From 6f11e928014636fe78f65814a25cbffcbb33b75f Mon Sep 17 00:00:00 2001
From: Christian Schwarz <me@cschwarz.com>
Date: Mon, 20 Sep 2021 07:43:22 +0200
Subject: [PATCH] stderr debugging for #517 (tls: bad certificate)

refs #517

cc @asomers
---
 rpc/transportmux/transportmux.go                            | 3 +++
 rpc/versionhandshake/versionhandshake.go                    | 4 ++++
 rpc/versionhandshake/versionhandshake_transport_wrappers.go | 3 +++
 transport/tls/connect_tls.go                                | 3 +++
 transport/tls/serve_tls.go                                  | 3 +++
 5 files changed, 16 insertions(+)

diff --git a/rpc/transportmux/transportmux.go b/rpc/transportmux/transportmux.go
index a35c9a8..34b3bbe 100644
--- a/rpc/transportmux/transportmux.go
+++ b/rpc/transportmux/transportmux.go
@@ -7,6 +7,7 @@ package transportmux
 
 import (
 	"context"
+	"os"
 	"sync/atomic"
 	"syscall"
 
@@ -15,6 +16,7 @@ import (
 	"net"
 	"time"
 
+	"github.com/kr/pretty"
 	"github.com/zrepl/zrepl/daemon/logging"
 	"github.com/zrepl/zrepl/logger"
 	"github.com/zrepl/zrepl/transport"
@@ -151,6 +153,7 @@ func Demux(ctx context.Context, rawListener transport.AuthenticatedListener, lab
 
 			rawConn, err := rawListener.Accept(ctx)
 			if err != nil {
+				fmt.Fprintf(os.Stderr, "transportmux.Demux: rawListener.Accept() returned error: %T %s\n%s\n", err, err, pretty.Sprint(err))
 				if ctx.Err() != nil {
 					return
 				}
diff --git a/rpc/versionhandshake/versionhandshake.go b/rpc/versionhandshake/versionhandshake.go
index 749535a..f8d3949 100644
--- a/rpc/versionhandshake/versionhandshake.go
+++ b/rpc/versionhandshake/versionhandshake.go
@@ -10,9 +10,12 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"os"
 	"strings"
 	"time"
 	"unicode/utf8"
+
+	"github.com/kr/pretty"
 )
 
 type HandshakeMessage struct {
@@ -93,6 +96,7 @@ func (m *HandshakeMessage) Encode() ([]byte, error) {
 func (m *HandshakeMessage) DecodeReader(r io.Reader, maxLen int) error {
 	var lenAndSpace [11]byte
 	if _, err := io.ReadFull(r, lenAndSpace[:]); err != nil {
+		fmt.Fprintf(os.Stderr, "HandshakeMessage.DecodeReader error: %T\n%s", err, pretty.Sprint(err))
 		return hsIOErr(err, "error reading protocol banner length: %s", err)
 	}
 	if !utf8.Valid(lenAndSpace[:]) {
diff --git a/rpc/versionhandshake/versionhandshake_transport_wrappers.go b/rpc/versionhandshake/versionhandshake_transport_wrappers.go
index bc176dd..be6e64a 100644
--- a/rpc/versionhandshake/versionhandshake_transport_wrappers.go
+++ b/rpc/versionhandshake/versionhandshake_transport_wrappers.go
@@ -2,7 +2,9 @@ package versionhandshake
 
 import (
 	"context"
+	"fmt"
 	"net"
+	"os"
 	"time"
 
 	"github.com/zrepl/zrepl/transport"
@@ -23,6 +25,7 @@ func (c HandshakeConnecter) Connect(ctx context.Context) (transport.Wire, error)
 		dl = time.Now().Add(c.timeout)
 	}
 	if err := DoHandshakeCurrentVersion(conn, dl); err != nil {
+		fmt.Fprintf(os.Stderr, "HandshakeConnecter error: %T\n\t%s\n\t%v\n\t%#v\n\n", err, err, err, err)
 		conn.Close()
 		return nil, err
 	}
diff --git a/transport/tls/connect_tls.go b/transport/tls/connect_tls.go
index 4fc76f9..931bd25 100644
--- a/transport/tls/connect_tls.go
+++ b/transport/tls/connect_tls.go
@@ -3,7 +3,9 @@ package tls
 import (
 	"context"
 	"crypto/tls"
+	"fmt"
 	"net"
+	"os"
 
 	"github.com/pkg/errors"
 
@@ -48,6 +50,7 @@ func TLSConnecterFromConfig(in *config.TLSConnect) (*TLSConnecter, error) {
 func (c *TLSConnecter) Connect(dialCtx context.Context) (transport.Wire, error) {
 	conn, err := c.dialer.DialContext(dialCtx, "tcp", c.Address)
 	if err != nil {
+		fmt.Fprintf(os.Stderr, "tls connecter error %T\n\t%s\n\t%v\n\t%#v\n\n", err, err, err, err)
 		return nil, err
 	}
 	tcpConn := conn.(*net.TCPConn)
diff --git a/transport/tls/serve_tls.go b/transport/tls/serve_tls.go
index dd156cc..0b28384 100644
--- a/transport/tls/serve_tls.go
+++ b/transport/tls/serve_tls.go
@@ -4,8 +4,10 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
+	"os"
 	"time"
 
+	"github.com/kr/pretty"
 	"github.com/pkg/errors"
 
 	"github.com/zrepl/zrepl/config"
@@ -68,6 +70,7 @@ type tlsAuthListener struct {
 func (l tlsAuthListener) Accept(ctx context.Context) (*transport.AuthConn, error) {
 	tcpConn, tlsConn, cn, err := l.ClientAuthListener.Accept()
 	if err != nil {
+		fmt.Fprintf(os.Stderr, "tlsAuthListener.Accept: l.ClientAuthListener.Accept returned error %T %s\n%s\n", err, err, pretty.Sprint(err))
 		return nil, err
 	}
 	if _, ok := l.clientCNs[cn]; !ok {