feat(cosmos): impose defaults when sending VM actions

golang/cosmos/vm/action.go

@@ -0,0 +1,130 @@
+package vm
+
+import (
+	"reflect"
+	"strconv"
+	"time"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+var (
+	zeroTime                = time.Time{}
+	actionHeaderType        = reflect.TypeOf(ActionHeader{})
+	_                Action = &ActionHeader{}
+)
+
+// Jsonable is a value, j, that can be passed through json.Marshal(j).
+type Jsonable interface{}
+
+type Action interface {
+	GetActionHeader() ActionHeader
+}
+
+// ActionPusher enqueues data for later consumption by the controller.
+type ActionPusher func(ctx sdk.Context, action Action) error
+
+// ActionHeader should be embedded in all actions.  It is populated by PopulateAction.
+type ActionHeader struct {
+	// Type defaults to the `actionType:"..."` tag of the embedder's ActionHeader field.
+	Type string `json:"type"`
+	// BlockHeight defaults to sdk.Context.BlockHeight().
+	BlockHeight int64 `json:"blockHeight,omitempty"`
+	// BlockTime defaults to sdk.Context.BlockTime().Unix().
+	BlockTime int64 `json:"blockTime,omitempty"`
+}
+
+func (ah ActionHeader) GetActionHeader() ActionHeader {
+	return ah
+}
+
+// SetActionHeaderFromContext provides defaults to an ActionHeader.
+func SetActionHeaderFromContext(ctx sdk.Context, actionType string, ah *ActionHeader) {
+	// Default the action type.
+	if len(ah.Type) == 0 {
+		ah.Type = actionType
+	}
+
+	// Default the block height.
+	if ah.BlockHeight == 0 {
+		ah.BlockHeight = ctx.BlockHeight()
+	}
+
+	if ah.BlockTime == 0 {
+		// Only default to a non-zero block time.
+		if blockTime := ctx.BlockTime(); blockTime != zeroTime {
+			ah.BlockTime = blockTime.Unix()
+		}
+	}
+}
+
+// PopulateAction interprets `default:"..."` tags and specially handles an
+// embedded ActionHeader struct.
+func PopulateAction(ctx sdk.Context, action Action) Action {
+	oldRv := reflect.Indirect(reflect.ValueOf(action))
+	if oldRv.Kind() != reflect.Struct {
+		return action
+	}
+
+	// Shallow copy to a new value.
+	rp := reflect.New(oldRv.Type())
+	rv := reflect.Indirect(rp)
+	for i := 0; i < rv.NumField(); i++ {
+		oldField := oldRv.Field(i)
+		field := rv.Field(i)
+		fieldType := rv.Type().Field(i)
+		if !field.CanSet() {
+			continue
+		}
+
+		// Copy from original.
+		field.Set(oldField)
+
+		// Populate any ActionHeader struct.
+		var ahp *ActionHeader
+		if fieldType.Type == actionHeaderType {
+			ahp = field.Addr().Interface().(*ActionHeader)
+		} else if fieldType.Type == reflect.PtrTo(actionHeaderType) {
+			if field.IsNil() {
+				ahp = &ActionHeader{}
+			} else {
+				ahp = field.Interface().(*ActionHeader)
+			}
+		}
+		if ahp != nil {
+			actionTypeTag, _ := fieldType.Tag.Lookup("actionType")
+			ah := *ahp
+			SetActionHeaderFromContext(ctx, actionTypeTag, &ah)
+			if field.Kind() == reflect.Ptr {
+				field.Set(reflect.ValueOf(&ah))
+			} else {
+				field.Set(reflect.ValueOf(ah))
+			}
+			continue
+		}
+
+		// Still zero value, try default struct field tag.
+		defaultTag, _ := fieldType.Tag.Lookup("default")
+		if !field.IsZero() || len(defaultTag) == 0 {
+			continue
+		}
+
+		switch field.Kind() {
+		case reflect.String:
+			field.SetString(defaultTag)
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			if val, err := strconv.ParseInt(defaultTag, 0, 64); err == nil {
+				field.SetInt(val)
+			}
+		case reflect.Bool:
+			if val, err := strconv.ParseBool(defaultTag); err == nil {
+				field.SetBool(val)
+			}
+		case reflect.Float32, reflect.Float64:
+			if val, err := strconv.ParseFloat(defaultTag, 64); err == nil {
+				field.SetFloat(val)
+			}
+		}
+	}
+	return rv.Interface().(Action)
+}

golang/cosmos/vm/action_test.go

@@ -0,0 +1,129 @@
+package vm_test
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/Agoric/agoric-sdk/golang/cosmos/vm"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+var (
+	_ vm.Action = &Trivial{}
+	_ vm.Action = &Defaults{}
+	_ vm.Action = &dataAction{}
+)
+
+type Trivial struct {
+	vm.ActionHeader
+	Abc int
+	def string
+}
+
+type Defaults struct {
+	String string  `default:"abc"`
+	Int    int     `default:"123"`
+	Float  float64 `default:"4.56"`
+	Bool   bool    `default:"true"`
+	Any    interface{}
+}
+
+func (d Defaults) GetActionHeader() vm.ActionHeader {
+	return vm.ActionHeader{}
+}
+
+type dataAction struct {
+	*vm.ActionHeader `actionType:"DATA_ACTION"`
+	Data             []byte
+}
+
+func TestActionContext(t *testing.T) {
+	emptyCtx := sdk.Context{}
+
+	testCases := []struct {
+		name        string
+		ctx         sdk.Context
+		in          vm.Action
+		expectedOut interface{}
+	}{
+		{"nil", emptyCtx, nil, nil},
+		{"no context", emptyCtx,
+			&Trivial{Abc: 123, def: "zot"},
+			&Trivial{Abc: 123, def: "zot"},
+		},
+		{"block height",
+			emptyCtx.WithBlockHeight(998),
+			&Trivial{Abc: 123, def: "zot"},
+			&Trivial{ActionHeader: vm.ActionHeader{BlockHeight: 998}, Abc: 123, def: "zot"},
+		},
+		{"block time",
+			emptyCtx.WithBlockTime(time.UnixMicro(1_000_000)),
+			&Trivial{Abc: 123, def: "zot"},
+			&Trivial{Abc: 123, def: "zot", ActionHeader: vm.ActionHeader{BlockTime: 1}},
+		},
+		{"default tags",
+			emptyCtx,
+			&Defaults{},
+			&Defaults{"abc", 123, 4.56, true, nil},
+		},
+		{"data action defaults",
+			emptyCtx.WithBlockHeight(998).WithBlockTime(time.UnixMicro(1_000_000)),
+			&dataAction{Data: []byte("hello")},
+			&dataAction{Data: []byte("hello"),
+				ActionHeader: &vm.ActionHeader{Type: "DATA_ACTION", BlockHeight: 998, BlockTime: 1}},
+		},
+		{"data action override Type",
+			emptyCtx.WithBlockHeight(998).WithBlockTime(time.UnixMicro(1_000_000)),
+			&dataAction{Data: []byte("hello2"),
+				ActionHeader: &vm.ActionHeader{Type: "DATA_ACTION2"}},
+			&dataAction{Data: []byte("hello2"),
+				ActionHeader: &vm.ActionHeader{Type: "DATA_ACTION2", BlockHeight: 998, BlockTime: 1}},
+		},
+		{"data action override BlockHeight",
+			emptyCtx.WithBlockHeight(998).WithBlockTime(time.UnixMicro(1_000_000)),
+			&dataAction{Data: []byte("hello2"),
+				ActionHeader: &vm.ActionHeader{BlockHeight: 999}},
+			&dataAction{Data: []byte("hello2"),
+				ActionHeader: &vm.ActionHeader{Type: "DATA_ACTION", BlockHeight: 999, BlockTime: 1}},
+		},
+		{"data action override BlockTime",
+			emptyCtx.WithBlockHeight(998).WithBlockTime(time.UnixMicro(1_000_000)),
+			&dataAction{Data: []byte("hello2"),
+				ActionHeader: &vm.ActionHeader{BlockTime: 2}},
+			&dataAction{Data: []byte("hello2"),
+				ActionHeader: &vm.ActionHeader{Type: "DATA_ACTION", BlockHeight: 998, BlockTime: 2}},
+		},
+		{"data action override all defaults",
+			emptyCtx.WithBlockHeight(998).WithBlockTime(time.UnixMicro(1_000_000)),
+			&dataAction{Data: []byte("hello2"),
+				ActionHeader: &vm.ActionHeader{Type: "DATA_ACTION2", BlockHeight: 999, BlockTime: 2}},
+			&dataAction{Data: []byte("hello2"),
+				ActionHeader: &vm.ActionHeader{Type: "DATA_ACTION2", BlockHeight: 999, BlockTime: 2}},
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			jstr := func(in interface{}) string {
+				bz, err := json.Marshal(in)
+				if err != nil {
+					t.Fatal(err)
+				}
+				return string(bz)
+			}
+			jsonIn := jstr(tc.in)
+			out := vm.PopulateAction(tc.ctx, tc.in)
+			jsonIn2 := jstr(tc.in)
+			if jsonIn != jsonIn2 {
+				t.Errorf("unexpected mutated input: %s to %s", jsonIn, jsonIn2)
+			}
+			jsonOut := jstr(out)
+			jsonExpectedOut := jstr(tc.expectedOut)
+			if jsonOut != jsonExpectedOut {
+				t.Errorf("expected %s, got %s", jsonExpectedOut, jsonOut)
+			}
+		})
+	}
+}

golang/cosmos/vm/controller.go

@@ -20,12 +20,6 @@ type ControllerAdmissionMsg interface {
 	IsHighPriority(sdk.Context, interface{}) (bool, error)
 }
 
-// Jsonable is a value, j, that can be passed through json.Marshal(j).
-type Jsonable interface{}
-
-// ActionPusher enqueues data for later consumption by the controller.
-type ActionPusher func(ctx sdk.Context, action Jsonable) error
-
 var wrappedEmptySDKContext = sdk.WrapSDKContext(
 	sdk.Context{}.WithContext(context.Background()),
 )

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

@@ -110,6 +110,16 @@ func NewKeeper(
 	}
 }
 
+func populateAction(ctx sdk.Context, action vm.Action) (vm.Action, error) {
+	action = vm.PopulateAction(ctx, action)
+	ah := action.GetActionHeader()
+	if len(ah.Type) == 0 {
+		return nil, fmt.Errorf("action %q cannot have an empty ActionHeader.Type", action)
+	}
+
+	return action, nil
+}
+
 // pushAction appends an action to the controller's specified inbound queue.
 // The queue is kept in the kvstore so that changes are properly reverted if the
 // kvstore is rolled back.  By the time the block manager runs, it can commit
@@ -118,7 +128,11 @@ func NewKeeper(
 //
 // The inbound queue's format is documented by `makeChainQueue` in
 // `packages/cosmic-swingset/src/helpers/make-queue.js`.
-func (k Keeper) pushAction(ctx sdk.Context, inboundQueuePath string, action vm.Jsonable) error {
+func (k Keeper) pushAction(ctx sdk.Context, inboundQueuePath string, action vm.Action) error {
+	action, err := populateAction(ctx, action)
+	if err != nil {
+		return err
+	}
 	txHash, txHashOk := ctx.Context().Value(baseapp.TxHashContextKey).(string)
 	if !txHashOk {
 		txHash = "unknown"
@@ -143,12 +157,12 @@ func (k Keeper) pushAction(ctx sdk.Context, inboundQueuePath string, action vm.J
 }
 
 // PushAction appends an action to the controller's actionQueue.
-func (k Keeper) PushAction(ctx sdk.Context, action vm.Jsonable) error {
+func (k Keeper) PushAction(ctx sdk.Context, action vm.Action) error {
 	return k.pushAction(ctx, StoragePathActionQueue, action)
 }
 
 // PushAction appends an action to the controller's highPriorityQueue.
-func (k Keeper) PushHighPriorityAction(ctx sdk.Context, action vm.Jsonable) error {
+func (k Keeper) PushHighPriorityAction(ctx sdk.Context, action vm.Action) error {
 	return k.pushAction(ctx, StoragePathHighPriorityQueue, action)
 }
 
@@ -234,7 +248,11 @@ func (k Keeper) UpdateQueueAllowed(ctx sdk.Context) error {
 // until the response.  It is orthogonal to PushAction, and should only be used
 // by SwingSet to perform block lifecycle events (BEGIN_BLOCK, END_BLOCK,
 // COMMIT_BLOCK).
-func (k Keeper) BlockingSend(ctx sdk.Context, action vm.Jsonable) (string, error) {
+func (k Keeper) BlockingSend(ctx sdk.Context, action vm.Action) (string, error) {
+	action, err := populateAction(ctx, action)
+	if err != nil {
+		return "", err
+	}
 	bz, err := json.Marshal(action)
 	if err != nil {
 		return "", err