Fix newline escaping in line protocol (#3992)

plugins/serializers/influx/escape.go

@@ -3,30 +3,42 @@ package influx
 import "strings"
 
 const (
-	escapes            = " ,="
-	nameEscapes        = " ,"
-	stringFieldEscapes = `\"`
+	escapes            = "\t\n\f\r ,="
+	nameEscapes        = "\t\n\f\r ,"
+	stringFieldEscapes = "\t\n\f\r\\\""
 )
 
 var (
 	escaper = strings.NewReplacer(
+		"\t", `\t`,
+		"\n", `\n`,
+		"\f", `\f`,
+		"\r", `\r`,
 		`,`, `\,`,
-		`"`, `\"`, // ???
 		` `, `\ `,
 		`=`, `\=`,
 	)
 
 	nameEscaper = strings.NewReplacer(
+		"\t", `\t`,
+		"\n", `\n`,
+		"\f", `\f`,
+		"\r", `\r`,
 		`,`, `\,`,
 		` `, `\ `,
 	)
 
 	stringFieldEscaper = strings.NewReplacer(
+		"\t", `\t`,
+		"\n", `\n`,
+		"\f", `\f`,
+		"\r", `\r`,
 		`"`, `\"`,
 		`\`, `\\`,
 	)
 )
 
+// Escape a tagkey, tagvalue, or fieldkey
 func escape(s string) string {
 	if strings.ContainsAny(s, escapes) {
 		return escaper.Replace(s)
@@ -35,6 +47,7 @@ func escape(s string) string {
 	}
 }
 
+// Escape a measurement name
 func nameEscape(s string) string {
 	if strings.ContainsAny(s, nameEscapes) {
 		return nameEscaper.Replace(s)
@@ -43,6 +56,7 @@ func nameEscape(s string) string {
 	}
 }
 
+// Escape a string field
 func stringFieldEscape(s string) string {
 	if strings.ContainsAny(s, stringFieldEscapes) {
 		return stringFieldEscaper.Replace(s)