feat(cosmos): publish event when x/swingset storage is modified

golang/cosmos/x/swingset/keeper/keeper.go

@@ -170,6 +170,10 @@ func (k Keeper) SetStorage(ctx sdk.Context, path string, storage *types.Storage)
 		dataStore.Set(pathKey, k.cdc.MustMarshalLengthPrefixed(storage))
 	}
 
+	ctx.EventManager().EmitEvent(
+		types.NewStorageEvent(path, storage.Value),
+	)
+
 	// Update the parent keys.
 	pathComponents := strings.Split(path, ".")
 	for i := len(pathComponents) - 1; i >= 0; i-- {

golang/cosmos/x/swingset/types/events.go

@@ -0,0 +1,25 @@
+package types
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+// swingset module event types
+const (
+	EventTypeStorage = "storage"
+
+	AttributeKeyPath  = "path"
+	AttributeKeyValue = "value"
+
+	AttributeValueCategory = ModuleName
+)
+
+// NewStorageSetEvent constructs a new storage change sdk.Event
+// nolint: interfacer
+func NewStorageEvent(path, value string) sdk.Event {
+	return sdk.NewEvent(
+		EventTypeStorage,
+		sdk.NewAttribute(AttributeKeyPath, path),
+		sdk.NewAttribute(AttributeKeyValue, value),
+	)
+}