool)
 	GetTypeName(msg proto.Message) (string, bool)
@@ -145,12 +151,14 @@ func (r *ProtoMutationRegistry) Create(typeName string) (proto.Message, bool) {
 // Returns updated grain if successful.
 //
 // If the mutation is not registered, returns (nil, ErrMutationNotRegistered).
-func (r *ProtoMutationRegistry) Apply(grain any, msg ...proto.Message) error {
+func (r *ProtoMutationRegistry) Apply(grain any, msg ...proto.Message) ([]ApplyResult, error) {
+	results := make([]ApplyResult, 0, len(msg))
+
 	if grain == nil {
-		return fmt.Errorf("nil grain")
+		return results, fmt.Errorf("nil grain")
 	}
 	if msg == nil {
-		return fmt.Errorf("nil mutation message")
+		return results, fmt.Errorf("nil mutation message")
 	}
 
 	for _, m := range msg {
@@ -159,18 +167,18 @@ func (r *ProtoMutationRegistry) Apply(grain any, msg ...proto.Message) error {
 		entry, ok := r.mutationRegistry[rt]
 		r.mutationRegistryMu.RUnlock()
 		if !ok {
-			return ErrMutationNotRegistered
-		}
-		if err := entry.Handle(grain, m); err != nil {
-			return err
+			results = append(results, ApplyResult{Error: ErrMutationNotRegistered, Type: rt.Name(), Mutation: m})
+			continue
 		}
+		err := entry.Handle(grain, m)
+		results = append(results, ApplyResult{Error: err, Type: rt.Name(), Mutation: m})
 	}
 
 	// if entry.updateTotals {
 	// 	grain.UpdateTotals()
 	// }
 
-	return nil
+	return results, nil
 }
 
 // RegisteredMutations returns metadata for all registered mutations (snapshot).

pkg/actor/mutation_registry_test.go

@@ -78,7 +78,7 @@ func TestRegisteredMutationBasics(t *testing.T) {
 	// Apply happy path
 	state := &cartState{}
 	add := &messages.AddItem{ItemId: 42, Quantity: 3, Sku: "ABC"}
-	if err := reg.Apply(state, add); err != nil {
+	if _, err := reg.Apply(state, add); err != nil {
 		t.Fatalf("Apply returned error: %v", err)
 	}
 	if state.calls != 1 {
@@ -89,17 +89,17 @@ func TestRegisteredMutationBasics(t *testing.T) {
 	}
 
 	// Apply nil grain
-	if err := reg.Apply(nil, add); err == nil {
+	if _, err := reg.Apply(nil, add); err == nil {
 		t.Fatalf("expected error for nil grain")
 	}
 
 	// Apply nil message
-	if err := reg.Apply(state, nil); err == nil {
+	if _, err := reg.Apply(state, nil); err == nil {
 		t.Fatalf("expected error for nil mutation message")
 	}
 
 	// Apply unregistered message
-	if err := reg.Apply(state, &messages.Noop{}); !errors.Is(err, ErrMutationNotRegistered) {
+	if _, err := reg.Apply(state, &messages.Noop{}); !errors.Is(err, ErrMutationNotRegistered) {
 		t.Fatalf("expected ErrMutationNotRegistered, got %v", err)
 	}
 }

pkg/actor/simple_grain_pool.go

@@ -371,13 +371,15 @@ func (p *SimpleGrainPool[V]) getOrClaimGrain(id uint64) (Grain[V], error) {
 // var ErrNotOwner = fmt.Errorf("not owner")
 
 // Apply applies a mutation to a grain.
-func (p *SimpleGrainPool[V]) Apply(id uint64, mutation ...proto.Message) (*V, error) {
+func (p *SimpleGrainPool[V]) Apply(id uint64, mutation ...proto.Message) (*MutationResult[*V], error) {
 	grain, err := p.getOrClaimGrain(id)
 	if err != nil {
 		return nil, err
 	}
-	if applyErr := p.mutationRegistry.Apply(grain, mutation...); applyErr != nil {
-		return nil, applyErr
+
+	mutations, err := p.mutationRegistry.Apply(grain, mutation...)
+	if err != nil {
+		return nil, err
 	}
 	if p.storage != nil {
 		go func() {
@@ -386,7 +388,14 @@ func (p *SimpleGrainPool[V]) Apply(id uint64, mutation ...proto.Message) (*V, er
 			}
 		}()
 	}
-	return grain.GetCurrentState()
+	result, err := grain.GetCurrentState()
+	if err != nil {
+		return nil, err
+	}
+	return &MutationResult[*V]{
+		Result:    result,
+		Mutations: mutations,
+	}, nil
 }
 
 // Get returns the current state of a grain.

pkg/voucher/service.go

@@ -1,6 +1,9 @@
 package voucher
 
-import "math"
+import (
+	"errors"
+	"math"
+)
 
 type Rule struct {
 	Type  string `json:"type"`
@@ -20,8 +23,13 @@ type Service struct {
 
 }
 
+var ErrInvalidCode = errors.New("invalid vouchercode")
+
 func (s *Service) GetVoucher(code string) (*Voucher, error) {
 	value := int64(math.Round(100 * math.Pow(10, 2)))
+	if code == "" {
+		return nil, ErrInvalidCode
+	}
 	return &Voucher{
 		Code:     code,
 		Value:    value,