Implement String() method on events

To make it safe for logging safelog.Scrub function is now public.

Closes: #40141

client/pt_event_logger.go

@@ -1,12 +1,8 @@
 package main
 
 import (
-	"bytes"
-	"fmt"
 	pt "git.torproject.org/pluggable-transports/goptlib.git"
 	"git.torproject.org/pluggable-transports/snowflake.git/v2/common/event"
-	"git.torproject.org/pluggable-transports/snowflake.git/v2/common/safelog"
-	"strings"
 )
 
 func NewPTEventLogger() event.SnowflakeEventReceiver {
@@ -16,67 +12,6 @@ func NewPTEventLogger() event.SnowflakeEventReceiver {
 type ptEventLogger struct {
 }
 
-type logSeverity int
-
-const (
-	Debug logSeverity = iota
-	Info
-	Notice
-	Warning
-	Error
-)
-
-func safePTLog(severity logSeverity, format string, a ...interface{}) {
-	var buff bytes.Buffer
-	scrubber := &safelog.LogScrubber{Output: &buff}
-
-	// make sure logString ends with exactly one "\n" so it's not stuck in scrubber.Write()'s internal buffer
-	logString := strings.TrimRight(fmt.Sprintf(format, a...), "\n") + "\n"
-	scrubber.Write([]byte(logString))
-
-	// remove newline before calling pt.Log because it adds a newline
-	msg := strings.TrimRight(buff.String(), "\n")
-
-	switch severity {
-	case Error:
-		pt.Log(pt.LogSeverityError, msg)
-	case Warning:
-		pt.Log(pt.LogSeverityWarning, msg)
-	case Notice:
-		pt.Log(pt.LogSeverityWarning, msg)
-	case Info:
-		pt.Log(pt.LogSeverityInfo, msg)
-	case Debug:
-		pt.Log(pt.LogSeverityDebug, msg)
-	default:
-		pt.Log(pt.LogSeverityNotice, msg)
-	}
-}
-
 func (p ptEventLogger) OnNewSnowflakeEvent(e event.SnowflakeEvent) {
-	switch e.(type) {
-	case event.EventOnOfferCreated:
-		e := e.(event.EventOnOfferCreated)
-		if e.Error != nil {
-			safePTLog(Notice, "offer creation failure %v", e.Error.Error())
-		} else {
-			safePTLog(Notice, "offer created")
-		}
-
-	case event.EventOnBrokerRendezvous:
-		e := e.(event.EventOnBrokerRendezvous)
-		if e.Error != nil {
-			safePTLog(Notice, "broker failure %v", e.Error.Error())
-		} else {
-			safePTLog(Notice, "broker rendezvous peer received")
-		}
-
-	case event.EventOnSnowflakeConnected:
-		safePTLog(Notice, "connected")
-
-	case event.EventOnSnowflakeConnectionFailed:
-		e := e.(event.EventOnSnowflakeConnectionFailed)
-		safePTLog(Notice, "trying a new proxy: %v", e.Error.Error())
-	}
-
+	pt.Log(pt.LogSeverityNotice, e.String())
 }

common/event/interface.go

@@ -1,6 +1,11 @@
 package event
 
-import "github.com/pion/webrtc/v3"
+import (
+	"fmt"
+
+	"git.torproject.org/pluggable-transports/snowflake.git/v2/common/safelog"
+	"github.com/pion/webrtc/v3"
+)
 
 type SnowflakeEvent interface {
 	IsSnowflakeEvent()
@@ -13,27 +18,56 @@ type EventOnOfferCreated struct {
 	Error                  error
 }
 
+func (e EventOnOfferCreated) String() string {
+	if e.Error != nil {
+		scrubbed := safelog.Scrub([]byte(e.Error.Error()))
+		return fmt.Sprintf("offer creation failure %s", scrubbed)
+	}
+	return "offer created"
+}
+
 type EventOnBrokerRendezvous struct {
 	SnowflakeEvent
 	WebRTCRemoteDescription *webrtc.SessionDescription
 	Error                   error
 }
 
+func (e EventOnBrokerRendezvous) String() string {
+	if e.Error != nil {
+		scrubbed := safelog.Scrub([]byte(e.Error.Error()))
+		return fmt.Sprintf("broker failure %s", scrubbed)
+	}
+	return "broker rendezvous peer received"
+}
+
 type EventOnSnowflakeConnected struct {
 	SnowflakeEvent
 }
 
+func (e EventOnSnowflakeConnected) String() string {
+	return "connected"
+}
+
 type EventOnSnowflakeConnectionFailed struct {
 	SnowflakeEvent
 	Error error
 }
 
+func (e EventOnSnowflakeConnectionFailed) String() string {
+	scrubbed := safelog.Scrub([]byte(e.Error.Error()))
+	return fmt.Sprintf("trying a new proxy: %s", scrubbed)
+}
+
 type EventOnProxyConnectionOver struct {
 	SnowflakeEvent
 	InboundTraffic  int
 	OutboundTraffic int
 }
 
+func (e EventOnProxyConnectionOver) String() string {
+	return fmt.Sprintf("Proxy connection closed (↑ %d, ↓ %d)", e.InboundTraffic, e.OutboundTraffic)
+}
+
 type SnowflakeEventReceiver interface {
 	// OnNewSnowflakeEvent notify receiver about a new event
 	// This method MUST not block

common/safelog/log.go

@@ -38,7 +38,7 @@ type LogScrubber struct {
 func (ls *LogScrubber) Lock()   { (*ls).lock.Lock() }
 func (ls *LogScrubber) Unlock() { (*ls).lock.Unlock() }
 
-func scrub(b []byte) []byte {
+func Scrub(b []byte) []byte {
 	scrubbedBytes := b
 	for _, pattern := range scrubberPatterns {
 		// this is a workaround since go does not yet support look ahead or look
@@ -62,7 +62,7 @@ func (ls *LogScrubber) Write(b []byte) (n int, err error) {
 			return
 		}
 		fullLines := ls.buffer[:i+1]
-		_, err = ls.Output.Write(scrub(fullLines))
+		_, err = ls.Output.Write(Scrub(fullLines))
 		if err != nil {
 			return
 		}