gotosocial/internal/db/bundb/drivers.go

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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package bundb
import (
"context"
"database/sql"
"database/sql/driver"
"time"
_ "unsafe" // linkname shenanigans
pgx "github.com/jackc/pgx/v5/stdlib"
"github.com/superseriousbusiness/gotosocial/internal/db"
"github.com/superseriousbusiness/gotosocial/internal/gtserror"
"modernc.org/sqlite"
)
var (
// global SQL driver instances.
postgresDriver = pgx.GetDefaultDriver()
sqliteDriver = getSQLiteDriver()
// check the postgres connection
// conforms to our conn{} interface.
// (note SQLite doesn't export their
// conn type, and gets checked in
// tests very regularly anywho).
_ conn = (*pgx.Conn)(nil)
)
//go:linkname getSQLiteDriver modernc.org/sqlite.newDriver
func getSQLiteDriver() *sqlite.Driver
func init() {
sql.Register("pgx-gts", &PostgreSQLDriver{})
sql.Register("sqlite-gts", &SQLiteDriver{})
}
// PostgreSQLDriver is our own wrapper around the
// pgx/stdlib.Driver{} type in order to wrap further
// SQL driver types with our own err processing.
type PostgreSQLDriver struct{}
func (d *PostgreSQLDriver) Open(name string) (driver.Conn, error) {
c, err := postgresDriver.Open(name)
if err != nil {
return nil, err
}
return &PostgreSQLConn{conn: c.(conn)}, nil
}
type PostgreSQLConn struct{ conn }
func (c *PostgreSQLConn) Begin() (driver.Tx, error) {
return c.BeginTx(context.Background(), driver.TxOptions{})
}
func (c *PostgreSQLConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
tx, err := c.conn.BeginTx(ctx, opts)
err = processPostgresError(err)
if err != nil {
return nil, err
}
return &PostgreSQLTx{tx}, nil
}
func (c *PostgreSQLConn) Prepare(query string) (driver.Stmt, error) {
return c.PrepareContext(context.Background(), query)
}
func (c *PostgreSQLConn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
st, err := c.conn.PrepareContext(ctx, query)
err = processPostgresError(err)
if err != nil {
return nil, err
}
return &PostgreSQLStmt{stmt: st.(stmt)}, nil
}
func (c *PostgreSQLConn) Exec(query string, args []driver.Value) (driver.Result, error) {
return c.ExecContext(context.Background(), query, toNamedValues(args))
}
func (c *PostgreSQLConn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
result, err := c.conn.ExecContext(ctx, query, args)
err = processPostgresError(err)
return result, err
}
func (c *PostgreSQLConn) Query(query string, args []driver.Value) (driver.Rows, error) {
return c.QueryContext(context.Background(), query, toNamedValues(args))
}
func (c *PostgreSQLConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
rows, err := c.conn.QueryContext(ctx, query, args)
err = processPostgresError(err)
return rows, err
}
func (c *PostgreSQLConn) Close() error {
return c.conn.Close()
}
type PostgreSQLTx struct{ driver.Tx }
func (tx *PostgreSQLTx) Commit() error {
err := tx.Tx.Commit()
return processPostgresError(err)
}
func (tx *PostgreSQLTx) Rollback() error {
err := tx.Tx.Rollback()
return processPostgresError(err)
}
type PostgreSQLStmt struct{ stmt }
func (stmt *PostgreSQLStmt) Exec(args []driver.Value) (driver.Result, error) {
return stmt.ExecContext(context.Background(), toNamedValues(args))
}
func (stmt *PostgreSQLStmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
res, err := stmt.stmt.ExecContext(ctx, args)
err = processSQLiteError(err)
return res, err
}
func (stmt *PostgreSQLStmt) Query(args []driver.Value) (driver.Rows, error) {
return stmt.QueryContext(context.Background(), toNamedValues(args))
}
func (stmt *PostgreSQLStmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
rows, err := stmt.stmt.QueryContext(ctx, args)
err = processSQLiteError(err)
return rows, err
}
// SQLiteDriver is our own wrapper around the
// sqlite.Driver{} type in order to wrap further
// SQL driver types with our own functionality,
// e.g. hooks, retries and err processing.
type SQLiteDriver struct{}
func (d *SQLiteDriver) Open(name string) (driver.Conn, error) {
c, err := sqliteDriver.Open(name)
if err != nil {
return nil, err
}
return &SQLiteConn{conn: c.(conn)}, nil
}
type SQLiteConn struct{ conn }
func (c *SQLiteConn) Begin() (driver.Tx, error) {
return c.BeginTx(context.Background(), driver.TxOptions{})
}
func (c *SQLiteConn) BeginTx(ctx context.Context, opts driver.TxOptions) (tx driver.Tx, err error) {
err = retryOnBusy(ctx, func() error {
tx, err = c.conn.BeginTx(ctx, opts)
err = processSQLiteError(err)
return err
})
if err != nil {
return nil, err
}
return &SQLiteTx{Context: ctx, Tx: tx}, nil
}
func (c *SQLiteConn) Prepare(query string) (driver.Stmt, error) {
return c.PrepareContext(context.Background(), query)
}
func (c *SQLiteConn) PrepareContext(ctx context.Context, query string) (st driver.Stmt, err error) {
err = retryOnBusy(ctx, func() error {
st, err = c.conn.PrepareContext(ctx, query)
err = processSQLiteError(err)
return err
})
if err != nil {
return nil, err
}
return &SQLiteStmt{st.(stmt)}, nil
}
func (c *SQLiteConn) Exec(query string, args []driver.Value) (driver.Result, error) {
return c.ExecContext(context.Background(), query, toNamedValues(args))
}
func (c *SQLiteConn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (result driver.Result, err error) {
err = retryOnBusy(ctx, func() error {
result, err = c.conn.ExecContext(ctx, query, args)
err = processSQLiteError(err)
return err
})
return
}
func (c *SQLiteConn) Query(query string, args []driver.Value) (driver.Rows, error) {
return c.QueryContext(context.Background(), query, toNamedValues(args))
}
func (c *SQLiteConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (rows driver.Rows, err error) {
err = retryOnBusy(ctx, func() error {
rows, err = c.conn.QueryContext(ctx, query, args)
err = processSQLiteError(err)
return err
})
return
}
func (c *SQLiteConn) Close() error {
// see: https://www.sqlite.org/pragma.html#pragma_optimize
const onClose = "PRAGMA analysis_limit=1000; PRAGMA optimize;"
_, _ = c.conn.ExecContext(context.Background(), onClose, nil)
return c.conn.Close()
}
type SQLiteTx struct {
context.Context
driver.Tx
}
func (tx *SQLiteTx) Commit() (err error) {
err = retryOnBusy(tx.Context, func() error {
err = tx.Tx.Commit()
err = processSQLiteError(err)
return err
})
return
}
func (tx *SQLiteTx) Rollback() (err error) {
err = retryOnBusy(tx.Context, func() error {
err = tx.Tx.Rollback()
err = processSQLiteError(err)
return err
})
return
}
type SQLiteStmt struct{ stmt }
func (stmt *SQLiteStmt) Exec(args []driver.Value) (driver.Result, error) {
return stmt.ExecContext(context.Background(), toNamedValues(args))
}
func (stmt *SQLiteStmt) ExecContext(ctx context.Context, args []driver.NamedValue) (res driver.Result, err error) {
err = retryOnBusy(ctx, func() error {
res, err = stmt.stmt.ExecContext(ctx, args)
err = processSQLiteError(err)
return err
})
return
}
func (stmt *SQLiteStmt) Query(args []driver.Value) (driver.Rows, error) {
return stmt.QueryContext(context.Background(), toNamedValues(args))
}
func (stmt *SQLiteStmt) QueryContext(ctx context.Context, args []driver.NamedValue) (rows driver.Rows, err error) {
err = retryOnBusy(ctx, func() error {
rows, err = stmt.stmt.QueryContext(ctx, args)
err = processSQLiteError(err)
return err
})
return
}
type conn interface {
driver.Conn
driver.ConnPrepareContext
driver.ExecerContext
driver.QueryerContext
driver.ConnBeginTx
}
type stmt interface {
driver.Stmt
driver.StmtExecContext
driver.StmtQueryContext
}
// retryOnBusy will retry given function on returned 'errBusy'.
func retryOnBusy(ctx context.Context, fn func() error) error {
if err := fn(); err != errBusy {
return err
}
return retryOnBusySlow(ctx, fn)
}
// retryOnBusySlow is the outlined form of retryOnBusy, to allow the fast path (i.e. only
// 1 attempt) to be inlined, leaving the slow retry loop to be a separate function call.
func retryOnBusySlow(ctx context.Context, fn func() error) error {
var backoff time.Duration
for i := 0; ; i++ {
// backoff according to a multiplier of 2ms * 2^2n,
// up to a maximum possible backoff time of 5 minutes.
//
// this works out as the following:
// 4ms
// 16ms
// 64ms
// 256ms
// 1.024s
// 4.096s
// 16.384s
// 1m5.536s
// 4m22.144s
backoff = 2 * time.Millisecond * (1 << (2*i + 1))
if backoff >= 5*time.Minute {
break
}
select {
// Context cancelled.
case <-ctx.Done():
return ctx.Err()
// Backoff for some time.
case <-time.After(backoff):
}
// Perform func.
err := fn()
if err != errBusy {
// May be nil, or may be
// some other error, either
// way return here.
return err
}
}
return gtserror.Newf("%w (waited > %s)", db.ErrBusyTimeout, backoff)
}
// toNamedValues converts older driver.Value types to driver.NamedValue types.
func toNamedValues(args []driver.Value) []driver.NamedValue {
if args == nil {
return nil
}
args2 := make([]driver.NamedValue, len(args))
for i := range args {
args2[i] = driver.NamedValue{
Ordinal: i + 1,
Value: args[i],
}
}
return args2
}