FerretDB · AlekSi · Aug 25, 2023 · Aug 25, 2023 · Aug 25, 2023 · Aug 25, 2023
@@ -28,8 +28,9 @@
 // The following Go build tags (also known as build constraints) affect all builds of FerretDB,
 // including embedded usage:
 //
-//	ferretdb_debug     - enables debug build (see below; implied by builds with race detector)
-//	ferretdb_hana      - enables Hana backend handler (alpha)
+//	ferretdb_debug - enables debug build (see below; implied by builds with race detector)
+//	ferretdb_hana  - enables Hana backend (alpha)
+//	ferretdb_newpg - replaces PostgreSQL backend with a new version (alpha)
 //
 // # Debug builds
 //

@@ -0,0 +1,76 @@
+// 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 postgresql
+
+import (
+	"context"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"go.uber.org/zap"
+
+	"github.com/FerretDB/FerretDB/internal/backends"
+)
+
+// backend implements backends.Backend interface.
+type backend struct{}
+
+// NewBackendParams represents the parameters of NewBackend function.
+//
+//nolint:vet // for readability
+type NewBackendParams struct {
+	URI string
+	L   *zap.Logger
+}
+
+// NewBackend creates a new backend for PostgreSQL-compatible database.
+func NewBackend(params *NewBackendParams) (backends.Backend, error) {
+	return backends.BackendContract(new(backend)), nil
+}
+
+// Close implements backends.Backend interface.
+func (b *backend) Close() {
+}
+
+// Database implements backends.Backend interface.
+func (b *backend) Database(name string) (backends.Database, error) {
+	return newDatabase(name), nil
+}
+
+// ListDatabases implements backends.Backend interface.
+//
+//nolint:lll // for readability
+func (b *backend) ListDatabases(ctx context.Context, params *backends.ListDatabasesParams) (*backends.ListDatabasesResult, error) {
+	panic("not implemented")
+}
+
+// DropDatabase implements backends.Backend interface.
+func (b *backend) DropDatabase(ctx context.Context, params *backends.DropDatabaseParams) error {
+	panic("not implemented")
+}
+
+// Describe implements prometheus.Collector.
+func (b *backend) Describe(ch chan<- *prometheus.Desc) {
+	panic("not implemented")
+}
+
+// Collect implements prometheus.Collector.
+func (b *backend) Collect(ch chan<- prometheus.Metric) {
+	panic("not implemented")
+}
+
+// check interfaces
+var (
+	_ backends.Backend = (*backend)(nil)
+)
@@ -0,0 +1,65 @@
+// 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 postgresql
+
+import (
+	"context"
+
+	"github.com/FerretDB/FerretDB/internal/backends"
+)
+
+// collection implements backends.Collection interface.
+type collection struct {
+	dbName string
+	name   string
+}
+
+// newCollection creates a new Collection.
+func newCollection(dbName, name string) backends.Collection {
+	return backends.CollectionContract(&collection{
+		dbName: dbName,
+		name:   name,
+	})
+}
+
+// Query implements backends.Collection interface.
+func (c *collection) Query(ctx context.Context, params *backends.QueryParams) (*backends.QueryResult, error) {
+	panic("not implemented")
+}
+
+// Insert implements backends.Collection interface.
+func (c *collection) Insert(ctx context.Context, params *backends.InsertParams) (*backends.InsertResult, error) {
+	panic("not implemented")
+}
+
+// Update implements backends.Collection interface.
+func (c *collection) Update(ctx context.Context, params *backends.UpdateParams) (*backends.UpdateResult, error) {
+	panic("not implemented")
+}
+
+// Delete implements backends.Collection interface.
+func (c *collection) Delete(ctx context.Context, params *backends.DeleteParams) (*backends.DeleteResult, error) {
+	panic("not implemented")
+}
+
+// Explain implements backends.Collection interface.
+func (c *collection) Explain(ctx context.Context, params *backends.ExplainParams) (*backends.ExplainResult, error) {
+	panic("not implemented")
+}
+
+// check interfaces
+var (
+	_ backends.Collection = (*collection)(nil)
+)
@@ -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 postgresql
+
+import (
+	"context"
+
+	"github.com/FerretDB/FerretDB/internal/backends"
+)
+
+// database implements backends.Database interface.
+type database struct {
+	name string
+}
+
+// newDatabase creates a new Database.
+func newDatabase(name string) backends.Database {
+	return backends.DatabaseContract(&database{
+		name: name,
+	})
+}
+
+// Close implements backends.Database interface.
+func (db *database) Close() {
+	// nothing
+}
+
+// Collection implements backends.Database interface.
+func (db *database) Collection(name string) (backends.Collection, error) {
+	return newCollection(db.name, name), nil
+}
+
+// ListCollections implements backends.Database interface.
+//
+//nolint:lll // for readability
+func (db *database) ListCollections(ctx context.Context, params *backends.ListCollectionsParams) (*backends.ListCollectionsResult, error) {
+	panic("not implemented")
+}
+
+// CreateCollection implements backends.Database interface.
+func (db *database) CreateCollection(ctx context.Context, params *backends.CreateCollectionParams) error {
+	panic("not implemented")
+}
+
+// DropCollection implements backends.Database interface.
+func (db *database) DropCollection(ctx context.Context, params *backends.DropCollectionParams) error {
+	panic("not implemented")
+}
+
+// RenameCollection implements backends.Database interface.
+func (db *database) RenameCollection(ctx context.Context, params *backends.RenameCollectionParams) error {
+	panic("not implemented")
+}
+
+// check interfaces
+var (
+	_ backends.Database = (*database)(nil)
+)
@@ -0,0 +1,16 @@
+// 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 postgresql provides backend for PostgreSQL and compatible databases.
+package postgresql
@@ -30,6 +30,8 @@ type backend struct {
 }
 
 // NewBackendParams represents the parameters of NewBackend function.
+//
+//nolint:vet // for readability
 type NewBackendParams struct {
 	URI string
 	L   *zap.Logger

@@ -0,0 +1,42 @@
+// 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.
+
+//go:build ferretdb_newpg
+
+package registry
+
+import (
+	"github.com/FerretDB/FerretDB/internal/handlers"
+	"github.com/FerretDB/FerretDB/internal/handlers/sqlite"
+)
+
+// init registers new "pg" handler.
+func init() {
+	registry["pg"] = func(opts *NewHandlerOpts) (handlers.Interface, error) {
+		opts.Logger.Warn("New PostgreSQL backend is in alpha.")
+
+		handlerOpts := &sqlite.NewOpts{
+			Backend: "postgresql",
+			URI:     opts.PostgreSQLURL,
+
+			L:             opts.Logger.Named("postgresql"),
+			ConnMetrics:   opts.ConnMetrics,
+			StateProvider: opts.StateProvider,
+
+			DisableFilterPushdown: opts.DisableFilterPushdown,
+		}
+
+		return sqlite.New(handlerOpts)
+	}
+}
@@ -12,14 +12,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !ferretdb_newpg
+
 package registry
 
 import (
 	"github.com/FerretDB/FerretDB/internal/handlers"
 	"github.com/FerretDB/FerretDB/internal/handlers/pg"
 )
 
-// init registers "pg" handler.
+// init registers old "pg" handler.
 func init() {
 	registry["pg"] = func(opts *NewHandlerOpts) (handlers.Interface, error) {
 		handlerOpts := &pg.NewOpts{

@@ -86,5 +86,9 @@ func Handlers() []string {
 		res = append(res, h)
 	}
 
+	if len(res) != len(registry) {
+		panic("registry is not in sync")
+	}
+
 	return res
 }
@@ -22,10 +22,11 @@ import (
 // init registers "sqlite" handler.
 func init() {
 	registry["sqlite"] = func(opts *NewHandlerOpts) (handlers.Interface, error) {
-		opts.Logger.Warn("SQLite handler is in beta.")
+		opts.Logger.Warn("SQLite backend is in beta.")
 
 		handlerOpts := &sqlite.NewOpts{
-			URI: opts.SQLiteURL,
+			Backend: "sqlite",
+			URI:     opts.SQLiteURL,
 
 			L:             opts.Logger.Named("sqlite"),
 			ConnMetrics:   opts.ConnMetrics,

@@ -22,6 +22,7 @@ import (
 	"go.uber.org/zap"
 
 	"github.com/FerretDB/FerretDB/internal/backends"
+	"github.com/FerretDB/FerretDB/internal/backends/postgresql"
 	"github.com/FerretDB/FerretDB/internal/backends/sqlite"
 	"github.com/FerretDB/FerretDB/internal/clientconn/connmetrics"
 	"github.com/FerretDB/FerretDB/internal/clientconn/cursor"
@@ -51,7 +52,8 @@ type Handler struct {
 //
 //nolint:vet // for readability
 type NewOpts struct {
-	URI string
+	Backend string
+	URI     string
 
 	L             *zap.Logger
 	ConnMetrics   *connmetrics.ConnMetrics
@@ -63,10 +65,24 @@ type NewOpts struct {
 
 // New returns a new handler.
 func New(opts *NewOpts) (handlers.Interface, error) {
-	b, err := sqlite.NewBackend(&sqlite.NewBackendParams{
-		URI: opts.URI,
-		L:   opts.L,
-	})
+	var b backends.Backend
+	var err error
+
+	switch opts.Backend {
+	case "postgresql":
+		b, err = postgresql.NewBackend(&postgresql.NewBackendParams{
+			URI: opts.URI,
+			L:   opts.L,
+		})
+	case "sqlite":
+		b, err = sqlite.NewBackend(&sqlite.NewBackendParams{
+			URI: opts.URI,
+			L:   opts.L,
+		})
+	default:
+		panic("unknown backend: " + opts.Backend)
+	}
+
 	if err != nil {
 		return nil, err
 	}