WIP: Modular AnteHandler

server/mock/tx.go

@@ -38,6 +38,10 @@ func (tx kvstoreTx) GetMsgs() []sdk.Msg {
 	return []sdk.Msg{tx}
 }
 
+func (tx kvstoreTx) Gas() uint64 {
+	return 0
+}
+
 func (tx kvstoreTx) GetMemo() string {
 	return ""
 }

simapp/sim_test.go

@@ -602,7 +602,7 @@ func testAndRunTxs(app *SimApp) []simulation.WeightedOperation {
 					})
 				return v
 			}(nil),
-			authsim.SimulateDeductFee(app.accountKeeper, app.supplyKeeper),
+			distrsim.SimulateDeductFee(app.accountKeeper, app.supplyKeeper),
 		},
 		{
 			func(_ *rand.Rand) int {

types/module/module.go

@@ -28,6 +28,7 @@ needlessly defining many placeholder functions
 package module
 
 import (
+	"fmt"
 	"encoding/json"
 
 	"github.com/gorilla/mux"
@@ -139,6 +140,7 @@ type AppModule interface {
 	QuerierRoute() string
 	NewQuerierHandler() sdk.Querier
 
+	AnteHandle(sdk.Context, sdk.Tx, bool) (sdk.Context, sdk.Result, bool)
 	BeginBlock(sdk.Context, abci.RequestBeginBlock)
 	EndBlock(sdk.Context, abci.RequestEndBlock) []abci.ValidatorUpdate
 }
@@ -171,6 +173,11 @@ func (GenesisOnlyAppModule) QuerierRoute() string { return "" }
 // module querier
 func (gam GenesisOnlyAppModule) NewQuerierHandler() sdk.Querier { return nil }
 
+// module ante-handle
+func (gam GenesisOnlyAppModule) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool) (newCtx sdk.Context, res sdk.Result, abort bool) {
+	return ctx, sdk.Result{}, false
+} 
+
 // module begin-block
 func (gam GenesisOnlyAppModule) BeginBlock(ctx sdk.Context, req abci.RequestBeginBlock) {}
 
@@ -186,6 +193,7 @@ type Manager struct {
 	Modules            map[string]AppModule
 	OrderInitGenesis   []string
 	OrderExportGenesis []string
+	OrderAnteHandlers  []string
 	OrderBeginBlockers []string
 	OrderEndBlockers   []string
 }
@@ -204,6 +212,7 @@ func NewManager(modules ...AppModule) *Manager {
 		Modules:            moduleMap,
 		OrderInitGenesis:   modulesStr,
 		OrderExportGenesis: modulesStr,
+		OrderAnteHandlers:  modulesStr,
 		OrderBeginBlockers: modulesStr,
 		OrderEndBlockers:   modulesStr,
 	}
@@ -219,6 +228,11 @@ func (m *Manager) SetOrderExportGenesis(moduleNames ...string) {
 	m.OrderExportGenesis = moduleNames
 }
 
+// set the order of module antehandlers
+func (m *Manager) SetOrderAnteHandler(moduleNames ...string) {
+	m.OrderAnteHandlers = moduleNames
+}
+
 // set the order of set begin-blocker calls
 func (m *Manager) SetOrderBeginBlockers(moduleNames ...string) {
 	m.OrderBeginBlockers = moduleNames
@@ -280,6 +294,43 @@ func (m *Manager) ExportGenesis(ctx sdk.Context) map[string]json.RawMessage {
 	return genesisData
 }
 
+// perform antehandle functionality for modules
+func (m *Manager) AnteHandler(ctx sdk.Context, tx sdk.Tx, simulate bool) (newCtx sdk.Context, res sdk.Result, abort bool) {
+	newCtx = sdk.SetGasMeter(simulate, ctx, tx.Gas())
+
+	// AnteHandlers must have their own defer/recover in order for the BaseApp
+	// to know how much gas was used! This is because the GasMeter is created in
+	// the AnteHandler, but if it panics the context won't be set properly in
+	// runTx's recover call.
+	defer func() {
+		if r := recover(); r != nil {
+			switch rType := r.(type) {
+			case sdk.ErrorOutOfGas:
+				log := fmt.Sprintf(
+					"out of gas in location: %v; gasWanted: %d, gasUsed: %d",
+					rType.Descriptor, tx.Gas(), newCtx.GasMeter().GasConsumed(),
+				)
+				res = sdk.ErrOutOfGas(log).Result()
+
+				res.GasWanted = tx.Gas()
+				res.GasUsed = newCtx.GasMeter().GasConsumed()
+				abort = true
+			default:
+				panic(r)
+			}
+		}
+	}()
+
+	// must somehow consume gas cost for validating tx (tx size cost/byte)
+	for _, moduleName := range m.OrderAnteHandlers {
+		newCtx, res, abort = m.Modules[moduleName].AnteHandle(newCtx, tx, simulate)
+		if abort {
+			return newCtx, res, abort
+		}
+	}
+	return newCtx, res, abort
+}
+
 // BeginBlock performs begin block functionality for all modules. It creates a
 // child context with an event manager to aggregate events emitted from all
 // modules.

types/module/test_common.go

@@ -0,0 +1,34 @@
+package module
+
+import (
+	"fmt"
+	"testing"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/stretchr/testify/require"
+)
+
+// run the tx through the anteHandler and ensure its valid
+func CheckValidTx(t *testing.T, m Manager, ctx sdk.Context, tx sdk.Tx, simulate bool) {
+	_, result, abort := m.AnteHandler(ctx, tx, simulate)
+	require.Equal(t, "", result.Log)
+	require.False(t, abort)
+	require.Equal(t, sdk.CodeOK, result.Code)
+	require.True(t, result.IsOK())
+}
+
+// run the tx through the anteHandler and ensure it fails with the given code
+func CheckInvalidTx(t *testing.T, m Manager, ctx sdk.Context, tx sdk.Tx, simulate bool, code sdk.CodeType) {
+	newCtx, result, abort := m.AnteHandler(ctx, tx, simulate)
+	require.True(t, abort)
+
+	require.Equal(t, code, result.Code, fmt.Sprintf("Expected %v, got %v", code, result))
+	require.Equal(t, sdk.CodespaceRoot, result.Codespace)
+
+	if code == sdk.CodeOutOfGas {
+		// GasWanted set correctly
+		require.Equal(t, tx.Gas(), result.GasWanted, "Gas wanted not set correctly")
+		require.True(t, result.GasUsed > result.GasWanted, "GasUsed not greated than GasWanted")
+		// Check that context is set correctly
+		require.Equal(t, result.GasUsed, newCtx.GasMeter().GasConsumed(), "Context not updated correctly")
+	}
+}

types/store.go

@@ -128,3 +128,14 @@ type (
 func NewInfiniteGasMeter() GasMeter {
 	return types.NewInfiniteGasMeter()
 }
+
+// SetGasMeter returns a new context with a gas meter set from a given context.
+func SetGasMeter(simulate bool, ctx Context, gasLimit uint64) Context {
+	// In various cases such as simulation and during the genesis block, we do not
+	// meter any gas utilization.
+	if simulate || ctx.BlockHeight() == 0 {
+		return ctx.WithGasMeter(NewInfiniteGasMeter())
+	}
+
+	return ctx.WithGasMeter(NewGasMeter(gasLimit))
+}

types/tx_msg.go

@@ -38,6 +38,11 @@ type Tx interface {
 	// ValidateBasic does a simple and lightweight validation check that doesn't
 	// require access to any other information.
 	ValidateBasic() Error
+
+	// Gas returns the amount of Gas this tx is allowed to consume
+	Gas() uint64
+
+	FeeCoins() []Coin
 }
 
 //__________________________________________________________

x/auth/alias.go

@@ -12,7 +12,6 @@ import (
 const (
 	ModuleName                    = types.ModuleName
 	StoreKey                      = types.StoreKey
-	FeeCollectorName              = types.FeeCollectorName
 	QuerierRoute                  = types.QuerierRoute
 	DefaultParamspace             = types.DefaultParamspace
 	DefaultMaxMemoCharacters      = types.DefaultMaxMemoCharacters