From 94e3ba7cf5ca87fd7df73bdf9f9cec809ea80d4d Mon Sep 17 00:00:00 2001
From: oscarzhao <oscarzhaosl@gmail.com>
Date: Thu, 16 Mar 2017 02:09:50 +0800
Subject: [PATCH 1/6] Add context support

For backward compatibility with Go versions < 1.8, the file ctx_backport.go
contains a redefinition of context.Context as well as a few other things.
The result is that the vast majority of the code can be shared between Go
versions.
---
 README.md         |  5 ++++
 connection.go     | 38 ++++++++++++++++++++--------
 connection_ctx.go | 48 +++++++++++++++++++++++++++++++++++
 ctx_backport.go   | 61 ++++++++++++++++++++++++++++++++++++++++++++
 ctx_go18.go       | 27 ++++++++++++++++++++
 driver.go         |  9 ++++---
 driver_test.go    |  8 ++++++
 infile.go         |  6 ++---
 packets.go        | 64 +++++++++++++++++++++++++++++------------------
 statement.go      | 18 ++++++++++---
 statement_ctx.go  | 26 +++++++++++++++++++
 transaction.go    |  6 +++--
 12 files changed, 270 insertions(+), 46 deletions(-)
 create mode 100644 connection_ctx.go
 create mode 100644 ctx_backport.go
 create mode 100644 ctx_go18.go
 create mode 100644 statement_ctx.go

diff --git a/README.md b/README.md
index a060e3cfd..ea08db9c4 100644
--- a/README.md
+++ b/README.md
@@ -418,6 +418,11 @@ Version 1.0 of the driver recommended adding `&charset=utf8` (alias for `SET NAM
 
 See http://dev.mysql.com/doc/refman/5.7/en/charset-unicode.html for more details on MySQL's Unicode support.
 
+## Context Support
+Since go1.8, context is introduced to `database/sql` for better control on timeout and cancellation.
+New interfaces such as `driver.QueryerContext`, `driver.ExecerContext` are introduced. See more details on [context support to database/sql package](https://golang.org/doc/go1.8#database_sql, "sql").
+
+In Go-MySQL-Driver, we implemented these interfaces for structs `mysqlConn`, `mysqlStmt` and `mysqlTx`.
 
 ## Testing / Development
 To run the driver tests you may need to adjust the configuration. See the [Testing Wiki-Page](https://github.com/go-sql-driver/mysql/wiki/Testing "Testing") for details.
diff --git a/connection.go b/connection.go
index cdce3e30f..2fd94c65b 100644
--- a/connection.go
+++ b/connection.go
@@ -42,7 +42,7 @@ func (mc *mysqlConn) handleParams() (err error) {
 			charsets := strings.Split(val, ",")
 			for i := range charsets {
 				// ignore errors here - a charset may not exist
-				err = mc.exec("SET NAMES " + charsets[i])
+				err = mc.exec(backgroundCtx(), "SET NAMES "+charsets[i])
 				if err == nil {
 					break
 				}
@@ -53,7 +53,7 @@ func (mc *mysqlConn) handleParams() (err error) {
 
 		// System Vars
 		default:
-			err = mc.exec("SET " + param + "=" + val + "")
+			err = mc.exec(backgroundCtx(), "SET "+param+"="+val+"")
 			if err != nil {
 				return
 			}
@@ -63,12 +63,17 @@ func (mc *mysqlConn) handleParams() (err error) {
 	return
 }
 
+// Begin implements driver.Conn interface
 func (mc *mysqlConn) Begin() (driver.Tx, error) {
+	return mc.beginTx(backgroundCtx(), txOptions{})
+}
+
+func (mc *mysqlConn) beginTx(ctx mysqlContext, opts txOptions) (driver.Tx, error) {
 	if mc.netConn == nil {
 		errLog.Print(ErrInvalidConn)
 		return nil, driver.ErrBadConn
 	}
-	err := mc.exec("START TRANSACTION")
+	err := mc.exec(ctx, "START TRANSACTION")
 	if err == nil {
 		return &mysqlTx{mc}, err
 	}
@@ -79,7 +84,7 @@ func (mc *mysqlConn) Begin() (driver.Tx, error) {
 func (mc *mysqlConn) Close() (err error) {
 	// Makes Close idempotent
 	if mc.netConn != nil {
-		err = mc.writeCommandPacket(comQuit)
+		err = mc.writeCommandPacket(backgroundCtx(), comQuit)
 	}
 
 	mc.cleanup()
@@ -104,12 +109,16 @@ func (mc *mysqlConn) cleanup() {
 }
 
 func (mc *mysqlConn) Prepare(query string) (driver.Stmt, error) {
+	return mc.prepareContext(backgroundCtx(), query)
+}
+
+func (mc *mysqlConn) prepareContext(ctx mysqlContext, query string) (driver.Stmt, error) {
 	if mc.netConn == nil {
 		errLog.Print(ErrInvalidConn)
 		return nil, driver.ErrBadConn
 	}
 	// Send command
-	err := mc.writeCommandPacketStr(comStmtPrepare, query)
+	err := mc.writeCommandPacketStr(ctx, comStmtPrepare, query)
 	if err != nil {
 		return nil, err
 	}
@@ -258,6 +267,10 @@ func (mc *mysqlConn) interpolateParams(query string, args []driver.Value) (strin
 }
 
 func (mc *mysqlConn) Exec(query string, args []driver.Value) (driver.Result, error) {
+	return mc.ExecContext(backgroundCtx(), query, args)
+}
+
+func (mc *mysqlConn) ExecContext(ctx mysqlContext, query string, args []driver.Value) (driver.Result, error) {
 	if mc.netConn == nil {
 		errLog.Print(ErrInvalidConn)
 		return nil, driver.ErrBadConn
@@ -276,7 +289,7 @@ func (mc *mysqlConn) Exec(query string, args []driver.Value) (driver.Result, err
 	mc.affectedRows = 0
 	mc.insertId = 0
 
-	err := mc.exec(query)
+	err := mc.exec(ctx, query)
 	if err == nil {
 		return &mysqlResult{
 			affectedRows: int64(mc.affectedRows),
@@ -287,9 +300,9 @@ func (mc *mysqlConn) Exec(query string, args []driver.Value) (driver.Result, err
 }
 
 // Internal function to execute commands
-func (mc *mysqlConn) exec(query string) error {
+func (mc *mysqlConn) exec(ctx mysqlContext, query string) error {
 	// Send command
-	if err := mc.writeCommandPacketStr(comQuery, query); err != nil {
+	if err := mc.writeCommandPacketStr(ctx, comQuery, query); err != nil {
 		return err
 	}
 
@@ -314,7 +327,12 @@ func (mc *mysqlConn) exec(query string) error {
 	return mc.discardResults()
 }
 
+// Query implements driver.Queryer interface
 func (mc *mysqlConn) Query(query string, args []driver.Value) (driver.Rows, error) {
+	return mc.queryContext(backgroundCtx(), query, args)
+}
+
+func (mc *mysqlConn) queryContext(ctx mysqlContext, query string, args []driver.Value) (driver.Rows, error) {
 	if mc.netConn == nil {
 		errLog.Print(ErrInvalidConn)
 		return nil, driver.ErrBadConn
@@ -331,7 +349,7 @@ func (mc *mysqlConn) Query(query string, args []driver.Value) (driver.Rows, erro
 		query = prepared
 	}
 	// Send command
-	err := mc.writeCommandPacketStr(comQuery, query)
+	err := mc.writeCommandPacketStr(ctx, comQuery, query)
 	if err == nil {
 		// Read Result
 		var resLen int
@@ -362,7 +380,7 @@ func (mc *mysqlConn) Query(query string, args []driver.Value) (driver.Rows, erro
 // The returned byte slice is only valid until the next read
 func (mc *mysqlConn) getSystemVar(name string) ([]byte, error) {
 	// Send command
-	if err := mc.writeCommandPacketStr(comQuery, "SELECT @@"+name); err != nil {
+	if err := mc.writeCommandPacketStr(backgroundCtx(), comQuery, "SELECT @@"+name); err != nil {
 		return nil, err
 	}
 
diff --git a/connection_ctx.go b/connection_ctx.go
new file mode 100644
index 000000000..866d61ee6
--- /dev/null
+++ b/connection_ctx.go
@@ -0,0 +1,48 @@
+// +build go1.8
+
+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"context"
+	"database/sql/driver"
+)
+
+// Ping implements driver.Pinger interface
+func (mc *mysqlConn) Ping(ctx context.Context) error {
+	if mc.netConn == nil {
+		errLog.Print(ErrInvalidConn)
+		return driver.ErrBadConn
+	}
+	if err := mc.writeCommandPacket(ctx, comPing); err != nil {
+		errLog.Print(err)
+		return err
+	}
+
+	if _, err := mc.readResultOK(); err != nil {
+		errLog.Print(err)
+		return err
+	}
+	return nil
+}
+
+// BeginTx implements driver.ConnBeginTx interface
+func (mc *mysqlConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
+	return mc.beginTx(ctx, txOptions(opts))
+}
+
+func (mc *mysqlConn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
+	return mc.prepareContext(ctx, query)
+}
+
+// QueryContext implements driver.QueryerContext interface
+func (mc *mysqlConn) QueryContext(ctx context.Context, query string, args []driver.Value) (driver.Rows, error) {
+	return mc.queryContext(ctx, query, args)
+}
diff --git a/ctx_backport.go b/ctx_backport.go
new file mode 100644
index 000000000..86826155c
--- /dev/null
+++ b/ctx_backport.go
@@ -0,0 +1,61 @@
+// +build !go1.8
+
+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"time"
+)
+
+// txOptions is defined for compatibility with Go 1.8's driver.TxOptions struct.
+type txOptions struct {
+	Isolation int
+	ReadOnly  bool
+}
+
+// mysqlContext is a copy of context.Context from Go 1.7 and later.
+type mysqlContext interface {
+	Deadline() (deadline time.Time, ok bool)
+
+	Done() <-chan struct{}
+
+	Err() error
+
+	Value(key interface{}) interface{}
+}
+
+// emptyCtx is copied from Go 1.7's context package.
+type emptyCtx int
+
+func (*emptyCtx) Deadline() (deadline time.Time, ok bool) {
+	return
+}
+
+func (*emptyCtx) Done() <-chan struct{} {
+	return nil
+}
+
+func (*emptyCtx) Err() error {
+	return nil
+}
+
+func (*emptyCtx) Value(key interface{}) interface{} {
+	return nil
+}
+
+func (e *emptyCtx) String() string {
+	return "context.Background"
+}
+
+var background = new(emptyCtx)
+
+func backgroundCtx() mysqlContext {
+	return background
+}
diff --git a/ctx_go18.go b/ctx_go18.go
new file mode 100644
index 000000000..60394dba6
--- /dev/null
+++ b/ctx_go18.go
@@ -0,0 +1,27 @@
+// +build go1.8
+
+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"context"
+	"database/sql/driver"
+)
+
+// The definitions below are for compatibility with older Go versions.
+// See ctx_backport.go for the definitions used in older Go versions.
+
+type txOptions driver.TxOptions
+
+type mysqlContext context.Context
+
+func backgroundCtx() mysqlContext {
+	return context.Background()
+}
diff --git a/driver.go b/driver.go
index e51d98a3c..5031206ce 100644
--- a/driver.go
+++ b/driver.go
@@ -14,6 +14,7 @@
 //  db, err := sql.Open("mysql", "user:password@/dbname")
 //
 // See https://github.com/go-sql-driver/mysql#usage for details
+
 package mysql
 
 import (
@@ -95,7 +96,7 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 	}
 
 	// Send Client Authentication Packet
-	if err = mc.writeAuthPacket(cipher); err != nil {
+	if err = mc.writeAuthPacket(backgroundCtx(), cipher); err != nil {
 		mc.cleanup()
 		return nil, err
 	}
@@ -157,7 +158,7 @@ func handleAuthResult(mc *mysqlConn, oldCipher []byte) error {
 			cipher = oldCipher
 		}
 
-		if err = mc.writeOldAuthPacket(cipher); err != nil {
+		if err = mc.writeOldAuthPacket(backgroundCtx(), cipher); err != nil {
 			return err
 		}
 		_, err = mc.readResultOK()
@@ -165,12 +166,12 @@ func handleAuthResult(mc *mysqlConn, oldCipher []byte) error {
 		// Retry with clear text password for
 		// http://dev.mysql.com/doc/refman/5.7/en/cleartext-authentication-plugin.html
 		// http://dev.mysql.com/doc/refman/5.7/en/pam-authentication-plugin.html
-		if err = mc.writeClearAuthPacket(); err != nil {
+		if err = mc.writeClearAuthPacket(backgroundCtx()); err != nil {
 			return err
 		}
 		_, err = mc.readResultOK()
 	} else if mc.cfg.AllowNativePasswords && err == ErrNativePassword {
-		if err = mc.writeNativeAuthPacket(cipher); err != nil {
+		if err = mc.writeNativeAuthPacket(backgroundCtx(), cipher); err != nil {
 			return err
 		}
 		_, err = mc.readResultOK()
diff --git a/driver_test.go b/driver_test.go
index 6cd9675d9..2e33a4edd 100644
--- a/driver_test.go
+++ b/driver_test.go
@@ -182,6 +182,14 @@ func TestEmptyQuery(t *testing.T) {
 	})
 }
 
+func (dbt *DBTest) TestPing(t *testing.T) {
+	runTests(t, dsn, func(dbt *DBTest) {
+		if err := dbt.db.Ping(); err != nil {
+			dbt.fail("Ping", "Ping", err)
+		}
+	})
+}
+
 func TestCRUD(t *testing.T) {
 	runTests(t, dsn, func(dbt *DBTest) {
 		// Create Table
diff --git a/infile.go b/infile.go
index 547357cfa..06b3237b7 100644
--- a/infile.go
+++ b/infile.go
@@ -93,7 +93,7 @@ func deferredClose(err *error, closer io.Closer) {
 	}
 }
 
-func (mc *mysqlConn) handleInFileRequest(name string) (err error) {
+func (mc *mysqlConn) handleInFileRequest(ctx mysqlContext, name string) (err error) {
 	var rdr io.Reader
 	var data []byte
 	packetSize := 16 * 1024 // 16KB is small enough for disk readahead and large enough for TCP
@@ -153,7 +153,7 @@ func (mc *mysqlConn) handleInFileRequest(name string) (err error) {
 		for err == nil {
 			n, err = rdr.Read(data[4:])
 			if n > 0 {
-				if ioErr := mc.writePacket(data[:4+n]); ioErr != nil {
+				if ioErr := mc.writePacket(ctx, data[:4+n]); ioErr != nil {
 					return ioErr
 				}
 			}
@@ -167,7 +167,7 @@ func (mc *mysqlConn) handleInFileRequest(name string) (err error) {
 	if data == nil {
 		data = make([]byte, 4)
 	}
-	if ioErr := mc.writePacket(data[:4]); ioErr != nil {
+	if ioErr := mc.writePacket(ctx, data[:4]); ioErr != nil {
 		return ioErr
 	}
 
diff --git a/packets.go b/packets.go
index cb21397a2..45461821f 100644
--- a/packets.go
+++ b/packets.go
@@ -83,7 +83,15 @@ func (mc *mysqlConn) readPacket() ([]byte, error) {
 }
 
 // Write packet buffer 'data'
-func (mc *mysqlConn) writePacket(data []byte) error {
+func (mc *mysqlConn) writePacket(ctx mysqlContext, data []byte) error {
+	if ctx == nil {
+		panic("context cannot be nil")
+	}
+	ctxDeadline, isCtxDeadlineSet := ctx.Deadline()
+	if isCtxDeadlineSet && !ctxDeadline.After(time.Now()) {
+		return errors.New("timeout")
+	}
+
 	pktLen := len(data) - 4
 
 	if pktLen > mc.maxAllowedPacket {
@@ -106,8 +114,16 @@ func (mc *mysqlConn) writePacket(data []byte) error {
 		data[3] = mc.sequence
 
 		// Write packet
+		var timeNow = time.Now()
+		var deadline = timeNow
 		if mc.writeTimeout > 0 {
-			if err := mc.netConn.SetWriteDeadline(time.Now().Add(mc.writeTimeout)); err != nil {
+			deadline = timeNow.Add(mc.writeTimeout)
+			if isCtxDeadlineSet && deadline.After(ctxDeadline) {
+				deadline = ctxDeadline
+			}
+		}
+		if deadline.After(timeNow) {
+			if err := mc.netConn.SetWriteDeadline(deadline); err != nil {
 				return err
 			}
 		}
@@ -223,7 +239,7 @@ func (mc *mysqlConn) readInitPacket() ([]byte, error) {
 
 // Client Authentication Packet
 // http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::HandshakeResponse
-func (mc *mysqlConn) writeAuthPacket(cipher []byte) error {
+func (mc *mysqlConn) writeAuthPacket(ctx mysqlContext, cipher []byte) error {
 	// Adjust client flags based on server support
 	clientFlags := clientProtocol41 |
 		clientSecureConn |
@@ -292,7 +308,7 @@ func (mc *mysqlConn) writeAuthPacket(cipher []byte) error {
 	// http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::SSLRequest
 	if mc.cfg.tls != nil {
 		// Send TLS / SSL request packet
-		if err := mc.writePacket(data[:(4+4+1+23)+4]); err != nil {
+		if err := mc.writePacket(ctx, data[:(4+4+1+23)+4]); err != nil {
 			return err
 		}
 
@@ -334,12 +350,12 @@ func (mc *mysqlConn) writeAuthPacket(cipher []byte) error {
 	data[pos] = 0x00
 
 	// Send Auth packet
-	return mc.writePacket(data)
+	return mc.writePacket(ctx, data)
 }
 
 //  Client old authentication packet
 // http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchResponse
-func (mc *mysqlConn) writeOldAuthPacket(cipher []byte) error {
+func (mc *mysqlConn) writeOldAuthPacket(ctx mysqlContext, cipher []byte) error {
 	// User password
 	scrambleBuff := scrambleOldPassword(cipher, []byte(mc.cfg.Passwd))
 
@@ -356,12 +372,12 @@ func (mc *mysqlConn) writeOldAuthPacket(cipher []byte) error {
 	copy(data[4:], scrambleBuff)
 	data[4+pktLen-1] = 0x00
 
-	return mc.writePacket(data)
+	return mc.writePacket(ctx, data)
 }
 
 //  Client clear text authentication packet
 // http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchResponse
-func (mc *mysqlConn) writeClearAuthPacket() error {
+func (mc *mysqlConn) writeClearAuthPacket(ctx mysqlContext) error {
 	// Calculate the packet length and add a tailing 0
 	pktLen := len(mc.cfg.Passwd) + 1
 	data := mc.buf.takeSmallBuffer(4 + pktLen)
@@ -375,12 +391,12 @@ func (mc *mysqlConn) writeClearAuthPacket() error {
 	copy(data[4:], mc.cfg.Passwd)
 	data[4+pktLen-1] = 0x00
 
-	return mc.writePacket(data)
+	return mc.writePacket(ctx, data)
 }
 
 //  Native password authentication method
 // http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchResponse
-func (mc *mysqlConn) writeNativeAuthPacket(cipher []byte) error {
+func (mc *mysqlConn) writeNativeAuthPacket(ctx mysqlContext, cipher []byte) error {
 	scrambleBuff := scramblePassword(cipher, []byte(mc.cfg.Passwd))
 
 	// Calculate the packet length and add a tailing 0
@@ -395,14 +411,14 @@ func (mc *mysqlConn) writeNativeAuthPacket(cipher []byte) error {
 	// Add the scramble
 	copy(data[4:], scrambleBuff)
 
-	return mc.writePacket(data)
+	return mc.writePacket(ctx, data)
 }
 
 /******************************************************************************
 *                             Command Packets                                 *
 ******************************************************************************/
 
-func (mc *mysqlConn) writeCommandPacket(command byte) error {
+func (mc *mysqlConn) writeCommandPacket(ctx mysqlContext, command byte) error {
 	// Reset Packet Sequence
 	mc.sequence = 0
 
@@ -417,10 +433,10 @@ func (mc *mysqlConn) writeCommandPacket(command byte) error {
 	data[4] = command
 
 	// Send CMD packet
-	return mc.writePacket(data)
+	return mc.writePacket(ctx, data)
 }
 
-func (mc *mysqlConn) writeCommandPacketStr(command byte, arg string) error {
+func (mc *mysqlConn) writeCommandPacketStr(ctx mysqlContext, command byte, arg string) error {
 	// Reset Packet Sequence
 	mc.sequence = 0
 
@@ -439,10 +455,10 @@ func (mc *mysqlConn) writeCommandPacketStr(command byte, arg string) error {
 	copy(data[5:], arg)
 
 	// Send CMD packet
-	return mc.writePacket(data)
+	return mc.writePacket(ctx, data)
 }
 
-func (mc *mysqlConn) writeCommandPacketUint32(command byte, arg uint32) error {
+func (mc *mysqlConn) writeCommandPacketUint32(ctx mysqlContext, command byte, arg uint32) error {
 	// Reset Packet Sequence
 	mc.sequence = 0
 
@@ -463,7 +479,7 @@ func (mc *mysqlConn) writeCommandPacketUint32(command byte, arg uint32) error {
 	data[8] = byte(arg >> 24)
 
 	// Send CMD packet
-	return mc.writePacket(data)
+	return mc.writePacket(ctx, data)
 }
 
 /******************************************************************************
@@ -525,7 +541,7 @@ func (mc *mysqlConn) readResultSetHeaderPacket() (int, error) {
 			return 0, mc.handleErrorPacket(data)
 
 		case iLocalInFile:
-			return 0, mc.handleInFileRequest(string(data[1:]))
+			return 0, mc.handleInFileRequest(backgroundCtx(), string(data[1:]))
 		}
 
 		// column count
@@ -823,7 +839,7 @@ func (stmt *mysqlStmt) readPrepareResultPacket() (uint16, error) {
 }
 
 // http://dev.mysql.com/doc/internals/en/com-stmt-send-long-data.html
-func (stmt *mysqlStmt) writeCommandLongData(paramID int, arg []byte) error {
+func (stmt *mysqlStmt) writeCommandLongData(ctx mysqlContext, paramID int, arg []byte) error {
 	maxLen := stmt.mc.maxAllowedPacket - 1
 	pktLen := maxLen
 
@@ -860,7 +876,7 @@ func (stmt *mysqlStmt) writeCommandLongData(paramID int, arg []byte) error {
 		data[10] = byte(paramID >> 8)
 
 		// Send CMD packet
-		err := stmt.mc.writePacket(data[:4+pktLen])
+		err := stmt.mc.writePacket(ctx, data[:4+pktLen])
 		if err == nil {
 			data = data[pktLen-dataOffset:]
 			continue
@@ -876,7 +892,7 @@ func (stmt *mysqlStmt) writeCommandLongData(paramID int, arg []byte) error {
 
 // Execute Prepared Statement
 // http://dev.mysql.com/doc/internals/en/com-stmt-execute.html
-func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
+func (stmt *mysqlStmt) writeExecutePacket(ctx mysqlContext, args []driver.Value) error {
 	if len(args) != stmt.paramCount {
 		return fmt.Errorf(
 			"argument count mismatch (got: %d; has: %d)",
@@ -1021,7 +1037,7 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 						)
 						paramValues = append(paramValues, v...)
 					} else {
-						if err := stmt.writeCommandLongData(i, v); err != nil {
+						if err := stmt.writeCommandLongData(ctx, i, v); err != nil {
 							return err
 						}
 					}
@@ -1043,7 +1059,7 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 					)
 					paramValues = append(paramValues, v...)
 				} else {
-					if err := stmt.writeCommandLongData(i, []byte(v)); err != nil {
+					if err := stmt.writeCommandLongData(ctx, i, []byte(v)); err != nil {
 						return err
 					}
 				}
@@ -1080,7 +1096,7 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 		data = data[:pos]
 	}
 
-	return mc.writePacket(data)
+	return mc.writePacket(ctx, data)
 }
 
 func (mc *mysqlConn) discardResults() error {
diff --git a/statement.go b/statement.go
index b88771674..d6285e5fd 100644
--- a/statement.go
+++ b/statement.go
@@ -23,6 +23,7 @@ type mysqlStmt struct {
 	columns    [][]mysqlField // cached from the first query
 }
 
+// Close implements driver.Conn interface
 func (stmt *mysqlStmt) Close() error {
 	if stmt.mc == nil || stmt.mc.netConn == nil {
 		// driver.Stmt.Close can be called more than once, thus this function
@@ -32,11 +33,12 @@ func (stmt *mysqlStmt) Close() error {
 		return driver.ErrBadConn
 	}
 
-	err := stmt.mc.writeCommandPacketUint32(comStmtClose, stmt.id)
+	err := stmt.mc.writeCommandPacketUint32(backgroundCtx(), comStmtClose, stmt.id)
 	stmt.mc = nil
 	return err
 }
 
+// NumInput implements driver.Stmt interface
 func (stmt *mysqlStmt) NumInput() int {
 	return stmt.paramCount
 }
@@ -45,13 +47,18 @@ func (stmt *mysqlStmt) ColumnConverter(idx int) driver.ValueConverter {
 	return converter{}
 }
 
+// Exec implements driver.Stmt interface
 func (stmt *mysqlStmt) Exec(args []driver.Value) (driver.Result, error) {
+	return stmt.execContext(backgroundCtx(), args)
+}
+
+func (stmt *mysqlStmt) execContext(ctx mysqlContext, args []driver.Value) (driver.Result, error) {
 	if stmt.mc.netConn == nil {
 		errLog.Print(ErrInvalidConn)
 		return nil, driver.ErrBadConn
 	}
 	// Send command
-	err := stmt.writeExecutePacket(args)
+	err := stmt.writeExecutePacket(ctx, args)
 	if err != nil {
 		return nil, err
 	}
@@ -89,13 +96,18 @@ func (stmt *mysqlStmt) Exec(args []driver.Value) (driver.Result, error) {
 	}, nil
 }
 
+// Query implements driver.Stmt interface
 func (stmt *mysqlStmt) Query(args []driver.Value) (driver.Rows, error) {
+	return stmt.queryContext(backgroundCtx(), args)
+}
+
+func (stmt *mysqlStmt) queryContext(ctx mysqlContext, args []driver.Value) (driver.Rows, error) {
 	if stmt.mc.netConn == nil {
 		errLog.Print(ErrInvalidConn)
 		return nil, driver.ErrBadConn
 	}
 	// Send command
-	err := stmt.writeExecutePacket(args)
+	err := stmt.writeExecutePacket(ctx, args)
 	if err != nil {
 		return nil, err
 	}
diff --git a/statement_ctx.go b/statement_ctx.go
new file mode 100644
index 000000000..8b2d1204d
--- /dev/null
+++ b/statement_ctx.go
@@ -0,0 +1,26 @@
+// +build go1.8
+
+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"context"
+	"database/sql/driver"
+)
+
+// ExecContent implements driver.StmtExecContext interface
+func (stmt *mysqlStmt) ExecContext(ctx context.Context, args []driver.Value) (driver.Result, error) {
+	return stmt.execContext(ctx, args)
+}
+
+// QueryContext implements driver.StmtQueryContext interface
+func (stmt *mysqlStmt) QueryContext(ctx context.Context, args []driver.Value) (driver.Rows, error) {
+	return stmt.queryContext(ctx, args)
+}
diff --git a/transaction.go b/transaction.go
index 33c749b35..55002c5f9 100644
--- a/transaction.go
+++ b/transaction.go
@@ -12,20 +12,22 @@ type mysqlTx struct {
 	mc *mysqlConn
 }
 
+// Commit implements driver.Tx interface
 func (tx *mysqlTx) Commit() (err error) {
 	if tx.mc == nil || tx.mc.netConn == nil {
 		return ErrInvalidConn
 	}
-	err = tx.mc.exec("COMMIT")
+	err = tx.mc.exec(backgroundCtx(), "COMMIT")
 	tx.mc = nil
 	return
 }
 
+// Rollback implements driver.Tx interface
 func (tx *mysqlTx) Rollback() (err error) {
 	if tx.mc == nil || tx.mc.netConn == nil {
 		return ErrInvalidConn
 	}
-	err = tx.mc.exec("ROLLBACK")
+	err = tx.mc.exec(backgroundCtx(), "ROLLBACK")
 	tx.mc = nil
 	return
 }

From 669fc71ffc29cdb8b344b9c9e0b4f383f8fd176a Mon Sep 17 00:00:00 2001
From: Evan Shaw <evan@vendhq.com>
Date: Tue, 9 May 2017 08:21:30 +1200
Subject: [PATCH 2/6] Use context.DeadlineExceeded error

---
 ctx_backport.go | 9 +++++++++
 ctx_go18.go     | 2 ++
 packets.go      | 5 +----
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/ctx_backport.go b/ctx_backport.go
index 86826155c..dba59acb3 100644
--- a/ctx_backport.go
+++ b/ctx_backport.go
@@ -59,3 +59,12 @@ var background = new(emptyCtx)
 func backgroundCtx() mysqlContext {
 	return background
 }
+
+var deadlineExceeded = deadlineExceededError{}
+
+// deadlineExceededError is copied from Go 1.7's context package.
+type deadlineExceededError struct{}
+
+func (deadlineExceededError) Error() string   { return "context deadline exceeded" }
+func (deadlineExceededError) Timeout() bool   { return true }
+func (deadlineExceededError) Temporary() bool { return true }
diff --git a/ctx_go18.go b/ctx_go18.go
index 60394dba6..0b8dcb9b7 100644
--- a/ctx_go18.go
+++ b/ctx_go18.go
@@ -25,3 +25,5 @@ type mysqlContext context.Context
 func backgroundCtx() mysqlContext {
 	return context.Background()
 }
+
+var deadlineExceeded = context.DeadlineExceeded
diff --git a/packets.go b/packets.go
index 45461821f..da6d9c15d 100644
--- a/packets.go
+++ b/packets.go
@@ -84,12 +84,9 @@ func (mc *mysqlConn) readPacket() ([]byte, error) {
 
 // Write packet buffer 'data'
 func (mc *mysqlConn) writePacket(ctx mysqlContext, data []byte) error {
-	if ctx == nil {
-		panic("context cannot be nil")
-	}
 	ctxDeadline, isCtxDeadlineSet := ctx.Deadline()
 	if isCtxDeadlineSet && !ctxDeadline.After(time.Now()) {
-		return errors.New("timeout")
+		return deadlineExceeded
 	}
 
 	pktLen := len(data) - 4

From 2abb4ae488413dc6c9fbe602e71f4acd8b279948 Mon Sep 17 00:00:00 2001
From: Evan Shaw <evan@vendhq.com>
Date: Tue, 9 May 2017 08:42:58 +1200
Subject: [PATCH 3/6] Add context support for reads

---
 buffer.go         | 16 ++++++++++-----
 connection.go     | 30 ++++++++++++++--------------
 connection_ctx.go |  2 +-
 driver.go         | 12 +++++------
 infile.go         |  4 ++--
 packets.go        | 51 ++++++++++++++++++++++++++---------------------
 packets_test.go   | 18 ++++++++---------
 rows.go           | 18 ++++++++---------
 statement.go      | 14 ++++++-------
 9 files changed, 88 insertions(+), 77 deletions(-)

diff --git a/buffer.go b/buffer.go
index 2001feacd..e23806fbb 100644
--- a/buffer.go
+++ b/buffer.go
@@ -38,7 +38,7 @@ func newBuffer(nc net.Conn) buffer {
 }
 
 // fill reads into the buffer until at least _need_ bytes are in it
-func (b *buffer) fill(need int) error {
+func (b *buffer) fill(ctx mysqlContext, need int) error {
 	n := b.length
 
 	// move existing data to the beginning
@@ -59,8 +59,14 @@ func (b *buffer) fill(need int) error {
 	b.idx = 0
 
 	for {
-		if b.timeout > 0 {
-			if err := b.nc.SetReadDeadline(time.Now().Add(b.timeout)); err != nil {
+		var deadline time.Time
+		if ctxDeadline, ok := ctx.Deadline(); ok {
+			deadline = ctxDeadline
+		} else if b.timeout > 0 {
+			deadline = time.Now().Add(b.timeout)
+		}
+		if !deadline.IsZero() {
+			if err := b.nc.SetReadDeadline(deadline); err != nil {
 				return err
 			}
 		}
@@ -91,10 +97,10 @@ func (b *buffer) fill(need int) error {
 
 // returns next N bytes from buffer.
 // The returned slice is only guaranteed to be valid until the next read
-func (b *buffer) readNext(need int) ([]byte, error) {
+func (b *buffer) readNext(ctx mysqlContext, need int) ([]byte, error) {
 	if b.length < need {
 		// refill
-		if err := b.fill(need); err != nil {
+		if err := b.fill(ctx, need); err != nil {
 			return nil, err
 		}
 	}
diff --git a/connection.go b/connection.go
index 2fd94c65b..f756ce8c3 100644
--- a/connection.go
+++ b/connection.go
@@ -128,16 +128,16 @@ func (mc *mysqlConn) prepareContext(ctx mysqlContext, query string) (driver.Stmt
 	}
 
 	// Read Result
-	columnCount, err := stmt.readPrepareResultPacket()
+	columnCount, err := stmt.readPrepareResultPacket(ctx)
 	if err == nil {
 		if stmt.paramCount > 0 {
-			if err = mc.readUntilEOF(); err != nil {
+			if err = mc.readUntilEOF(ctx); err != nil {
 				return nil, err
 			}
 		}
 
 		if columnCount > 0 {
-			err = mc.readUntilEOF()
+			err = mc.readUntilEOF(ctx)
 		}
 	}
 
@@ -307,24 +307,24 @@ func (mc *mysqlConn) exec(ctx mysqlContext, query string) error {
 	}
 
 	// Read Result
-	resLen, err := mc.readResultSetHeaderPacket()
+	resLen, err := mc.readResultSetHeaderPacket(ctx)
 	if err != nil {
 		return err
 	}
 
 	if resLen > 0 {
 		// columns
-		if err := mc.readUntilEOF(); err != nil {
+		if err := mc.readUntilEOF(ctx); err != nil {
 			return err
 		}
 
 		// rows
-		if err := mc.readUntilEOF(); err != nil {
+		if err := mc.readUntilEOF(ctx); err != nil {
 			return err
 		}
 	}
 
-	return mc.discardResults()
+	return mc.discardResults(ctx)
 }
 
 // Query implements driver.Queryer interface
@@ -353,7 +353,7 @@ func (mc *mysqlConn) queryContext(ctx mysqlContext, query string, args []driver.
 	if err == nil {
 		// Read Result
 		var resLen int
-		resLen, err = mc.readResultSetHeaderPacket()
+		resLen, err = mc.readResultSetHeaderPacket(ctx)
 		if err == nil {
 			rows := new(textRows)
 			rows.mc = mc
@@ -369,7 +369,7 @@ func (mc *mysqlConn) queryContext(ctx mysqlContext, query string, args []driver.
 				}
 			}
 			// Columns
-			rows.rs.columns, err = mc.readColumns(resLen)
+			rows.rs.columns, err = mc.readColumns(ctx, resLen)
 			return rows, err
 		}
 	}
@@ -378,14 +378,14 @@ func (mc *mysqlConn) queryContext(ctx mysqlContext, query string, args []driver.
 
 // Gets the value of the given MySQL System Variable
 // The returned byte slice is only valid until the next read
-func (mc *mysqlConn) getSystemVar(name string) ([]byte, error) {
+func (mc *mysqlConn) getSystemVar(ctx mysqlContext, name string) ([]byte, error) {
 	// Send command
-	if err := mc.writeCommandPacketStr(backgroundCtx(), comQuery, "SELECT @@"+name); err != nil {
+	if err := mc.writeCommandPacketStr(ctx, comQuery, "SELECT @@"+name); err != nil {
 		return nil, err
 	}
 
 	// Read Result
-	resLen, err := mc.readResultSetHeaderPacket()
+	resLen, err := mc.readResultSetHeaderPacket(ctx)
 	if err == nil {
 		rows := new(textRows)
 		rows.mc = mc
@@ -393,14 +393,14 @@ func (mc *mysqlConn) getSystemVar(name string) ([]byte, error) {
 
 		if resLen > 0 {
 			// Columns
-			if err := mc.readUntilEOF(); err != nil {
+			if err := mc.readUntilEOF(ctx); err != nil {
 				return nil, err
 			}
 		}
 
 		dest := make([]driver.Value, resLen)
-		if err = rows.readRow(dest); err == nil {
-			return dest[0].([]byte), mc.readUntilEOF()
+		if err = rows.readRow(ctx, dest); err == nil {
+			return dest[0].([]byte), mc.readUntilEOF(ctx)
 		}
 	}
 	return nil, err
diff --git a/connection_ctx.go b/connection_ctx.go
index 866d61ee6..a013ff9ea 100644
--- a/connection_ctx.go
+++ b/connection_ctx.go
@@ -26,7 +26,7 @@ func (mc *mysqlConn) Ping(ctx context.Context) error {
 		return err
 	}
 
-	if _, err := mc.readResultOK(); err != nil {
+	if _, err := mc.readResultOK(ctx); err != nil {
 		errLog.Print(err)
 		return err
 	}
diff --git a/driver.go b/driver.go
index 5031206ce..cf72c1a51 100644
--- a/driver.go
+++ b/driver.go
@@ -89,7 +89,7 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 	mc.writeTimeout = mc.cfg.WriteTimeout
 
 	// Reading Handshake Initialization Packet
-	cipher, err := mc.readInitPacket()
+	cipher, err := mc.readInitPacket(backgroundCtx())
 	if err != nil {
 		mc.cleanup()
 		return nil, err
@@ -114,7 +114,7 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 		mc.maxAllowedPacket = mc.cfg.MaxAllowedPacket
 	} else {
 		// Get max allowed packet size
-		maxap, err := mc.getSystemVar("max_allowed_packet")
+		maxap, err := mc.getSystemVar(backgroundCtx(), "max_allowed_packet")
 		if err != nil {
 			mc.Close()
 			return nil, err
@@ -137,7 +137,7 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 
 func handleAuthResult(mc *mysqlConn, oldCipher []byte) error {
 	// Read Result Packet
-	cipher, err := mc.readResultOK()
+	cipher, err := mc.readResultOK(backgroundCtx())
 	if err == nil {
 		return nil // auth successful
 	}
@@ -161,7 +161,7 @@ func handleAuthResult(mc *mysqlConn, oldCipher []byte) error {
 		if err = mc.writeOldAuthPacket(backgroundCtx(), cipher); err != nil {
 			return err
 		}
-		_, err = mc.readResultOK()
+		_, err = mc.readResultOK(backgroundCtx())
 	} else if mc.cfg.AllowCleartextPasswords && err == ErrCleartextPassword {
 		// Retry with clear text password for
 		// http://dev.mysql.com/doc/refman/5.7/en/cleartext-authentication-plugin.html
@@ -169,12 +169,12 @@ func handleAuthResult(mc *mysqlConn, oldCipher []byte) error {
 		if err = mc.writeClearAuthPacket(backgroundCtx()); err != nil {
 			return err
 		}
-		_, err = mc.readResultOK()
+		_, err = mc.readResultOK(backgroundCtx())
 	} else if mc.cfg.AllowNativePasswords && err == ErrNativePassword {
 		if err = mc.writeNativeAuthPacket(backgroundCtx(), cipher); err != nil {
 			return err
 		}
-		_, err = mc.readResultOK()
+		_, err = mc.readResultOK(backgroundCtx())
 	}
 	return err
 }
diff --git a/infile.go b/infile.go
index 06b3237b7..6f94cb738 100644
--- a/infile.go
+++ b/infile.go
@@ -173,10 +173,10 @@ func (mc *mysqlConn) handleInFileRequest(ctx mysqlContext, name string) (err err
 
 	// read OK packet
 	if err == nil {
-		_, err = mc.readResultOK()
+		_, err = mc.readResultOK(ctx)
 		return err
 	}
 
-	mc.readPacket()
+	mc.readPacket(ctx)
 	return err
 }
diff --git a/packets.go b/packets.go
index da6d9c15d..108930483 100644
--- a/packets.go
+++ b/packets.go
@@ -24,11 +24,16 @@ import (
 // http://dev.mysql.com/doc/internals/en/client-server-protocol.html
 
 // Read packet to buffer 'data'
-func (mc *mysqlConn) readPacket() ([]byte, error) {
+func (mc *mysqlConn) readPacket(ctx mysqlContext) ([]byte, error) {
+	ctxDeadline, isCtxDeadlineSet := ctx.Deadline()
+	if isCtxDeadlineSet && !ctxDeadline.After(time.Now()) {
+		return nil, deadlineExceeded
+	}
+
 	var prevData []byte
 	for {
 		// read packet header
-		data, err := mc.buf.readNext(4)
+		data, err := mc.buf.readNext(ctx, 4)
 		if err != nil {
 			errLog.Print(err)
 			mc.Close()
@@ -61,7 +66,7 @@ func (mc *mysqlConn) readPacket() ([]byte, error) {
 		}
 
 		// read packet body [pktLen bytes]
-		data, err = mc.buf.readNext(pktLen)
+		data, err = mc.buf.readNext(ctx, pktLen)
 		if err != nil {
 			errLog.Print(err)
 			mc.Close()
@@ -152,8 +157,8 @@ func (mc *mysqlConn) writePacket(ctx mysqlContext, data []byte) error {
 
 // Handshake Initialization Packet
 // http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::Handshake
-func (mc *mysqlConn) readInitPacket() ([]byte, error) {
-	data, err := mc.readPacket()
+func (mc *mysqlConn) readInitPacket(ctx mysqlContext) ([]byte, error) {
+	data, err := mc.readPacket(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -484,8 +489,8 @@ func (mc *mysqlConn) writeCommandPacketUint32(ctx mysqlContext, command byte, ar
 ******************************************************************************/
 
 // Returns error if Packet is not an 'Result OK'-Packet
-func (mc *mysqlConn) readResultOK() ([]byte, error) {
-	data, err := mc.readPacket()
+func (mc *mysqlConn) readResultOK(ctx mysqlContext) ([]byte, error) {
+	data, err := mc.readPacket(ctx)
 	if err == nil {
 		// packet indicator
 		switch data[0] {
@@ -526,8 +531,8 @@ func (mc *mysqlConn) readResultOK() ([]byte, error) {
 
 // Result Set Header Packet
 // http://dev.mysql.com/doc/internals/en/com-query-response.html#packet-ProtocolText::Resultset
-func (mc *mysqlConn) readResultSetHeaderPacket() (int, error) {
-	data, err := mc.readPacket()
+func (mc *mysqlConn) readResultSetHeaderPacket(ctx mysqlContext) (int, error) {
+	data, err := mc.readPacket(ctx)
 	if err == nil {
 		switch data[0] {
 
@@ -616,11 +621,11 @@ func (mc *mysqlConn) handleOkPacket(data []byte) error {
 
 // Read Packets as Field Packets until EOF-Packet or an Error appears
 // http://dev.mysql.com/doc/internals/en/com-query-response.html#packet-Protocol::ColumnDefinition41
-func (mc *mysqlConn) readColumns(count int) ([]mysqlField, error) {
+func (mc *mysqlConn) readColumns(ctx mysqlContext, count int) ([]mysqlField, error) {
 	columns := make([]mysqlField, count)
 
 	for i := 0; ; i++ {
-		data, err := mc.readPacket()
+		data, err := mc.readPacket(ctx)
 		if err != nil {
 			return nil, err
 		}
@@ -709,14 +714,14 @@ func (mc *mysqlConn) readColumns(count int) ([]mysqlField, error) {
 
 // Read Packets as Field Packets until EOF-Packet or an Error appears
 // http://dev.mysql.com/doc/internals/en/com-query-response.html#packet-ProtocolText::ResultsetRow
-func (rows *textRows) readRow(dest []driver.Value) error {
+func (rows *textRows) readRow(ctx mysqlContext, dest []driver.Value) error {
 	mc := rows.mc
 
 	if rows.rs.done {
 		return io.EOF
 	}
 
-	data, err := mc.readPacket()
+	data, err := mc.readPacket(ctx)
 	if err != nil {
 		return err
 	}
@@ -777,9 +782,9 @@ func (rows *textRows) readRow(dest []driver.Value) error {
 }
 
 // Reads Packets until EOF-Packet or an Error appears. Returns count of Packets read
-func (mc *mysqlConn) readUntilEOF() error {
+func (mc *mysqlConn) readUntilEOF(ctx mysqlContext) error {
 	for {
-		data, err := mc.readPacket()
+		data, err := mc.readPacket(ctx)
 		if err != nil {
 			return err
 		}
@@ -802,8 +807,8 @@ func (mc *mysqlConn) readUntilEOF() error {
 
 // Prepare Result Packets
 // http://dev.mysql.com/doc/internals/en/com-stmt-prepare-response.html
-func (stmt *mysqlStmt) readPrepareResultPacket() (uint16, error) {
-	data, err := stmt.mc.readPacket()
+func (stmt *mysqlStmt) readPrepareResultPacket(ctx mysqlContext) (uint16, error) {
+	data, err := stmt.mc.readPacket(ctx)
 	if err == nil {
 		// packet indicator [1 byte]
 		if data[0] != iOK {
@@ -1096,19 +1101,19 @@ func (stmt *mysqlStmt) writeExecutePacket(ctx mysqlContext, args []driver.Value)
 	return mc.writePacket(ctx, data)
 }
 
-func (mc *mysqlConn) discardResults() error {
+func (mc *mysqlConn) discardResults(ctx mysqlContext) error {
 	for mc.status&statusMoreResultsExists != 0 {
-		resLen, err := mc.readResultSetHeaderPacket()
+		resLen, err := mc.readResultSetHeaderPacket(ctx)
 		if err != nil {
 			return err
 		}
 		if resLen > 0 {
 			// columns
-			if err := mc.readUntilEOF(); err != nil {
+			if err := mc.readUntilEOF(ctx); err != nil {
 				return err
 			}
 			// rows
-			if err := mc.readUntilEOF(); err != nil {
+			if err := mc.readUntilEOF(ctx); err != nil {
 				return err
 			}
 		}
@@ -1117,8 +1122,8 @@ func (mc *mysqlConn) discardResults() error {
 }
 
 // http://dev.mysql.com/doc/internals/en/binary-protocol-resultset-row.html
-func (rows *binaryRows) readRow(dest []driver.Value) error {
-	data, err := rows.mc.readPacket()
+func (rows *binaryRows) readRow(ctx mysqlContext, dest []driver.Value) error {
+	data, err := rows.mc.readPacket(ctx)
 	if err != nil {
 		return err
 	}
diff --git a/packets_test.go b/packets_test.go
index b1d64f5c7..1263dcf68 100644
--- a/packets_test.go
+++ b/packets_test.go
@@ -96,7 +96,7 @@ func TestReadPacketSingleByte(t *testing.T) {
 
 	conn.data = []byte{0x01, 0x00, 0x00, 0x00, 0xff}
 	conn.maxReads = 1
-	packet, err := mc.readPacket()
+	packet, err := mc.readPacket(backgroundCtx())
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -118,7 +118,7 @@ func TestReadPacketWrongSequenceID(t *testing.T) {
 	conn.data = []byte{0x01, 0x00, 0x00, 0x00, 0xff}
 	conn.maxReads = 1
 	mc.sequence = 1
-	_, err := mc.readPacket()
+	_, err := mc.readPacket(backgroundCtx())
 	if err != ErrPktSync {
 		t.Errorf("expected ErrPktSync, got %v", err)
 	}
@@ -130,7 +130,7 @@ func TestReadPacketWrongSequenceID(t *testing.T) {
 
 	// too high sequence id
 	conn.data = []byte{0x01, 0x00, 0x00, 0x42, 0xff}
-	_, err = mc.readPacket()
+	_, err = mc.readPacket(backgroundCtx())
 	if err != ErrPktSyncMul {
 		t.Errorf("expected ErrPktSyncMul, got %v", err)
 	}
@@ -166,7 +166,7 @@ func TestReadPacketSplit(t *testing.T) {
 
 	conn.data = data
 	conn.maxReads = 3
-	packet, err := mc.readPacket()
+	packet, err := mc.readPacket(backgroundCtx())
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -200,7 +200,7 @@ func TestReadPacketSplit(t *testing.T) {
 	conn.reads = 0
 	conn.maxReads = 5
 	mc.sequence = 0
-	packet, err = mc.readPacket()
+	packet, err = mc.readPacket(backgroundCtx())
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -226,7 +226,7 @@ func TestReadPacketSplit(t *testing.T) {
 	conn.reads = 0
 	conn.maxReads = 4
 	mc.sequence = 0
-	packet, err = mc.readPacket()
+	packet, err = mc.readPacket(backgroundCtx())
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -250,7 +250,7 @@ func TestReadPacketFail(t *testing.T) {
 	// illegal empty (stand-alone) packet
 	conn.data = []byte{0x00, 0x00, 0x00, 0x00}
 	conn.maxReads = 1
-	_, err := mc.readPacket()
+	_, err := mc.readPacket(backgroundCtx())
 	if err != driver.ErrBadConn {
 		t.Errorf("expected ErrBadConn, got %v", err)
 	}
@@ -262,7 +262,7 @@ func TestReadPacketFail(t *testing.T) {
 
 	// fail to read header
 	conn.closed = true
-	_, err = mc.readPacket()
+	_, err = mc.readPacket(backgroundCtx())
 	if err != driver.ErrBadConn {
 		t.Errorf("expected ErrBadConn, got %v", err)
 	}
@@ -275,7 +275,7 @@ func TestReadPacketFail(t *testing.T) {
 
 	// fail to read body
 	conn.maxReads = 1
-	_, err = mc.readPacket()
+	_, err = mc.readPacket(backgroundCtx())
 	if err != driver.ErrBadConn {
 		t.Errorf("expected ErrBadConn, got %v", err)
 	}
diff --git a/rows.go b/rows.go
index 900f548ae..2a6ffae78 100644
--- a/rows.go
+++ b/rows.go
@@ -74,10 +74,10 @@ func (rows *mysqlRows) Close() (err error) {
 
 	// Remove unread packets from stream
 	if !rows.rs.done {
-		err = mc.readUntilEOF()
+		err = mc.readUntilEOF(backgroundCtx())
 	}
 	if err == nil {
-		if err = mc.discardResults(); err != nil {
+		if err = mc.discardResults(backgroundCtx()); err != nil {
 			return err
 		}
 	}
@@ -103,7 +103,7 @@ func (rows *mysqlRows) nextResultSet() (int, error) {
 
 	// Remove unread packets from stream
 	if !rows.rs.done {
-		if err := rows.mc.readUntilEOF(); err != nil {
+		if err := rows.mc.readUntilEOF(backgroundCtx()); err != nil {
 			return 0, err
 		}
 		rows.rs.done = true
@@ -114,7 +114,7 @@ func (rows *mysqlRows) nextResultSet() (int, error) {
 		return 0, io.EOF
 	}
 	rows.rs = resultSet{}
-	return rows.mc.readResultSetHeaderPacket()
+	return rows.mc.readResultSetHeaderPacket(backgroundCtx())
 }
 
 func (rows *mysqlRows) nextNotEmptyResultSet() (int, error) {
@@ -140,11 +140,11 @@ func (rows *binaryRows) NextResultSet() (err error) {
 
 	// get columns, if not cached, read them and cache them.
 	if rows.i >= len(*rows.stmtCols) {
-		rows.rs.columns, err = rows.mc.readColumns(resLen)
+		rows.rs.columns, err = rows.mc.readColumns(backgroundCtx(), resLen)
 		*rows.stmtCols = append(*rows.stmtCols, rows.rs.columns)
 	} else {
 		rows.rs.columns = (*rows.stmtCols)[rows.i]
-		if err := rows.mc.readUntilEOF(); err != nil {
+		if err := rows.mc.readUntilEOF(backgroundCtx()); err != nil {
 			return err
 		}
 	}
@@ -160,7 +160,7 @@ func (rows *binaryRows) Next(dest []driver.Value) error {
 		}
 
 		// Fetch next row from stream
-		return rows.readRow(dest)
+		return rows.readRow(backgroundCtx(), dest)
 	}
 	return io.EOF
 }
@@ -171,7 +171,7 @@ func (rows *textRows) NextResultSet() (err error) {
 		return err
 	}
 
-	rows.rs.columns, err = rows.mc.readColumns(resLen)
+	rows.rs.columns, err = rows.mc.readColumns(backgroundCtx(), resLen)
 	return err
 }
 
@@ -182,7 +182,7 @@ func (rows *textRows) Next(dest []driver.Value) error {
 		}
 
 		// Fetch next row from stream
-		return rows.readRow(dest)
+		return rows.readRow(backgroundCtx(), dest)
 	}
 	return io.EOF
 }
diff --git a/statement.go b/statement.go
index d6285e5fd..1f05c6c89 100644
--- a/statement.go
+++ b/statement.go
@@ -69,24 +69,24 @@ func (stmt *mysqlStmt) execContext(ctx mysqlContext, args []driver.Value) (drive
 	mc.insertId = 0
 
 	// Read Result
-	resLen, err := mc.readResultSetHeaderPacket()
+	resLen, err := mc.readResultSetHeaderPacket(ctx)
 	if err != nil {
 		return nil, err
 	}
 
 	if resLen > 0 {
 		// Columns
-		if err = mc.readUntilEOF(); err != nil {
+		if err = mc.readUntilEOF(ctx); err != nil {
 			return nil, err
 		}
 
 		// Rows
-		if err := mc.readUntilEOF(); err != nil {
+		if err := mc.readUntilEOF(ctx); err != nil {
 			return nil, err
 		}
 	}
 
-	if err := mc.discardResults(); err != nil {
+	if err := mc.discardResults(ctx); err != nil {
 		return nil, err
 	}
 
@@ -115,7 +115,7 @@ func (stmt *mysqlStmt) queryContext(ctx mysqlContext, args []driver.Value) (driv
 	mc := stmt.mc
 
 	// Read Result
-	resLen, err := mc.readResultSetHeaderPacket()
+	resLen, err := mc.readResultSetHeaderPacket(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -129,11 +129,11 @@ func (stmt *mysqlStmt) queryContext(ctx mysqlContext, args []driver.Value) (driv
 		// Columns
 		// If not cached, read them and cache them
 		if len(stmt.columns) == 0 {
-			rows.rs.columns, err = mc.readColumns(resLen)
+			rows.rs.columns, err = mc.readColumns(ctx, resLen)
 			stmt.columns = append(stmt.columns, rows.rs.columns)
 		} else {
 			rows.rs.columns = stmt.columns[0]
-			err = mc.readUntilEOF()
+			err = mc.readUntilEOF(ctx)
 		}
 	} else {
 		rows.rs.done = true

From 691ec98f74ff25424017959038202780ee5e847d Mon Sep 17 00:00:00 2001
From: Evan Shaw <evan@vendhq.com>
Date: Tue, 9 May 2017 08:44:17 +1200
Subject: [PATCH 4/6] Rework write deadline logic

---
 packets.go | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/packets.go b/packets.go
index 108930483..64703a131 100644
--- a/packets.go
+++ b/packets.go
@@ -116,15 +116,13 @@ func (mc *mysqlConn) writePacket(ctx mysqlContext, data []byte) error {
 		data[3] = mc.sequence
 
 		// Write packet
-		var timeNow = time.Now()
-		var deadline = timeNow
-		if mc.writeTimeout > 0 {
-			deadline = timeNow.Add(mc.writeTimeout)
-			if isCtxDeadlineSet && deadline.After(ctxDeadline) {
-				deadline = ctxDeadline
-			}
+		var deadline time.Time
+		if ctxDeadline, ok := ctx.Deadline(); ok {
+			deadline = ctxDeadline
+		} else if mc.writeTimeout > 0 {
+			deadline = time.Now().Add(mc.writeTimeout)
 		}
-		if deadline.After(timeNow) {
+		if !deadline.IsZero() {
 			if err := mc.netConn.SetWriteDeadline(deadline); err != nil {
 				return err
 			}

From 6d7e8045352814ac0fe0de0f24b5545726f18cac Mon Sep 17 00:00:00 2001
From: Evan Shaw <evan@vendhq.com>
Date: Thu, 11 May 2017 08:39:10 +1200
Subject: [PATCH 5/6] README improvements

---
 README.md | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index ea08db9c4..5fe55198c 100644
--- a/README.md
+++ b/README.md
@@ -419,10 +419,9 @@ Version 1.0 of the driver recommended adding `&charset=utf8` (alias for `SET NAM
 See http://dev.mysql.com/doc/refman/5.7/en/charset-unicode.html for more details on MySQL's Unicode support.
 
 ## Context Support
-Since go1.8, context is introduced to `database/sql` for better control on timeout and cancellation.
-New interfaces such as `driver.QueryerContext`, `driver.ExecerContext` are introduced. See more details on [context support to database/sql package](https://golang.org/doc/go1.8#database_sql, "sql").
-
-In Go-MySQL-Driver, we implemented these interfaces for structs `mysqlConn`, `mysqlStmt` and `mysqlTx`.
+Go 1.8 added some `database/sql` methods that accept a `context.Context` parameter for better control over timeout and cancellation.
+See more details on [context support to database/sql package](https://golang.org/doc/go1.8#database_sql, "sql").
+Go-MySQL-Driver supports context deadlines, but not cancellation.
 
 ## Testing / Development
 To run the driver tests you may need to adjust the configuration. See the [Testing Wiki-Page](https://github.com/go-sql-driver/mysql/wiki/Testing "Testing") for details.

From ce38c4f00c087c0452ce17012e8f69065792d36b Mon Sep 17 00:00:00 2001
From: Evan Shaw <evan@vendhq.com>
Date: Sat, 13 May 2017 21:29:46 +1200
Subject: [PATCH 6/6] Add compile-time interface tests and fix method
 signatures

---
 connection.go          |  4 ++--
 connection_ctx.go      | 29 +++++++++++++++++++++++++++--
 connection_ctx_test.go | 23 +++++++++++++++++++++++
 statement_ctx.go       | 16 ++++++++++++----
 statement_ctx_test.go  | 20 ++++++++++++++++++++
 5 files changed, 84 insertions(+), 8 deletions(-)
 create mode 100644 connection_ctx_test.go
 create mode 100644 statement_ctx_test.go

diff --git a/connection.go b/connection.go
index f756ce8c3..5379abccd 100644
--- a/connection.go
+++ b/connection.go
@@ -267,10 +267,10 @@ func (mc *mysqlConn) interpolateParams(query string, args []driver.Value) (strin
 }
 
 func (mc *mysqlConn) Exec(query string, args []driver.Value) (driver.Result, error) {
-	return mc.ExecContext(backgroundCtx(), query, args)
+	return mc.execContext(backgroundCtx(), query, args)
 }
 
-func (mc *mysqlConn) ExecContext(ctx mysqlContext, query string, args []driver.Value) (driver.Result, error) {
+func (mc *mysqlConn) execContext(ctx mysqlContext, query string, args []driver.Value) (driver.Result, error) {
 	if mc.netConn == nil {
 		errLog.Print(ErrInvalidConn)
 		return nil, driver.ErrBadConn
diff --git a/connection_ctx.go b/connection_ctx.go
index a013ff9ea..98d8b02f2 100644
--- a/connection_ctx.go
+++ b/connection_ctx.go
@@ -13,6 +13,7 @@ package mysql
 import (
 	"context"
 	"database/sql/driver"
+	"errors"
 )
 
 // Ping implements driver.Pinger interface
@@ -43,6 +44,30 @@ func (mc *mysqlConn) PrepareContext(ctx context.Context, query string) (driver.S
 }
 
 // QueryContext implements driver.QueryerContext interface
-func (mc *mysqlConn) QueryContext(ctx context.Context, query string, args []driver.Value) (driver.Rows, error) {
-	return mc.queryContext(ctx, query, args)
+func (mc *mysqlConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
+	values, err := namedValueToValue(args)
+	if err != nil {
+		return nil, err
+	}
+	return mc.queryContext(ctx, query, values)
+}
+
+// ExecContext implements driver.ExecerContext interface
+func (mc *mysqlConn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
+	values, err := namedValueToValue(args)
+	if err != nil {
+		return nil, err
+	}
+	return mc.execContext(ctx, query, values)
+}
+
+func namedValueToValue(named []driver.NamedValue) ([]driver.Value, error) {
+	dargs := make([]driver.Value, len(named))
+	for n, param := range named {
+		if len(param.Name) > 0 {
+			return nil, errors.New("mysql: Named Parameters are not supported")
+		}
+		dargs[n] = param.Value
+	}
+	return dargs, nil
 }
diff --git a/connection_ctx_test.go b/connection_ctx_test.go
new file mode 100644
index 000000000..465f3fcef
--- /dev/null
+++ b/connection_ctx_test.go
@@ -0,0 +1,23 @@
+// +build go1.8
+
+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.package mysql
+
+package mysql
+
+import (
+	"database/sql/driver"
+)
+
+var (
+	_ driver.ConnBeginTx        = &mysqlConn{}
+	_ driver.ConnPrepareContext = &mysqlConn{}
+	_ driver.ExecerContext      = &mysqlConn{}
+	_ driver.Pinger             = &mysqlConn{}
+	_ driver.QueryerContext     = &mysqlConn{}
+)
diff --git a/statement_ctx.go b/statement_ctx.go
index 8b2d1204d..89c600cd6 100644
--- a/statement_ctx.go
+++ b/statement_ctx.go
@@ -16,11 +16,19 @@ import (
 )
 
 // ExecContent implements driver.StmtExecContext interface
-func (stmt *mysqlStmt) ExecContext(ctx context.Context, args []driver.Value) (driver.Result, error) {
-	return stmt.execContext(ctx, args)
+func (stmt *mysqlStmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
+	values, err := namedValueToValue(args)
+	if err != nil {
+		return nil, err
+	}
+	return stmt.execContext(ctx, values)
 }
 
 // QueryContext implements driver.StmtQueryContext interface
-func (stmt *mysqlStmt) QueryContext(ctx context.Context, args []driver.Value) (driver.Rows, error) {
-	return stmt.queryContext(ctx, args)
+func (stmt *mysqlStmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
+	values, err := namedValueToValue(args)
+	if err != nil {
+		return nil, err
+	}
+	return stmt.queryContext(ctx, values)
 }
diff --git a/statement_ctx_test.go b/statement_ctx_test.go
new file mode 100644
index 000000000..60eeeef18
--- /dev/null
+++ b/statement_ctx_test.go
@@ -0,0 +1,20 @@
+// +build go1.8
+
+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.package mysql
+
+package mysql
+
+import (
+	"database/sql/driver"
+)
+
+var (
+	_ driver.StmtExecContext  = &mysqlStmt{}
+	_ driver.StmtQueryContext = &mysqlStmt{}
+)