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Copy pathsql.go
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429 lines (363 loc) · 10.2 KB
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// Package stdlib is the compatibility layer from pgx to database/sql.
//
// A database/sql connection can be established through sql.Open.
//
// db, err := sql.Open("pgx", "postgres://pgx_md5:secret@localhost:5432/pgx_test?sslmode=disable")
// if err != nil {
// return err
// }
//
// Or from a DSN string.
//
// db, err := sql.Open("pgx", "user=postgres password=secret host=localhost port=5432 database=pgx_test sslmode=disable")
// if err != nil {
// return err
// }
//
// Or a normal pgx connection pool can be established and the database/sql
// connection can be created through stdlib.OpenFromConnPool(). This allows
// more control over the connection process (such as TLS), more control
// over the connection pool, setting an AfterConnect hook, and using both
// database/sql and pgx interfaces as needed.
//
// connConfig := pgx.ConnConfig{
// Host: "localhost",
// User: "pgx_md5",
// Password: "secret",
// Database: "pgx_test",
// }
//
// config := pgx.ConnPoolConfig{ConnConfig: connConfig}
// pool, err := pgx.NewConnPool(config)
// if err != nil {
// return err
// }
//
// db, err := stdlib.OpenFromConnPool(pool)
// if err != nil {
// t.Fatalf("Unable to create connection pool: %v", err)
// }
//
// If the database/sql connection is established through
// stdlib.OpenFromConnPool then access to a pgx *ConnPool can be regained
// through db.Driver(). This allows writing a fast path for pgx while
// preserving compatibility with other drivers and database
//
// if driver, ok := db.Driver().(*stdlib.Driver); ok && driver.Pool != nil {
// // fast path with pgx
// } else {
// // normal path for other drivers and databases
// }
package stdlib
import (
"context"
"database/sql"
"database/sql/driver"
"errors"
"fmt"
"io"
"sync"
"github.com/jackc/pgx"
"github.com/jackc/pgx/pgtype"
)
var (
openFromConnPoolCountMu sync.Mutex
openFromConnPoolCount int
)
// oids that map to intrinsic database/sql types. These will be allowed to be
// binary, anything else will be forced to text format
var databaseSqlOids map[pgtype.Oid]bool
func init() {
d := &Driver{}
sql.Register("pgx", d)
databaseSqlOids = make(map[pgtype.Oid]bool)
databaseSqlOids[pgtype.BoolOid] = true
databaseSqlOids[pgtype.ByteaOid] = true
databaseSqlOids[pgtype.CidOid] = true
databaseSqlOids[pgtype.DateOid] = true
databaseSqlOids[pgtype.Float4Oid] = true
databaseSqlOids[pgtype.Float8Oid] = true
databaseSqlOids[pgtype.Int2Oid] = true
databaseSqlOids[pgtype.Int4Oid] = true
databaseSqlOids[pgtype.Int8Oid] = true
databaseSqlOids[pgtype.OidOid] = true
databaseSqlOids[pgtype.TimestampOid] = true
databaseSqlOids[pgtype.TimestamptzOid] = true
databaseSqlOids[pgtype.XidOid] = true
}
type Driver struct {
Pool *pgx.ConnPool
}
func (d *Driver) Open(name string) (driver.Conn, error) {
if d.Pool != nil {
conn, err := d.Pool.Acquire()
if err != nil {
return nil, err
}
return &Conn{conn: conn, pool: d.Pool}, nil
}
connConfig, err := pgx.ParseConnectionString(name)
if err != nil {
return nil, err
}
conn, err := pgx.Connect(connConfig)
if err != nil {
return nil, err
}
c := &Conn{conn: conn}
return c, nil
}
// OpenFromConnPool takes the existing *pgx.ConnPool pool and returns a *sql.DB
// with pool as the backend. This enables full control over the connection
// process and configuration while maintaining compatibility with the
// database/sql interface. In addition, by calling Driver() on the returned
// *sql.DB and typecasting to *stdlib.Driver a reference to the pgx.ConnPool can
// be reaquired later. This allows fast paths targeting pgx to be used while
// still maintaining compatibility with other databases and drivers.
//
// pool connection size must be at least 2.
func OpenFromConnPool(pool *pgx.ConnPool) (*sql.DB, error) {
d := &Driver{Pool: pool}
openFromConnPoolCountMu.Lock()
name := fmt.Sprintf("pgx-%d", openFromConnPoolCount)
openFromConnPoolCount++
openFromConnPoolCountMu.Unlock()
sql.Register(name, d)
db, err := sql.Open(name, "")
if err != nil {
return nil, err
}
// Presumably OpenFromConnPool is being used because the user wants to use
// database/sql most of the time, but fast path with pgx some of the time.
// Allow database/sql to use all the connections, but release 2 idle ones.
// Don't have database/sql immediately release all idle connections because
// that would mean that prepared statements would be lost (which kills
// performance if the prepared statements constantly have to be reprepared)
stat := pool.Stat()
if stat.MaxConnections <= 2 {
return nil, errors.New("pool connection size must be at least 3")
}
db.SetMaxIdleConns(stat.MaxConnections - 2)
db.SetMaxOpenConns(stat.MaxConnections)
return db, nil
}
type Conn struct {
conn *pgx.Conn
pool *pgx.ConnPool
psCount int64 // Counter used for creating unique prepared statement names
}
func (c *Conn) Prepare(query string) (driver.Stmt, error) {
if !c.conn.IsAlive() {
return nil, driver.ErrBadConn
}
name := fmt.Sprintf("pgx_%d", c.psCount)
c.psCount++
ps, err := c.conn.Prepare(name, query)
if err != nil {
return nil, err
}
restrictBinaryToDatabaseSqlTypes(ps)
return &Stmt{ps: ps, conn: c}, nil
}
func (c *Conn) Close() error {
if c.pool != nil {
c.pool.Release(c.conn)
return nil
}
return c.conn.Close()
}
func (c *Conn) Begin() (driver.Tx, error) {
if !c.conn.IsAlive() {
return nil, driver.ErrBadConn
}
_, err := c.conn.Exec("begin")
if err != nil {
return nil, err
}
return &Tx{conn: c.conn}, nil
}
func (c *Conn) Exec(query string, argsV []driver.Value) (driver.Result, error) {
if !c.conn.IsAlive() {
return nil, driver.ErrBadConn
}
args := valueToInterface(argsV)
commandTag, err := c.conn.Exec(query, args...)
return driver.RowsAffected(commandTag.RowsAffected()), err
}
func (c *Conn) Query(query string, argsV []driver.Value) (driver.Rows, error) {
if !c.conn.IsAlive() {
return nil, driver.ErrBadConn
}
ps, err := c.conn.Prepare("", query)
if err != nil {
return nil, err
}
restrictBinaryToDatabaseSqlTypes(ps)
return c.queryPrepared("", argsV)
}
func (c *Conn) QueryContext(ctx context.Context, query string, argsV []driver.NamedValue) (driver.Rows, error) {
if !c.conn.IsAlive() {
return nil, driver.ErrBadConn
}
ps, err := c.conn.PrepareExContext(ctx, "", query, nil)
if err != nil {
return nil, err
}
restrictBinaryToDatabaseSqlTypes(ps)
return c.queryPreparedContext(ctx, "", argsV)
}
func (c *Conn) queryPrepared(name string, argsV []driver.Value) (driver.Rows, error) {
if !c.conn.IsAlive() {
return nil, driver.ErrBadConn
}
args := valueToInterface(argsV)
rows, err := c.conn.Query(name, args...)
if err != nil {
return nil, err
}
return &Rows{rows: rows}, nil
}
func (c *Conn) queryPreparedContext(ctx context.Context, name string, argsV []driver.NamedValue) (driver.Rows, error) {
if !c.conn.IsAlive() {
return nil, driver.ErrBadConn
}
args := namedValueToInterface(argsV)
rows, err := c.conn.QueryContext(ctx, name, args...)
if err != nil {
fmt.Println(err)
return nil, err
}
return &Rows{rows: rows}, nil
}
// Anything that isn't a database/sql compatible type needs to be forced to
// text format so that pgx.Rows.Values doesn't decode it into a native type
// (e.g. []int32)
func restrictBinaryToDatabaseSqlTypes(ps *pgx.PreparedStatement) {
for i, _ := range ps.FieldDescriptions {
intrinsic, _ := databaseSqlOids[ps.FieldDescriptions[i].DataType]
if !intrinsic {
ps.FieldDescriptions[i].FormatCode = pgx.TextFormatCode
}
}
}
type Stmt struct {
ps *pgx.PreparedStatement
conn *Conn
}
func (s *Stmt) Close() error {
return s.conn.conn.Deallocate(s.ps.Name)
}
func (s *Stmt) NumInput() int {
return len(s.ps.ParameterOids)
}
func (s *Stmt) Exec(argsV []driver.Value) (driver.Result, error) {
return s.conn.Exec(s.ps.Name, argsV)
}
func (s *Stmt) Query(argsV []driver.Value) (driver.Rows, error) {
return s.conn.queryPrepared(s.ps.Name, argsV)
}
type Rows struct {
rows *pgx.Rows
values []interface{}
}
func (r *Rows) Columns() []string {
fieldDescriptions := r.rows.FieldDescriptions()
names := make([]string, 0, len(fieldDescriptions))
for _, fd := range fieldDescriptions {
names = append(names, fd.Name)
}
return names
}
func (r *Rows) Close() error {
r.rows.Close()
return nil
}
func (r *Rows) Next(dest []driver.Value) error {
if r.values == nil {
r.values = make([]interface{}, len(r.rows.FieldDescriptions()))
for i, fd := range r.rows.FieldDescriptions() {
switch fd.DataType {
case pgtype.BoolOid:
r.values[i] = &pgtype.Bool{}
case pgtype.ByteaOid:
r.values[i] = &pgtype.Bytea{}
case pgtype.CidOid:
r.values[i] = &pgtype.Cid{}
case pgtype.DateOid:
r.values[i] = &pgtype.Date{}
case pgtype.Float4Oid:
r.values[i] = &pgtype.Float4{}
case pgtype.Float8Oid:
r.values[i] = &pgtype.Float8{}
case pgtype.Int2Oid:
r.values[i] = &pgtype.Int2{}
case pgtype.Int4Oid:
r.values[i] = &pgtype.Int4{}
case pgtype.Int8Oid:
r.values[i] = &pgtype.Int8{}
case pgtype.OidOid:
r.values[i] = &pgtype.OidValue{}
case pgtype.TimestampOid:
r.values[i] = &pgtype.Timestamp{}
case pgtype.TimestamptzOid:
r.values[i] = &pgtype.Timestamptz{}
case pgtype.XidOid:
r.values[i] = &pgtype.Xid{}
default:
r.values[i] = &pgtype.GenericText{}
}
}
}
more := r.rows.Next()
if !more {
if r.rows.Err() == nil {
return io.EOF
} else {
return r.rows.Err()
}
}
err := r.rows.Scan(r.values...)
if err != nil {
return err
}
for i, v := range r.values {
dest[i], err = v.(driver.Valuer).Value()
if err != nil {
return err
}
}
return nil
}
func valueToInterface(argsV []driver.Value) []interface{} {
args := make([]interface{}, 0, len(argsV))
for _, v := range argsV {
if v != nil {
args = append(args, v.(interface{}))
} else {
args = append(args, nil)
}
}
return args
}
func namedValueToInterface(argsV []driver.NamedValue) []interface{} {
args := make([]interface{}, 0, len(argsV))
for _, v := range argsV {
if v.Value != nil {
args = append(args, v.Value.(interface{}))
} else {
args = append(args, nil)
}
}
return args
}
type Tx struct {
conn *pgx.Conn
}
func (t *Tx) Commit() error {
_, err := t.conn.Exec("commit")
return err
}
func (t *Tx) Rollback() error {
_, err := t.conn.Exec("rollback")
return err
}