dispatching db constructor

db/badgerdb/db.go

@@ -70,6 +70,14 @@ type versionManager struct {
 	lastTs uint64
 }
 
+func init() {
+	creator := func(name string, dir string) (db.DBConnection, error) {
+		dir = filepath.Join(dir, name)
+		return NewDB(dir)
+	}
+	db.RegisterCreator(db.BadgerDBBackend, creator, false)
+}
+
 // NewDB creates or loads a BadgerDB key-value database inside the given directory.
 // If dir does not exist, it will be created.
 func NewDB(dir string) (*BadgerDB, error) {

db/creator.go

@@ -0,0 +1,55 @@
+package db
+
+import (
+	"fmt"
+	"strings"
+)
+
+type BackendType string
+
+// These are valid backend types.
+const (
+	// MemDBBackend represents in-memory key value store, which is mostly used
+	// for testing.
+	MemDBBackend BackendType = "memdb"
+	// RocksDBBackend represents rocksdb (uses github.com/cosmos/gorocksdb)
+	//   - EXPERIMENTAL
+	//   - requires gcc
+	//   - use rocksdb build tag (go build -tags rocksdb)
+	RocksDBBackend BackendType = "rocksdb"
+	// BadgerDBBackend represents BadgerDB
+	//   - pure Go
+	//   - requires badgerdb build tag
+	BadgerDBBackend BackendType = "badgerdb"
+)
+
+type DBCreator func(name string, dir string) (DBConnection, error)
+
+var backends = map[BackendType]DBCreator{}
+
+func RegisterCreator(backend BackendType, creator DBCreator, force bool) {
+	_, ok := backends[backend]
+	if !force && ok {
+		return
+	}
+	backends[backend] = creator
+}
+
+// NewDB creates a new database of type backend with the given name.
+func NewDB(name string, backend BackendType, dir string) (DBConnection, error) {
+	creator, ok := backends[backend]
+	if !ok {
+		keys := make([]string, 0, len(backends))
+		for k := range backends {
+			keys = append(keys, string(k))
+		}
+		return nil, fmt.Errorf("unknown db_backend %s, expected one of %v",
+			backend, strings.Join(keys, ","))
+	}
+
+	db, err := creator(name, dir)
+	if err != nil {
+		return nil, fmt.Errorf("failed to initialize database: %w", err)
+	}
+	return db, nil
+}

db/memdb/db.go

@@ -16,6 +16,13 @@ const (
 	bTreeDegree = 32
 )
 
+func init() {
+	creator := func(name string, dir string) (db.DBConnection, error) {
+		return NewDB(), nil
+	}
+	db.RegisterCreator(db.MemDBBackend, creator, false)
+}
+
 // MemDB is an in-memory database backend using a B-tree for storage.
 //
 // For performance reasons, all given and returned keys and values are pointers to the in-memory

db/rocksdb/db.go

@@ -68,6 +68,14 @@ type dbOptions struct {
 	wo  *gorocksdb.WriteOptions
 }
 
+func init() {
+	creator := func(name string, dir string) (DBConnection, error) {
+		dir = filepath.Join(dir, name)
+		return NewDB(dir)
+	}
+	db.RegisterCreator(db.RocksDBBackend, creator, false)
+}
+
 // NewDB creates a new RocksDB key-value database with inside the given directory.
 // If dir does not exist, it will be created.
 func NewDB(dir string) (*dbManager, error) {

server/constructors_test.go

@@ -6,12 +6,12 @@ import (
 
 	"github.com/stretchr/testify/require"
 
-	dbm "github.com/tendermint/tm-db"
+	dbm "github.com/cosmos/cosmos-sdk/db"
 )
 
 func Test_openDB(t *testing.T) {
 	t.Parallel()
-	_, err := openDB(t.TempDir(), dbm.GoLevelDBBackend)
+	_, err := openDB(t.TempDir(), dbm.BadgerDBBackend)
 	require.NoError(t, err)
 }
 

server/mock/app.go

@@ -9,7 +9,6 @@ import (
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/types"
-	dbm "github.com/tendermint/tm-db"
 
 	bam "github.com/cosmos/cosmos-sdk/baseapp"
 	"github.com/cosmos/cosmos-sdk/codec"

server/util.go

@@ -26,7 +26,6 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/client/flags"
 	dbm "github.com/cosmos/cosmos-sdk/db"
-	"github.com/cosmos/cosmos-sdk/db/badgerdb"
 	"github.com/cosmos/cosmos-sdk/server/config"
 	"github.com/cosmos/cosmos-sdk/server/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
@@ -365,7 +364,7 @@ func GetAppDBBackend(opts types.AppOptions) dbm.BackendType {
 	if len(rv) != 0 {
 		return dbm.BackendType(rv)
 	}
-	return dbm.GoLevelDBBackend
+	return dbm.BadgerDBBackend
 }
 
 func skipInterface(iface net.Interface) bool {
@@ -392,9 +391,9 @@ func addrToIP(addr net.Addr) net.IP {
 	return ip
 }
 
-func openDB(rootDir string) (dbm.DBConnection, error) {
-	dir := filepath.Join(rootDir, "data", "application")
-	return badgerdb.NewDB(dir)
+func openDB(rootDir string, backendType dbm.BackendType) (dbm.DBConnection, error) {
+	dataDir := filepath.Join(rootDir, "data")
+	return dbm.NewDB("application", backendType, dataDir)
 }
 
 func openTraceWriter(traceWriterFile string) (w io.Writer, err error) {

server/util_test.go

@@ -14,10 +14,10 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	tmcfg "github.com/tendermint/tendermint/config"
-	dbm "github.com/tendermint/tm-db"
 
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/client/flags"
+	dbm "github.com/cosmos/cosmos-sdk/db"
 	"github.com/cosmos/cosmos-sdk/server"
 	"github.com/cosmos/cosmos-sdk/server/config"
 	servertypes "github.com/cosmos/cosmos-sdk/server/types"
@@ -466,7 +466,7 @@ func TestGetAppDBBackend(t *testing.T) {
 			name:   "nothing set",
 			dbBack: "",
 			opts:   mapGetter{},
-			exp:    dbm.GoLevelDBBackend,
+			exp:    dbm.BadgerDBBackend,
 		},
 
 		{