tcp: ignore ENOPROTOOPT returned by SetKeepAlive on some platforms

Signed-off-by: Achille Roussel <[email protected]>

connector.go

@@ -11,11 +11,13 @@ package mysql
 import (
  "context"
  "database/sql/driver"
+ "errors"
  "fmt"
  "net"
  "os"
  "strconv"
  "strings"
+ "syscall"
 )
 
 type connector struct {
@@ -98,13 +100,11 @@ func (c *connector) Connect(ctx context.Context) (driver.Conn, error) {
  }
 
  // Enable TCP Keepalives on TCP connections
- if tc, ok := mc.netConn.(*net.TCPConn); ok {
- if err := tc.SetKeepAlive(true); err != nil {
- // Don't send COM_QUIT before handshake.
- mc.netConn.Close()
- mc.netConn = nil
- return nil, err
- }
+ if err := enableKeepAlive(mc.netConn); err != nil {
+ // Don't send COM_QUIT before handshake.
+ mc.netConn.Close()
+ mc.netConn = nil
+ return nil, err
  }
 
  // Call startWatcher for context support (From Go 1.8)
@@ -188,3 +188,18 @@ func (c *connector) Connect(ctx context.Context) (driver.Conn, error) {
 func (c *connector) Driver() driver.Driver {
  return &MySQLDriver{}
 }
+
+func enableKeepAlive(nc net.Conn) error {
+ if tc, ok := nc.(*net.TCPConn); ok {
+ if err := tc.SetKeepAlive(true); err != nil {
+ // The underlying setsockopt syscall may return ENOPROTOOPT if the
+ // system does not support TCP keep-alive. We can still successfully
+ // use the driver without keep-alive support, which is why we choose
+ // to silence it here.
+ if !errors.Is(err, syscall.ENOPROTOOPT) {
+ return err
+ }
+ }
+ }
+ return nil
+}