net, backend: add more error types to disconnection error (#490)

Author: djshow832

pkg/proxy/backend/error.go

@@ -99,7 +99,7 @@ func Error2Source(err error) ErrorSource {
 		return SrcNone
 	}
 	// Disconnection errors may come from other errors such as ErrProxyNoBackend and ErrBackendHandshake.
-	// ErrClientConn and ErrBackendConn may include non-connection errors.
+	// ErrClientConn and ErrBackendConn may include non-connection errors such as wrong PPV2 format, TLS cert error.
 	if pnet.IsDisconnectError(err) {
 		if errors.Is(err, ErrClientConn) {
 			return SrcClientNetwork

pkg/proxy/net/error.go

@@ -4,6 +4,11 @@
 package net
 
 import (
+	"context"
+	"io"
+	"os"
+	"syscall"
+
 	"github.com/pingcap/tiproxy/lib/util/errors"
 )
 
@@ -15,3 +20,15 @@ var (
 	ErrCloseConn    = errors.New("failed to close the connection")
 	ErrHandshakeTLS = errors.New("failed to complete tls handshake")
 )
+
+// IsDisconnectError returns whether the error is caused by peer disconnection.
+func IsDisconnectError(err error) bool {
+	switch {
+	// Do not use os.Timeout(err) because it doesn't unwrap the error.
+	case errors.Is(err, io.EOF), errors.Is(err, syscall.EPIPE), errors.Is(err, syscall.ECONNRESET),
+		errors.Is(err, syscall.ECONNABORTED), errors.Is(err, syscall.ETIMEDOUT), errors.Is(err, os.ErrDeadlineExceeded),
+		errors.Is(err, context.DeadlineExceeded):
+		return true
+	}
+	return false
+}

pkg/proxy/net/error_test.go

@@ -0,0 +1,35 @@
+// Copyright 2024 PingCAP, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+package net
+
+import (
+	"context"
+	"os"
+	"syscall"
+	"testing"
+
+	"github.com/pingcap/tiproxy/lib/util/errors"
+	"github.com/stretchr/testify/require"
+)
+
+func TestIsDisconnectErr(t *testing.T) {
+	disConnErrors := []error{
+		syscall.ETIMEDOUT,
+		os.ErrDeadlineExceeded,
+		context.DeadlineExceeded,
+		errors.Wrap(errors.New("mock"), syscall.ETIMEDOUT),
+		errors.Wrap(syscall.ETIMEDOUT, errors.New("mock")),
+	}
+	for _, err := range disConnErrors {
+		require.True(t, IsDisconnectError(err))
+	}
+
+	otherErrors := []error{
+		syscall.ENOENT,
+		errors.New("mock"),
+	}
+	for _, err := range otherErrors {
+		require.False(t, IsDisconnectError(err))
+	}
+}

pkg/proxy/net/net_err.go

@@ -182,7 +182,7 @@ func ReadFull(prw packetReadWriter, b []byte) error {
 	for n := 0; n < m; {
 		nn, err := prw.Read(b[n:])
 		if err != nil {
-			return errors.WithStack(err)
+			return err
 		}
 		n += nn
 	}
@@ -220,7 +220,7 @@ func (p *PacketIO) ApplyOpts(opts ...PacketIOption) {
 }
 
 func (p *PacketIO) wrapErr(err error) error {
-	return errors.WithStack(errors.Wrap(p.wrap, err))
+	return errors.Wrap(p.wrap, err)
 }
 
 func (p *PacketIO) LocalAddr() net.Addr {
@@ -371,7 +371,7 @@ func (p *PacketIO) ForwardUntil(dest *PacketIO, isEnd func(firstByte byte, first
 					break
 				}
 				if header, err = p.readWriter.Peek(4); err != nil {
-					return p.wrapErr(errors.Wrap(ErrReadConn, err))
+					return p.wrapErr(errors.Wrap(ErrReadConn, errors.WithStack(err)))
 				}
 				length = int(header[0]) | int(header[1])<<8 | int(header[2])<<16
 			}
@@ -405,7 +405,7 @@ func (p *PacketIO) OutPackets() uint64 {
 
 func (p *PacketIO) Flush() error {
 	if err := p.readWriter.Flush(); err != nil {
-		return p.wrapErr(errors.Wrap(ErrFlushConn, err))
+		return p.wrapErr(errors.Wrap(ErrFlushConn, errors.WithStack(err)))
 	}
 	return nil
 }
@@ -443,7 +443,7 @@ func (p *PacketIO) Close() error {
 		}
 	*/
 	if err := p.readWriter.Close(); err != nil && !errors.Is(err, net.ErrClosed) {
-		errs = append(errs, err)
+		errs = append(errs, errors.WithStack(err))
 	}
 	return p.wrapErr(errors.Collect(ErrCloseConn, errs...))
 }

pkg/proxy/net/packetio.go

@@ -28,7 +28,7 @@ func (p *PacketIO) ServerTLSHandshake(tlsConfig *tls.Config) (tls.ConnectionStat
 	conn := &tlsInternalConn{p.readWriter}
 	tlsConn := tls.Server(conn, tlsConfig)
 	if err := tlsConn.Handshake(); err != nil {
-		return tls.ConnectionState{}, p.wrapErr(errors.Wrap(ErrHandshakeTLS, err))
+		return tls.ConnectionState{}, p.wrapErr(errors.Wrap(ErrHandshakeTLS, errors.WithStack(err)))
 	}
 	p.readWriter = newTLSReadWriter(p.readWriter, tlsConn)
 	return tlsConn.ConnectionState(), nil
@@ -39,7 +39,7 @@ func (p *PacketIO) ClientTLSHandshake(tlsConfig *tls.Config) error {
 	conn := &tlsInternalConn{p.readWriter}
 	tlsConn := tls.Client(conn, tlsConfig)
 	if err := tlsConn.Handshake(); err != nil {
-		return p.wrapErr(errors.Wrap(ErrHandshakeTLS, err))
+		return p.wrapErr(errors.Wrap(ErrHandshakeTLS, errors.WithStack(err)))
 	}
 	p.readWriter = newTLSReadWriter(p.readWriter, tlsConn)
 	return nil