cli: allow node operator to rollback last state (backport #7033) (#7080)

cmd/tendermint/commands/rollback.go

@@ -0,0 +1,69 @@
+package commands
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+
+	dbm "github.com/tendermint/tm-db"
+
+	cfg "github.com/tendermint/tendermint/config"
+	"github.com/tendermint/tendermint/state"
+	"github.com/tendermint/tendermint/store"
+)
+
+var RollbackStateCmd = &cobra.Command{
+	Use:   "rollback",
+	Short: "rollback tendermint state by one height",
+	Long: `
+A state rollback is performed to recover from an incorrect application state transition,
+when Tendermint has persisted an incorrect app hash and is thus unable to make
+progress. Rollback overwrites a state at height n with the state at height n - 1.
+The application should also roll back to height n - 1. No blocks are removed, so upon
+restarting Tendermint the transactions in block n will be re-executed against the
+application.
+`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		height, hash, err := RollbackState(config)
+		if err != nil {
+			return fmt.Errorf("failed to rollback state: %w", err)
+		}
+
+		fmt.Printf("Rolled back state to height %d and hash %v", height, hash)
+		return nil
+	},
+}
+
+// RollbackState takes the state at the current height n and overwrites it with the state
+// at height n - 1. Note state here refers to tendermint state not application state.
+// Returns the latest state height and app hash alongside an error if there was one.
+func RollbackState(config *cfg.Config) (int64, []byte, error) {
+	// use the parsed config to load the block and state store
+	blockStore, stateStore, err := loadStateAndBlockStore(config)
+	if err != nil {
+		return -1, nil, err
+	}
+
+	// rollback the last state
+	return state.Rollback(blockStore, stateStore)
+}
+
+func loadStateAndBlockStore(config *cfg.Config) (*store.BlockStore, state.Store, error) {
+	dbType := dbm.BackendType(config.DBBackend)
+
+	// Get BlockStore
+	blockStoreDB, err := dbm.NewDB("blockstore", dbType, config.DBDir())
+	if err != nil {
+		return nil, nil, err
+	}
+	blockStore := store.NewBlockStore(blockStoreDB)
+
+	// Get StateStore
+	stateDB, err := dbm.NewDB("state", dbType, config.DBDir())
+	if err != nil {
+		return nil, nil, err
+	}
+	stateStore := state.NewStore(stateDB)
+
+	return blockStore, stateStore, nil
+}

cmd/tendermint/main.go

@@ -27,6 +27,7 @@ func main() {
 		cmd.ShowNodeIDCmd,
 		cmd.GenNodeKeyCmd,
 		cmd.VersionCmd,
+		cmd.RollbackStateCmd,
 		debug.DebugCmd,
 		cli.NewCompletionCmd(rootCmd, true),
 	)