WIP

FerretDB · AlekSi · May 18, 2023 · May 16, 2023 · May 16, 2023 · May 16, 2023
commit f9dbb259eead9c37333233fe7168c4de4a46f0e5
@@ -24,7 +24,8 @@ import (
 
 // backend implements backends.Backend interface.
 type backend struct {
-	dir string
+	dir             string
+	metadataStorage *metadataStorage
 }
 
 // NewBackendParams represents the parameters of NewBackend function.
@@ -33,10 +34,19 @@ type NewBackendParams struct {
 }
 
 // NewBackend creates a new SQLite backend.
-func NewBackend(params *NewBackendParams) backends.Backend {
+func NewBackend(params *NewBackendParams) (backends.Backend, error) {
+	// TODO: we should close it when backend is closed.
+	pool := newConnPool()
+
+	storage, err := newMetadataStorage(params.Dir, pool)
+	if err != nil {
+		return nil, err
+	}
+
 	return backends.BackendContract(&backend{
-		dir: params.Dir,
-	})
+		dir:             params.Dir,
+		metadataStorage: storage,
+	}), nil
 }
 
 // Database implements backends.Backend interface.

@@ -1,3 +1,17 @@
+// Copyright 2021 FerretDB Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package sqlite
 
 import (
@@ -16,7 +30,6 @@ import (
 )
 
 const (
-
 	// Reserved prefix for database and collection names.
 	reservedPrefix = "_ferretdb_"
 
@@ -27,14 +40,13 @@ const (
 )
 
 // newMetadataStorage returns instance of metadata storage.
-func newMetadataStorage(dbPath string) (*metadataStorage, error) {
+func newMetadataStorage(dbPath string, pool *connPool) (*metadataStorage, error) {
 	if dbPath == "" {
 		return nil, errors.New("db path is empty")
 	}
 
 	return &metadataStorage{
-		// TODO: might be passed as parameter.
-		connPool: newConnPool(),
+		connPool: pool,
 		dbPath:   dbPath,
 		dbs:      make(map[string]*dbInfo),
 	}, nil
@@ -131,7 +143,7 @@ func (m *metadataStorage) RemoveDatabase(database string) error {
 }
 
 // RemoveCollection removes collection metadata.
-// It does not physically remove collection from database.
+// It does not remove collection from database.
 func (m *metadataStorage) RemoveCollection(database, collection string) error {
 	m.mx.Lock()
 	defer m.mx.Unlock()
@@ -151,6 +163,8 @@ func (m *metadataStorage) RemoveCollection(database, collection string) error {
 	return nil
 }
 
+// CreateDatabase adds database to metadata storage.
+// It doesn't create database file.
 func (m *metadataStorage) CreateDatabase(database string) error {
 	m.mx.Lock()
 	defer m.mx.Unlock()
@@ -165,7 +179,7 @@ func (m *metadataStorage) CreateDatabase(database string) error {
 	return nil
 }
 
-// CreateCollection saves collection metadata to database file
+// CreateCollection saves collection metadata to database file.
 func (m *metadataStorage) CreateCollection(ctx context.Context, database, collection string) error {
 	m.mx.Lock()
 	defer m.mx.Unlock()
@@ -180,7 +194,7 @@ func (m *metadataStorage) CreateCollection(ctx context.Context, database, collec
 		return errors.New("collection already exists")
 	}
 
-	tableName := mangleCollection(collection)
+	tableName := tableNameFromCollectionName(collection)
 
 	err := m.saveCollection(ctx, database, collection, tableName)
 	if err != nil {
@@ -257,8 +271,8 @@ func (m *metadataStorage) saveCollection(ctx context.Context, dbName, collName,
 	return nil
 }
 
-// mangleCollection mangles collection name to table name.
+// tableNameFromCollectionName mangles collection name to table name.
 // TODO: implement proper mangle if needed.
-func mangleCollection(name string) string {
+func tableNameFromCollectionName(name string) string {
 	return name
 }
@@ -0,0 +1,70 @@
+// Copyright 2021 FerretDB Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sqlite
+
+import (
+	"database/sql"
+	"errors"
+	"sync"
+)
+
+// newConnPool creates a new connection pool.
+func newConnPool() *connPool {
+	return &connPool{
+		mx:  sync.Mutex{},
+		dbs: make(map[string]*sql.DB),
+	}
+}
+
+// connPool is a pool of database connections.
+type connPool struct {
+	mx  sync.Mutex
+	dbs map[string]*sql.DB
+}
+
+// DB returns a database connection for the given name.
+func (c *connPool) DB(name string) (*sql.DB, error) {
+	c.mx.Lock()
+	defer c.mx.Unlock()
+
+	if db, ok := c.dbs[name]; ok {
+		return db, nil
+	}
+
+	db, err := sql.Open("sqlite", name)
+	if err != nil {
+		return nil, err
+	}
+
+	c.dbs[name] = db
+
+	return db, nil
+}
+
+// Close closes all database connections.
+func (c *connPool) Close() error {
+	var errs error
+
+	c.mx.Lock()
+	defer c.mx.Unlock()
+
+	for _, conn := range c.dbs {
+		if err := conn.Close(); err != nil {
+			errors.Join(err)
+		}
+	}
+
+	return errs
+}
diff --git a/internal/handlers/sqlite/pool.go b/internal/handlers/sqlite/pool.go
@@ -51,9 +51,12 @@ type NewOpts struct {
 
 // New returns a new handler.
 func New(opts *NewOpts) (handlers.Interface, error) {
-	b := sqlite.NewBackend(&sqlite.NewBackendParams{
+	b, err := sqlite.NewBackend(&sqlite.NewBackendParams{
 		Dir: opts.Dir,
 	})
+	if err != nil {
+		return nil, err
+	}
 
 	return &Handler{
 		NewOpts: opts,