Add version file to database (#1678)

* Add version file to database

* Remove redundant code

* Check for version before opening the database, create version file after

* Create version file before opening the database

app/app.go

@@ -85,12 +85,6 @@ func (app *kaspadApp) main(startedChan chan<- struct{}) error {
 		profiling.Start(app.cfg.Profile, log)
 	}
 
-	// Perform upgrades to kaspad as new versions require it.
-	if err := doUpgrades(); err != nil {
-		log.Error(err)
-		return err
-	}
-
 	// Return now if an interrupt signal was triggered.
 	if signal.InterruptRequested(interrupt) {
 		return nil
@@ -163,12 +157,6 @@ func (app *kaspadApp) main(startedChan chan<- struct{}) error {
 	return nil
 }
 
-// doUpgrades performs upgrades to kaspad as new versions require it.
-// currently it's a placeholder we got from kaspad upstream, that does nothing
-func doUpgrades() error {
-	return nil
-}
-
 // dbPath returns the path to the block database given a database type.
 func databasePath(cfg *config.Config) string {
 	return filepath.Join(cfg.AppDir, "data")
@@ -181,6 +169,17 @@ func removeDatabase(cfg *config.Config) error {
 
 func openDB(cfg *config.Config) (database.Database, error) {
 	dbPath := databasePath(cfg)
+
+	err := checkDatabaseVersion(dbPath)
+	if err != nil {
+		return nil, err
+	}
+
 	log.Infof("Loading database from '%s'", dbPath)
-	return ldb.NewLevelDB(dbPath, leveldbCacheSizeMiB)
+	db, err := ldb.NewLevelDB(dbPath, leveldbCacheSizeMiB)
+	if err != nil {
+		return nil, err
+	}
+
+	return db, nil
 }

app/db_version.go

@@ -0,0 +1,57 @@
+package app
+
+import (
+	"os"
+	"path"
+	"strconv"
+
+	"github.com/pkg/errors"
+)
+
+const currentDatabaseVersion = 1
+
+func checkDatabaseVersion(dbPath string) (err error) {
+	versionFileName := versionFilePath(dbPath)
+
+	versionBytes, err := os.ReadFile(versionFileName)
+	if err != nil {
+		if os.IsNotExist(err) { // If version file doesn't exist, we assume that the database is new
+			return createDatabaseVersionFile(dbPath, versionFileName)
+		}
+		return err
+	}
+
+	databaseVersion, err := strconv.Atoi(string(versionBytes))
+	if err != nil {
+		return err
+	}
+
+	if databaseVersion != currentDatabaseVersion {
+		// TODO: Once there's more then one database version, it might make sense to add upgrade logic at this point
+		return errors.Errorf("Invalid database version %d. Expected version: %d", databaseVersion, currentDatabaseVersion)
+	}
+
+	return nil
+}
+
+func createDatabaseVersionFile(dbPath string, versionFileName string) error {
+	err := os.MkdirAll(dbPath, 0700)
+	if err != nil {
+		return err
+	}
+
+	versionFile, err := os.Create(versionFileName)
+	if err != nil {
+		return nil
+	}
+	defer versionFile.Close()
+
+	versionString := strconv.Itoa(currentDatabaseVersion)
+	_, err = versionFile.Write([]byte(versionString))
+	return err
+}
+
+func versionFilePath(dbPath string) string {
+	dbVersionFileName := path.Join(dbPath, "version")
+	return dbVersionFileName
+}

domain/consensus/processes/consensusstatemanager/add_block_to_virtual.go

@@ -9,7 +9,9 @@ import (
 // AddBlock submits the given block to be added to the
 // current virtual. This process may result in a new virtual block
 // getting created
-func (csm *consensusStateManager) AddBlock(stagingArea *model.StagingArea, blockHash *externalapi.DomainHash) (*externalapi.SelectedChainPath, externalapi.UTXODiff, error) {
+func (csm *consensusStateManager) AddBlock(stagingArea *model.StagingArea, blockHash *externalapi.DomainHash) (
+	*externalapi.SelectedChainPath, externalapi.UTXODiff, error) {
+
 	onEnd := logger.LogAndMeasureExecutionTime(log, "csm.AddBlock")
 	defer onEnd()