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package pg
import (
"context"
"errors"
"io"
"sync"
"time"
"github.com/go-pg/pg/internal"
"github.com/go-pg/pg/internal/pool"
"github.com/go-pg/pg/orm"
)
var errTxDone = errors.New("pg: transaction has already been committed or rolled back")
// Tx is an in-progress database transaction. It is safe for concurrent use
// by multiple goroutines.
//
// A transaction must end with a call to Commit or Rollback.
//
// After a call to Commit or Rollback, all operations on the transaction fail
// with ErrTxDone.
//
// The statements prepared for a transaction by calling the transaction's
// Prepare or Stmt methods are closed by the call to Commit or Rollback.
type Tx struct {
db *baseDB
ctx context.Context
stmtsMu sync.Mutex
stmts []*Stmt
}
var _ orm.DB = (*Tx)(nil)
// Begin starts a transaction. Most callers should use RunInTransaction instead.
func (db *baseDB) Begin() (*Tx, error) {
tx := &Tx{
db: db.withPool(pool.NewSingleConnPool(db.pool)),
ctx: db.db.Context(),
}
err := tx.begin()
if err != nil {
tx.close()
return nil, err
}
return tx, nil
}
// RunInTransaction runs a function in a transaction. If function
// returns an error transaction is rollbacked, otherwise transaction
// is committed.
func (db *baseDB) RunInTransaction(fn func(*Tx) error) error {
tx, err := db.Begin()
if err != nil {
return err
}
return tx.RunInTransaction(fn)
}
// Begin returns current transaction. It does not start new transaction.
func (tx *Tx) Begin() (*Tx, error) {
return tx, nil
}
// RunInTransaction runs a function in the transaction. If function
// returns an error transaction is rollbacked, otherwise transaction
// is committed.
func (tx *Tx) RunInTransaction(fn func(*Tx) error) error {
defer func() {
if err := recover(); err != nil {
_ = tx.Rollback()
panic(err)
}
}()
if err := fn(tx); err != nil {
_ = tx.Rollback()
return err
}
return tx.Commit()
}
func (tx *Tx) withConn(c context.Context, fn func(cn *pool.Conn) error) error {
err := tx.db.withConn(c, fn)
if err == pool.ErrClosed {
return errTxDone
}
return err
}
// Stmt returns a transaction-specific prepared statement
// from an existing statement.
func (tx *Tx) Stmt(stmt *Stmt) *Stmt {
stmt, err := tx.Prepare(stmt.q)
if err != nil {
return &Stmt{stickyErr: err}
}
return stmt
}
// Prepare creates a prepared statement for use within a transaction.
//
// The returned statement operates within the transaction and can no longer
// be used once the transaction has been committed or rolled back.
//
// To use an existing prepared statement on this transaction, see Tx.Stmt.
func (tx *Tx) Prepare(q string) (*Stmt, error) {
tx.stmtsMu.Lock()
defer tx.stmtsMu.Unlock()
stmt, err := prepareStmt(tx.db, q)
if err != nil {
return nil, err
}
tx.stmts = append(tx.stmts, stmt)
return stmt, nil
}
// Exec is an alias for DB.Exec.
func (tx *Tx) Exec(query interface{}, params ...interface{}) (Result, error) {
return tx.exec(context.TODO(), query, params...)
}
// ExecContext acts like Exec but additionally receives a context
func (tx *Tx) ExecContext(c context.Context, query interface{}, params ...interface{}) (Result, error) {
return tx.exec(c, query, params...)
}
func (tx *Tx) exec(c context.Context, query interface{}, params ...interface{}) (res Result, err error) {
err = tx.withConn(c, func(cn *pool.Conn) error {
event := tx.db.queryStarted(c, tx, query, params, 0)
res, err = tx.db.simpleQuery(cn, query, params...)
tx.db.queryProcessed(res, err, event)
return err
})
return res, err
}
// ExecOne is an alias for DB.ExecOne.
func (tx *Tx) ExecOne(query interface{}, params ...interface{}) (Result, error) {
return tx.execOne(context.TODO(), query, params...)
}
// ExecOneContext acts like ExecOne but additionally receives a context
func (tx *Tx) ExecOneContext(c context.Context, query interface{}, params ...interface{}) (Result, error) {
return tx.execOne(c, query, params...)
}
func (tx *Tx) execOne(c context.Context, query interface{}, params ...interface{}) (Result, error) {
res, err := tx.ExecContext(c, query, params...)
if err != nil {
return nil, err
}
if err := internal.AssertOneRow(res.RowsAffected()); err != nil {
return nil, err
}
return res, nil
}
// Query is an alias for DB.Query.
func (tx *Tx) Query(model interface{}, query interface{}, params ...interface{}) (Result, error) {
return tx.query(context.TODO(), model, query, params...)
}
// QueryContext acts like Query but additionally receives a context
func (tx *Tx) QueryContext(
c context.Context,
model interface{},
query interface{},
params ...interface{},
) (Result, error) {
return tx.query(c, model, query, params...)
}
func (tx *Tx) query(
c context.Context,
model interface{},
query interface{},
params ...interface{},
) (res Result, err error) {
err = tx.withConn(c, func(cn *pool.Conn) error {
event := tx.db.queryStarted(c, tx, query, params, 0)
res, err = tx.db.simpleQueryData(cn, model, query, params...)
tx.db.queryProcessed(res, err, event)
return err
})
if err != nil {
return nil, err
}
if mod := res.Model(); mod != nil && res.RowsReturned() > 0 {
if err = mod.AfterQuery(c, tx); err != nil {
return res, err
}
}
return res, err
}
// QueryOne is an alias for DB.QueryOne.
func (tx *Tx) QueryOne(model interface{}, query interface{}, params ...interface{}) (Result, error) {
return tx.queryOne(context.TODO(), model, query, params...)
}
// QueryOneContext acts like QueryOne but additionally receives a context
func (tx *Tx) QueryOneContext(
c context.Context,
model interface{},
query interface{},
params ...interface{},
) (Result, error) {
return tx.queryOne(c, model, query, params...)
}
func (tx *Tx) queryOne(
c context.Context,
model interface{},
query interface{},
params ...interface{},
) (Result, error) {
mod, err := orm.NewModel(model)
if err != nil {
return nil, err
}
res, err := tx.QueryContext(c, mod, query, params...)
if err != nil {
return nil, err
}
if err := internal.AssertOneRow(res.RowsAffected()); err != nil {
return nil, err
}
return res, nil
}
// Model is an alias for DB.Model.
func (tx *Tx) Model(model ...interface{}) *orm.Query {
return orm.NewQuery(tx, model...)
}
// ModelContext acts like Model but additionally receives a context
func (tx *Tx) ModelContext(c context.Context, model ...interface{}) *orm.Query {
return orm.NewQueryContext(c, tx, model...)
}
// Select is an alias for DB.Select.
func (tx *Tx) Select(model interface{}) error {
return orm.Select(tx, model)
}
// Insert is an alias for DB.Insert.
func (tx *Tx) Insert(model ...interface{}) error {
return orm.Insert(tx, model...)
}
// Update is an alias for DB.Update.
func (tx *Tx) Update(model interface{}) error {
return orm.Update(tx, model)
}
// Delete is an alias for DB.Delete.
func (tx *Tx) Delete(model interface{}) error {
return orm.Delete(tx, model)
}
// ForceDelete forces the deletion of the model with deleted_at column.
func (tx *Tx) ForceDelete(model interface{}) error {
return orm.ForceDelete(tx, model)
}
// CreateTable is an alias for DB.CreateTable.
func (tx *Tx) CreateTable(model interface{}, opt *orm.CreateTableOptions) error {
return orm.CreateTable(tx, model, opt)
}
// DropTable is an alias for DB.DropTable.
func (tx *Tx) DropTable(model interface{}, opt *orm.DropTableOptions) error {
return orm.DropTable(tx, model, opt)
}
// CopyFrom is an alias for DB.CopyFrom.
func (tx *Tx) CopyFrom(r io.Reader, query interface{}, params ...interface{}) (res Result, err error) {
err = tx.withConn(context.TODO(), func(cn *pool.Conn) error {
res, err = tx.db.copyFrom(cn, r, query, params...)
return err
})
return res, err
}
// CopyTo is an alias for DB.CopyTo.
func (tx *Tx) CopyTo(w io.Writer, query interface{}, params ...interface{}) (res Result, err error) {
err = tx.withConn(context.TODO(), func(cn *pool.Conn) error {
res, err = tx.db.copyTo(cn, w, query, params...)
return err
})
return res, err
}
// FormatQuery is an alias for DB.FormatQuery
func (tx *Tx) FormatQuery(dst []byte, query string, params ...interface{}) []byte {
return tx.db.FormatQuery(dst, query, params...)
}
func (tx *Tx) begin() error {
var lastErr error
for attempt := 0; attempt <= tx.db.opt.MaxRetries; attempt++ {
if attempt > 0 {
time.Sleep(tx.db.retryBackoff(attempt - 1))
err := tx.db.pool.(*pool.SingleConnPool).Reset()
if err != nil {
internal.Logf(err.Error())
continue
}
}
_, lastErr = tx.Exec("BEGIN")
if !tx.db.shouldRetry(lastErr) {
break
}
}
return lastErr
}
// Commit commits the transaction.
func (tx *Tx) Commit() error {
_, err := tx.Exec("COMMIT")
tx.close()
return err
}
// Rollback aborts the transaction.
func (tx *Tx) Rollback() error {
_, err := tx.Exec("ROLLBACK")
tx.close()
return err
}
func (tx *Tx) close() {
tx.stmtsMu.Lock()
defer tx.stmtsMu.Unlock()
for _, stmt := range tx.stmts {
_ = stmt.Close()
}
tx.stmts = nil
_ = tx.db.Close()
}
// Context returns the context.Context of the transaction
func (tx *Tx) Context() context.Context {
return tx.ctx
}
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