fix: unique constraints on instance domain events (#3635)

internal/eventstore/eventstore.go

@@ -104,10 +104,14 @@ func commandsToRepository(instanceID string, cmds []Command) (events []*reposito
 func uniqueConstraintsToRepository(instanceID string, constraints []*EventUniqueConstraint) (uniqueConstraints []*repository.UniqueConstraint) {
 	uniqueConstraints = make([]*repository.UniqueConstraint, len(constraints))
 	for i, constraint := range constraints {
+		var id string
+		if !constraint.IsGlobal {
+			id = instanceID
+		}
 		uniqueConstraints[i] = &repository.UniqueConstraint{
 			UniqueType:   constraint.UniqueType,
 			UniqueField:  constraint.UniqueField,
-			InstanceID:   instanceID,
+			InstanceID:   id,
 			Action:       uniqueConstraintActionToRepository(constraint.Action),
 			ErrorMessage: constraint.ErrorMessage,
 		}

internal/eventstore/unique_constraint.go

@@ -9,6 +9,8 @@ type EventUniqueConstraint struct {
 	Action UniqueConstraintAction
 	//ErrorMessage defines the translation file key for the error message
 	ErrorMessage string
+	//IsGlobal defines if the unique constraint is globally unique or just within a single instance
+	IsGlobal bool
 }
 
 type UniqueConstraintAction int32
@@ -39,3 +41,27 @@ func NewRemoveEventUniqueConstraint(
 		Action:      UniqueConstraintRemove,
 	}
 }
+
+func NewAddGlobalEventUniqueConstraint(
+	uniqueType,
+	uniqueField,
+	errMessage string) *EventUniqueConstraint {
+	return &EventUniqueConstraint{
+		UniqueType:   uniqueType,
+		UniqueField:  uniqueField,
+		ErrorMessage: errMessage,
+		IsGlobal:     true,
+		Action:       UniqueConstraintAdd,
+	}
+}
+
+func NewRemoveGlobalEventUniqueConstraint(
+	uniqueType,
+	uniqueField string) *EventUniqueConstraint {
+	return &EventUniqueConstraint{
+		UniqueType:  uniqueType,
+		UniqueField: uniqueField,
+		IsGlobal:    true,
+		Action:      UniqueConstraintRemove,
+	}
+}