package mssql import ( "context" "database/sql" "database/sql/driver" "encoding/binary" "errors" "fmt" "io" "math" "net" "reflect" "strings" "time" ) var driverInstance = &Driver{processQueryText: true} var driverInstanceNoProcess = &Driver{processQueryText: false} func init() { sql.Register("mssql", driverInstance) sql.Register("sqlserver", driverInstanceNoProcess) createDialer = func(p *connectParams) dialer { return tcpDialer{&net.Dialer{KeepAlive: p.keepAlive}} } } // Abstract the dialer for testing and for non-TCP based connections. type dialer interface { Dial(ctx context.Context, addr string) (net.Conn, error) } var createDialer func(p *connectParams) dialer type tcpDialer struct { nd *net.Dialer } func (d tcpDialer) Dial(ctx context.Context, addr string) (net.Conn, error) { return d.nd.DialContext(ctx, "tcp", addr) } type Driver struct { log optionalLogger processQueryText bool } // OpenConnector opens a new connector. Useful to dial with a context. func (d *Driver) OpenConnector(dsn string) (*Connector, error) { params, err := parseConnectParams(dsn) if err != nil { return nil, err } return &Connector{ params: params, driver: d, }, nil } func (d *Driver) Open(dsn string) (driver.Conn, error) { return d.open(context.Background(), dsn) } func SetLogger(logger Logger) { driverInstance.SetLogger(logger) driverInstanceNoProcess.SetLogger(logger) } func (d *Driver) SetLogger(logger Logger) { d.log = optionalLogger{logger} } // NewConnector creates a new connector from a DSN. // The returned connector may be used with sql.OpenDB. func NewConnector(dsn string) (*Connector, error) { params, err := parseConnectParams(dsn) if err != nil { return nil, err } c := &Connector{ params: params, driver: driverInstanceNoProcess, } return c, nil } // Connector holds the parsed DSN and is ready to make a new connection // at any time. // // In the future, settings that cannot be passed through a string DSN // may be set directly on the connector. type Connector struct { params connectParams driver *Driver // SessionInitSQL is executed after marking a given session to be reset. // When not present, the next query will still reset the session to the // database defaults. // // When present the connection will immediately mark the session to // be reset, then execute the SessionInitSQL text to setup the session // that may be different from the base database defaults. // // For Example, the application relies on the following defaults // but is not allowed to set them at the database system level. // // SET XACT_ABORT ON; // SET TEXTSIZE -1; // SET ANSI_NULLS ON; // SET LOCK_TIMEOUT 10000; // // SessionInitSQL should not attempt to manually call sp_reset_connection. // This will happen at the TDS layer. // // SessionInitSQL is optional. The session will be reset even if // SessionInitSQL is empty. SessionInitSQL string } type Conn struct { connector *Connector sess *tdsSession transactionCtx context.Context resetSession bool processQueryText bool connectionGood bool outs map[string]interface{} } func (c *Conn) checkBadConn(err error) error { // this is a hack to address Issue #275 // we set connectionGood flag to false if // error indicates that connection is not usable // but we return actual error instead of ErrBadConn // this will cause connection to stay in a pool // but next request to this connection will return ErrBadConn // it might be possible to revise this hack after // https://github.com/golang/go/issues/20807 // is implemented switch err { case nil: return nil case io.EOF: c.connectionGood = false return driver.ErrBadConn case driver.ErrBadConn: // It is an internal programming error if driver.ErrBadConn // is ever passed to this function. driver.ErrBadConn should // only ever be returned in response to a *mssql.Conn.connectionGood == false // check in the external facing API. panic("driver.ErrBadConn in checkBadConn. This should not happen.") } switch err.(type) { case net.Error: c.connectionGood = false return err case StreamError: c.connectionGood = false return err default: return err } } func (c *Conn) clearOuts() { c.outs = nil } func (c *Conn) simpleProcessResp(ctx context.Context) error { tokchan := make(chan tokenStruct, 5) go processResponse(ctx, c.sess, tokchan, c.outs) c.clearOuts() for tok := range tokchan { switch token := tok.(type) { case doneStruct: if token.isError() { return c.checkBadConn(token.getError()) } case error: return c.checkBadConn(token) } } return nil } func (c *Conn) Commit() error { if !c.connectionGood { return driver.ErrBadConn } if err := c.sendCommitRequest(); err != nil { return c.checkBadConn(err) } return c.simpleProcessResp(c.transactionCtx) } func (c *Conn) sendCommitRequest() error { headers := []headerStruct{ {hdrtype: dataStmHdrTransDescr, data: transDescrHdr{c.sess.tranid, 1}.pack()}, } reset := c.resetSession c.resetSession = false if err := sendCommitXact(c.sess.buf, headers, "", 0, 0, "", reset); err != nil { if c.sess.logFlags&logErrors != 0 { c.sess.log.Printf("Failed to send CommitXact with %v", err) } c.connectionGood = false return fmt.Errorf("Faild to send CommitXact: %v", err) } return nil } func (c *Conn) Rollback() error { if !c.connectionGood { return driver.ErrBadConn } if err := c.sendRollbackRequest(); err != nil { return c.checkBadConn(err) } return c.simpleProcessResp(c.transactionCtx) } func (c *Conn) sendRollbackRequest() error { headers := []headerStruct{ {hdrtype: dataStmHdrTransDescr, data: transDescrHdr{c.sess.tranid, 1}.pack()}, } reset := c.resetSession c.resetSession = false if err := sendRollbackXact(c.sess.buf, headers, "", 0, 0, "", reset); err != nil { if c.sess.logFlags&logErrors != 0 { c.sess.log.Printf("Failed to send RollbackXact with %v", err) } c.connectionGood = false return fmt.Errorf("Failed to send RollbackXact: %v", err) } return nil } func (c *Conn) Begin() (driver.Tx, error) { return c.begin(context.Background(), isolationUseCurrent) } func (c *Conn) begin(ctx context.Context, tdsIsolation isoLevel) (tx driver.Tx, err error) { if !c.connectionGood { return nil, driver.ErrBadConn } err = c.sendBeginRequest(ctx, tdsIsolation) if err != nil { return nil, c.checkBadConn(err) } tx, err = c.processBeginResponse(ctx) if err != nil { return nil, c.checkBadConn(err) } return } func (c *Conn) sendBeginRequest(ctx context.Context, tdsIsolation isoLevel) error { c.transactionCtx = ctx headers := []headerStruct{ {hdrtype: dataStmHdrTransDescr, data: transDescrHdr{0, 1}.pack()}, } reset := c.resetSession c.resetSession = false if err := sendBeginXact(c.sess.buf, headers, tdsIsolation, "", reset); err != nil { if c.sess.logFlags&logErrors != 0 { c.sess.log.Printf("Failed to send BeginXact with %v", err) } c.connectionGood = false return fmt.Errorf("Failed to send BeginXact: %v", err) } return nil } func (c *Conn) processBeginResponse(ctx context.Context) (driver.Tx, error) { if err := c.simpleProcessResp(ctx); err != nil { return nil, err } // successful BEGINXACT request will return sess.tranid // for started transaction return c, nil } func (d *Driver) open(ctx context.Context, dsn string) (*Conn, error) { params, err := parseConnectParams(dsn) if err != nil { return nil, err } return d.connect(ctx, params) } // connect to the server, using the provided context for dialing only. func (d *Driver) connect(ctx context.Context, params connectParams) (*Conn, error) { sess, err := connect(ctx, d.log, params) if err != nil { // main server failed, try fail-over partner if params.failOverPartner == "" { return nil, err } params.host = params.failOverPartner if params.failOverPort != 0 { params.port = params.failOverPort } sess, err = connect(ctx, d.log, params) if err != nil { // fail-over partner also failed, now fail return nil, err } } conn := &Conn{ sess: sess, transactionCtx: context.Background(), processQueryText: d.processQueryText, connectionGood: true, } conn.sess.log = d.log return conn, nil } func (c *Conn) Close() error { return c.sess.buf.transport.Close() } type Stmt struct { c *Conn query string paramCount int notifSub *queryNotifSub } type queryNotifSub struct { msgText string options string timeout uint32 } func (c *Conn) Prepare(query string) (driver.Stmt, error) { if !c.connectionGood { return nil, driver.ErrBadConn } if len(query) > 10 && strings.EqualFold(query[:10], "INSERTBULK") { return c.prepareCopyIn(context.Background(), query) } return c.prepareContext(context.Background(), query) } func (c *Conn) prepareContext(ctx context.Context, query string) (*Stmt, error) { paramCount := -1 if c.processQueryText { query, paramCount = parseParams(query) } return &Stmt{c, query, paramCount, nil}, nil } func (s *Stmt) Close() error { return nil } func (s *Stmt) SetQueryNotification(id, options string, timeout time.Duration) { to := uint32(timeout / time.Second) if to < 1 { to = 1 } s.notifSub = &queryNotifSub{id, options, to} } func (s *Stmt) NumInput() int { return s.paramCount } func (s *Stmt) sendQuery(args []namedValue) (err error) { headers := []headerStruct{ {hdrtype: dataStmHdrTransDescr, data: transDescrHdr{s.c.sess.tranid, 1}.pack()}, } if s.notifSub != nil { headers = append(headers, headerStruct{ hdrtype: dataStmHdrQueryNotif, data: queryNotifHdr{ s.notifSub.msgText, s.notifSub.options, s.notifSub.timeout, }.pack(), }) } conn := s.c // no need to check number of parameters here, it is checked by database/sql if conn.sess.logFlags&logSQL != 0 { conn.sess.log.Println(s.query) } if conn.sess.logFlags&logParams != 0 && len(args) > 0 { for i := 0; i < len(args); i++ { if len(args[i].Name) > 0 { s.c.sess.log.Printf("\t@%s\t%v\n", args[i].Name, args[i].Value) } else { s.c.sess.log.Printf("\t@p%d\t%v\n", i+1, args[i].Value) } } } reset := conn.resetSession conn.resetSession = false if len(args) == 0 { if err = sendSqlBatch72(conn.sess.buf, s.query, headers, reset); err != nil { if conn.sess.logFlags&logErrors != 0 { conn.sess.log.Printf("Failed to send SqlBatch with %v", err) } conn.connectionGood = false return fmt.Errorf("failed to send SQL Batch: %v", err) } } else { proc := sp_ExecuteSql var params []param if isProc(s.query) { proc.name = s.query params, _, err = s.makeRPCParams(args, 0) if err != nil { return } } else { var decls []string params, decls, err = s.makeRPCParams(args, 2) if err != nil { return } params[0] = makeStrParam(s.query) params[1] = makeStrParam(strings.Join(decls, ",")) } if err = sendRpc(conn.sess.buf, headers, proc, 0, params, reset); err != nil { if conn.sess.logFlags&logErrors != 0 { conn.sess.log.Printf("Failed to send Rpc with %v", err) } conn.connectionGood = false return fmt.Errorf("Failed to send RPC: %v", err) } } return } // isProc takes the query text in s and determines if it is a stored proc name // or SQL text. func isProc(s string) bool { if len(s) == 0 { return false } if s[0] == '[' && s[len(s)-1] == ']' && strings.ContainsAny(s, "\n\r") == false { return true } return !strings.ContainsAny(s, " \t\n\r;") } func (s *Stmt) makeRPCParams(args []namedValue, offset int) ([]param, []string, error) { var err error params := make([]param, len(args)+offset) decls := make([]string, len(args)) for i, val := range args { params[i+offset], err = s.makeParam(val.Value) if err != nil { return nil, nil, err } var name string if len(val.Name) > 0 { name = "@" + val.Name } else { name = fmt.Sprintf("@p%d", val.Ordinal) } params[i+offset].Name = name decls[i] = fmt.Sprintf("%s %s", name, makeDecl(params[i+offset].ti)) } return params, decls, nil } type namedValue struct { Name string Ordinal int Value driver.Value } func convertOldArgs(args []driver.Value) []namedValue { list := make([]namedValue, len(args)) for i, v := range args { list[i] = namedValue{ Ordinal: i + 1, Value: v, } } return list } func (s *Stmt) Query(args []driver.Value) (driver.Rows, error) { return s.queryContext(context.Background(), convertOldArgs(args)) } func (s *Stmt) queryContext(ctx context.Context, args []namedValue) (rows driver.Rows, err error) { if !s.c.connectionGood { return nil, driver.ErrBadConn } if err = s.sendQuery(args); err != nil { return nil, s.c.checkBadConn(err) } return s.processQueryResponse(ctx) } func (s *Stmt) processQueryResponse(ctx context.Context) (res driver.Rows, err error) { tokchan := make(chan tokenStruct, 5) ctx, cancel := context.WithCancel(ctx) go processResponse(ctx, s.c.sess, tokchan, s.c.outs) s.c.clearOuts() // process metadata var cols []columnStruct loop: for tok := range tokchan { switch token := tok.(type) { // By ignoring DONE token we effectively // skip empty result-sets. // This improves results in queries like that: // set nocount on; select 1 // see TestIgnoreEmptyResults test //case doneStruct: //break loop case []columnStruct: cols = token break loop case doneStruct: if token.isError() { return nil, s.c.checkBadConn(token.getError()) } case error: return nil, s.c.checkBadConn(token) } } res = &Rows{stmt: s, tokchan: tokchan, cols: cols, cancel: cancel} return } func (s *Stmt) Exec(args []driver.Value) (driver.Result, error) { return s.exec(context.Background(), convertOldArgs(args)) } func (s *Stmt) exec(ctx context.Context, args []namedValue) (res driver.Result, err error) { if !s.c.connectionGood { return nil, driver.ErrBadConn } if err = s.sendQuery(args); err != nil { return nil, s.c.checkBadConn(err) } if res, err = s.processExec(ctx); err != nil { return nil, s.c.checkBadConn(err) } return } func (s *Stmt) processExec(ctx context.Context) (res driver.Result, err error) { tokchan := make(chan tokenStruct, 5) go processResponse(ctx, s.c.sess, tokchan, s.c.outs) s.c.clearOuts() var rowCount int64 for token := range tokchan { switch token := token.(type) { case doneInProcStruct: if token.Status&doneCount != 0 { rowCount += int64(token.RowCount) } case doneStruct: if token.Status&doneCount != 0 { rowCount += int64(token.RowCount) } if token.isError() { return nil, token.getError() } case error: return nil, token } } return &Result{s.c, rowCount}, nil } type Rows struct { stmt *Stmt cols []columnStruct tokchan chan tokenStruct nextCols []columnStruct cancel func() } func (rc *Rows) Close() error { rc.cancel() for _ = range rc.tokchan { } rc.tokchan = nil return nil } func (rc *Rows) Columns() (res []string) { res = make([]string, len(rc.cols)) for i, col := range rc.cols { res[i] = col.ColName } return } func (rc *Rows) Next(dest []driver.Value) error { if !rc.stmt.c.connectionGood { return driver.ErrBadConn } if rc.nextCols != nil { return io.EOF } for tok := range rc.tokchan { switch tokdata := tok.(type) { case []columnStruct: rc.nextCols = tokdata return io.EOF case []interface{}: for i := range dest { dest[i] = tokdata[i] } return nil case doneStruct: if tokdata.isError() { return rc.stmt.c.checkBadConn(tokdata.getError()) } case error: return rc.stmt.c.checkBadConn(tokdata) } } return io.EOF } func (rc *Rows) HasNextResultSet() bool { return rc.nextCols != nil } func (rc *Rows) NextResultSet() error { rc.cols = rc.nextCols rc.nextCols = nil if rc.cols == nil { return io.EOF } return nil } // It should return // the value type that can be used to scan types into. For example, the database // column type "bigint" this should return "reflect.TypeOf(int64(0))". func (r *Rows) ColumnTypeScanType(index int) reflect.Type { return makeGoLangScanType(r.cols[index].ti) } // RowsColumnTypeDatabaseTypeName may be implemented by Rows. It should return the // database system type name without the length. Type names should be uppercase. // Examples of returned types: "VARCHAR", "NVARCHAR", "VARCHAR2", "CHAR", "TEXT", // "DECIMAL", "SMALLINT", "INT", "BIGINT", "BOOL", "[]BIGINT", "JSONB", "XML", // "TIMESTAMP". func (r *Rows) ColumnTypeDatabaseTypeName(index int) string { return makeGoLangTypeName(r.cols[index].ti) } // RowsColumnTypeLength may be implemented by Rows. It should return the length // of the column type if the column is a variable length type. If the column is // not a variable length type ok should return false. // If length is not limited other than system limits, it should return math.MaxInt64. // The following are examples of returned values for various types: // TEXT (math.MaxInt64, true) // varchar(10) (10, true) // nvarchar(10) (10, true) // decimal (0, false) // int (0, false) // bytea(30) (30, true) func (r *Rows) ColumnTypeLength(index int) (int64, bool) { return makeGoLangTypeLength(r.cols[index].ti) } // It should return // the precision and scale for decimal types. If not applicable, ok should be false. // The following are examples of returned values for various types: // decimal(38, 4) (38, 4, true) // int (0, 0, false) // decimal (math.MaxInt64, math.MaxInt64, true) func (r *Rows) ColumnTypePrecisionScale(index int) (int64, int64, bool) { return makeGoLangTypePrecisionScale(r.cols[index].ti) } // The nullable value should // be true if it is known the column may be null, or false if the column is known // to be not nullable. // If the column nullability is unknown, ok should be false. func (r *Rows) ColumnTypeNullable(index int) (nullable, ok bool) { nullable = r.cols[index].Flags&colFlagNullable != 0 ok = true return } func makeStrParam(val string) (res param) { res.ti.TypeId = typeNVarChar res.buffer = str2ucs2(val) res.ti.Size = len(res.buffer) return } func (s *Stmt) makeParam(val driver.Value) (res param, err error) { if val == nil { res.ti.TypeId = typeNull res.buffer = nil res.ti.Size = 0 return } switch val := val.(type) { case int64: res.ti.TypeId = typeIntN res.buffer = make([]byte, 8) res.ti.Size = 8 binary.LittleEndian.PutUint64(res.buffer, uint64(val)) case float64: res.ti.TypeId = typeFltN res.ti.Size = 8 res.buffer = make([]byte, 8) binary.LittleEndian.PutUint64(res.buffer, math.Float64bits(val)) case []byte: res.ti.TypeId = typeBigVarBin res.ti.Size = len(val) res.buffer = val case string: res = makeStrParam(val) case bool: res.ti.TypeId = typeBitN res.ti.Size = 1 res.buffer = make([]byte, 1) if val { res.buffer[0] = 1 } case time.Time: if s.c.sess.loginAck.TDSVersion >= verTDS73 { res.ti.TypeId = typeDateTimeOffsetN res.ti.Scale = 7 res.buffer = encodeDateTimeOffset(val, int(res.ti.Scale)) res.ti.Size = len(res.buffer) } else { res.ti.TypeId = typeDateTimeN res.buffer = encodeDateTime(val) res.ti.Size = len(res.buffer) } default: return s.makeParamExtra(val) } return } type Result struct { c *Conn rowsAffected int64 } func (r *Result) RowsAffected() (int64, error) { return r.rowsAffected, nil } func (r *Result) LastInsertId() (int64, error) { s, err := r.c.Prepare("select cast(@@identity as bigint)") if err != nil { return 0, err } defer s.Close() rows, err := s.Query(nil) if err != nil { return 0, err } defer rows.Close() dest := make([]driver.Value, 1) err = rows.Next(dest) if err != nil { return 0, err } if dest[0] == nil { return -1, errors.New("There is no generated identity value") } lastInsertId := dest[0].(int64) return lastInsertId, nil } var _ driver.Pinger = &Conn{} // Ping is used to check if the remote server is available and satisfies the Pinger interface. func (c *Conn) Ping(ctx context.Context) error { if !c.connectionGood { return driver.ErrBadConn } stmt := &Stmt{c, `select 1;`, 0, nil} _, err := stmt.ExecContext(ctx, nil) return err } var _ driver.ConnBeginTx = &Conn{} // BeginTx satisfies ConnBeginTx. func (c *Conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) { if !c.connectionGood { return nil, driver.ErrBadConn } if opts.ReadOnly { return nil, errors.New("Read-only transactions are not supported") } var tdsIsolation isoLevel switch sql.IsolationLevel(opts.Isolation) { case sql.LevelDefault: tdsIsolation = isolationUseCurrent case sql.LevelReadUncommitted: tdsIsolation = isolationReadUncommited case sql.LevelReadCommitted: tdsIsolation = isolationReadCommited case sql.LevelWriteCommitted: return nil, errors.New("LevelWriteCommitted isolation level is not supported") case sql.LevelRepeatableRead: tdsIsolation = isolationRepeatableRead case sql.LevelSnapshot: tdsIsolation = isolationSnapshot case sql.LevelSerializable: tdsIsolation = isolationSerializable case sql.LevelLinearizable: return nil, errors.New("LevelLinearizable isolation level is not supported") default: return nil, errors.New("Isolation level is not supported or unknown") } return c.begin(ctx, tdsIsolation) } func (c *Conn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) { if !c.connectionGood { return nil, driver.ErrBadConn } if len(query) > 10 && strings.EqualFold(query[:10], "INSERTBULK") { return c.prepareCopyIn(ctx, query) } return c.prepareContext(ctx, query) } func (s *Stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) { if !s.c.connectionGood { return nil, driver.ErrBadConn } list := make([]namedValue, len(args)) for i, nv := range args { list[i] = namedValue(nv) } return s.queryContext(ctx, list) } func (s *Stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) { if !s.c.connectionGood { return nil, driver.ErrBadConn } list := make([]namedValue, len(args)) for i, nv := range args { list[i] = namedValue(nv) } return s.exec(ctx, list) }