Add MySQL backend registry

.golangci.yml

@@ -144,6 +144,8 @@ linters-settings:
         alias: otelsdktrace
       - pkg: go.opentelemetry.io/otel/semconv/v1.21.0
         alias: otelsemconv
+      - pkg: github.com/FerretDB/FerretDB/internal/backends/mysql/metadata/pool
+        alias: mysqlpool
   # ineffassign
   lll:
     line-length: 130

cmd/envtool/envtool.go

@@ -38,6 +38,7 @@ import (
 	"go.uber.org/zap/zapcore"
 
 	"github.com/FerretDB/FerretDB/build/version"
+	mysqlpool "github.com/FerretDB/FerretDB/internal/backends/mysql/metadata/pool"
 	"github.com/FerretDB/FerretDB/internal/backends/postgresql/metadata/pool"
 	"github.com/FerretDB/FerretDB/internal/util/ctxutil"
 	"github.com/FerretDB/FerretDB/internal/util/debug"
@@ -147,32 +148,45 @@ func setupPostgresSecured(ctx context.Context, logger *zap.SugaredLogger) error
 
 // setupMySQL configures `mysql` container.
 func setupMySQL(ctx context.Context, logger *zap.SugaredLogger) error {
+	uri := "mysql://root:password@127.0.0.1:3306/ferretdb"
+
+	sp, err := state.NewProvider("")
+	if err != nil {
+		return err
+	}
+
 	if err := waitForPort(ctx, logger.Named("mysql"), 3306); err != nil {
 		return err
 	}
 
-	// we should replace with backend code similar to setupAnyPostgres
-	eval := "mysql -u root -ppassword -e \"GRANT ALL PRIVILEGES ON *.* TO 'username'@'%';\""
-	args := []string{"compose", "exec", "-T", "mysql", "bash", "-c", eval}
+	p, err := mysqlpool.New(uri, logger.Desugar(), sp)
+	if err != nil {
+		return err
+	}
 
-	var buf bytes.Buffer
-	var retry int64
+	defer p.Close()
 
+	var retry int64
 	for ctx.Err() == nil {
-		buf.Reset()
-
-		err := runCommand("docker", args, &buf, logger)
+		db, err := p.Get("root", "password")
 		if err == nil {
+			if _, rowErr := db.QueryContext(ctx, "GRANT ALL PRIVILEGES ON *.* TO 'username'@'%';"); rowErr != nil {
+				return lazyerrors.Error(err)
+			}
 			break
 		}
 
-		logger.Infof("%s:\n%s", err, buf.String())
+		logger.Infof("%s: %s", uri, err)
 
 		retry++
 		ctxutil.SleepWithJitter(ctx, time.Second, retry)
 	}
 
-	return ctx.Err()
+	if ctx.Err() != nil {
+		return ctx.Err()
+	}
+
+	return nil
 }
 
 // setupMongodb configures `mongodb` container.

internal/backends/mysql/metadata/indexes.go

@@ -16,6 +16,7 @@
 
 import (
 	"errors"
+	"slices"
 
 	"github.com/FerretDB/FerretDB/internal/types"
 	"github.com/FerretDB/FerretDB/internal/util/iterator"
@@ -40,6 +41,22 @@
 	Descending bool
 }
 
+// deepCopy returns a deep copy.
+func (indexes Indexes) deepCopy() Indexes {
+	res := make(Indexes, len(indexes))
+
+	for i, index := range indexes {
+		res[i] = IndexInfo{
+			Name:   index.Name,
+			Index:  index.Index,
+			Key:    slices.Clone(index.Key),
+			Unique: index.Unique,
+		}
+	}
+
+	return res
+}
+
 // marshal returns [*types.Array] for indexes.
 func (indexes Indexes) marshal() *types.Array {
 	res := types.MakeArray(len(indexes))

internal/backends/mysql/metadata/metadata.go

@@ -19,12 +19,27 @@
 	"database/sql"
 	"database/sql/driver"
 
+	"github.com/FerretDB/FerretDB/internal/backends"
 	"github.com/FerretDB/FerretDB/internal/handler/sjson"
 	"github.com/FerretDB/FerretDB/internal/types"
 	"github.com/FerretDB/FerretDB/internal/util/lazyerrors"
 	"github.com/FerretDB/FerretDB/internal/util/must"
 )
 
+const (
+	// DefaultColumn is a column name for all fields.
+	DefaultColumn = backends.ReservedPrefix + "sjson"
+
+	// IDColumn is a MySQL path expression for _id field.
+	IDColumn = DefaultColumn + "->'$._id'"
+
+	// TableIdxColumn is a column name for MySQL generated column.
+	TableIdxColumn = DefaultColumn + "_table"
+
+	// RecordIDColumn is a name for RecordID column to store capped collection record id.
+	RecordIDColumn = backends.ReservedPrefix + "record_id"
+)
+
 // Collection represents collection metadata.
 //
 // Collection value should be immutable to avoid data races.
@@ -37,6 +52,21 @@
 	CappedDocuments int64
 }
 
+// deepCopy returns a deep copy.
+func (c *Collection) deepCopy() *Collection {
+	if c == nil {
+		return nil
+	}
+
+	return &Collection{
+		Name:            c.Name,
+		TableName:       c.TableName,
+		Indexes:         c.Indexes.deepCopy(),
+		CappedSize:      c.CappedSize,
+		CappedDocuments: c.CappedDocuments,
+	}
+}
+
 // Capped returns true if collection is capped.
 func (c Collection) Capped() bool {
 	return c.CappedSize > 0

internal/backends/mysql/metadata/pool/pool.go

@@ -52,7 +52,23 @@
 
 // New creates a new Pool.
 func New(u string, l *zap.Logger, sp *state.Provider) (*Pool, error) {
-	return nil, lazyerrors.New("not yet implemented")
+	baseURI, err := url.Parse(u)
+	if err != nil {
+		return nil, lazyerrors.Error(err)
+	}
+
+	p := &Pool{
+		baseURI: *baseURI,
+		l:       l,
+		sp:      sp,
+		rw:      sync.RWMutex{},
+		dbs:     map[string]*fsql.DB{},
+		token:   resource.NewToken(),
+	}
+
+	resource.Track(p, p.token)
+
+	return p, nil
 }
 
 // Close closes all connections in the pool.
@@ -98,7 +114,7 @@
 	p.rw.Lock()
 	defer p.rw.Unlock()
 
-	// a concurrent connectio might have created a pool already; check again
+	// a concurrent connection might have created a pool already; check again
 	if res = p.dbs[u]; res != nil {
 		p.l.Debug("Pool: found existing pool (after acquiring lock)", zap.String("username", username))
 		return res, nil
@@ -116,6 +132,22 @@
 	return res, nil
 }
 
+// GetAny returns a random open pool of connections to MySQL, or nil if none are available.
+func (p *Pool) GetAny() *fsql.DB {
+	p.rw.RLock()
+	defer p.rw.RUnlock()
+
+	for _, db := range p.dbs {
+		p.l.Debug("Pool.GetAny: return existing pool")
+
+		return db
+	}
+
+	p.l.Debug("Pool.GetAny: no existing pools")
+
+	return nil
+}
+
 // Describe implements Prometheus.Collector.
 func (p *Pool) Describe(ch chan<- *prometheus.Desc) {
 	prometheus.DescribeByCollect(p, ch)

internal/backends/mysql/metadata/pool/uri.go

@@ -16,7 +16,7 @@ package pool
 
 import (
 	"net/url"
-	"path"
+	"strings"
 
 	"github.com/go-sql-driver/mysql"
 )
@@ -36,8 +36,6 @@ func parseURI(uri string) (string, error) {
 	username := u.User.Username()
 	password, _ := u.User.Password()
 
-	dbName := path.Clean(u.Path)
-
 	values := u.Query()
 	params := make(map[string]string, len(values))
 
@@ -52,7 +50,7 @@ func parseURI(uri string) (string, error) {
 		Passwd: password,
 		Net:    "tcp",
 		Addr:   u.Host,
-		DBName: dbName,
+		DBName: strings.TrimPrefix(u.Path, "/"),
 		Params: params,
 	}
 	mysqlURL := cfg.FormatDSN()