Don't try to parse hostname for RFC3164 over unix socket.

format/automatic.go

@@ -56,10 +56,10 @@ func detect(data []byte) (detected int, err error) {
 	return detectedUnknown, nil
 }
 
-func (f *Automatic) GetParser(line []byte) LogParser {
+func (f *Automatic) getAnyParser(line []byte, isUnixSocket bool) LogParser {
 	switch format, _ := detect(line); format {
 	case detectedRFC3164:
-		return &parserWrapper{rfc3164.NewParser(line)}
+		return &parserWrapper{rfc3164.NewParser(line, isUnixSocket)}
 	case detectedRFC5424:
 		return &parserWrapper{rfc5424.NewParser(line)}
 	default:
@@ -69,10 +69,18 @@ func (f *Automatic) GetParser(line []byte) LogParser {
 		// will return detectedRFC6587. The line may also simply be malformed after the length in
 		// which case we will have detectedUnknown. In this case we return the simplest parser so
 		// the illegally formatted line is properly handled
-		return &parserWrapper{rfc3164.NewParser(line)}
+		return &parserWrapper{rfc3164.NewParser(line, isUnixSocket)}
 	}
 }
 
+func (f *Automatic) GetParser(line []byte) LogParser {
+	return f.getAnyParser(line, false)
+}
+
+func (f *Automatic) GetParserUnixSocket(line []byte) LogParser {
+	return f.getAnyParser(line, true)
+}
+
 func (f *Automatic) GetSplitFunc() bufio.SplitFunc {
 	return f.automaticScannerSplit
 }

format/format.go

@@ -17,6 +17,7 @@ type LogParser interface {
 
 type Format interface {
 	GetParser([]byte) LogParser
+	GetParserUnixSocket([]byte) LogParser
 	GetSplitFunc() bufio.SplitFunc
 }
 

format/rfc3164.go

@@ -9,7 +9,11 @@ import (
 type RFC3164 struct{}
 
 func (f *RFC3164) GetParser(line []byte) LogParser {
-	return &parserWrapper{rfc3164.NewParser(line)}
+	return &parserWrapper{rfc3164.NewParser(line, false)}
+}
+
+func (f *RFC3164) GetParserUnixSocket(line []byte) LogParser {
+	return &parserWrapper{rfc3164.NewParser(line, true)}
 }
 
 func (f *RFC3164) GetSplitFunc() bufio.SplitFunc {

format/rfc5424.go

@@ -12,6 +12,10 @@ func (f *RFC5424) GetParser(line []byte) LogParser {
 	return &parserWrapper{rfc5424.NewParser(line)}
 }
 
+func (f *RFC5424) GetParserUnixSocket(line []byte) LogParser {
+	return f.GetParser(line)
+}
+
 func (f *RFC5424) GetSplitFunc() bufio.SplitFunc {
 	return nil
 }

format/rfc6587.go

@@ -14,6 +14,10 @@ func (f *RFC6587) GetParser(line []byte) LogParser {
 	return &parserWrapper{rfc5424.NewParser(line)}
 }
 
+func (f *RFC6587) GetParserUnixSocket(line []byte) LogParser {
+	return f.GetParser(line)
+}
+
 func (f *RFC6587) GetSplitFunc() bufio.SplitFunc {
 	return rfc6587ScannerSplit
 }

internal/syslogparser/rfc3164/rfc3164.go

@@ -8,15 +8,16 @@ import (
 )
 
 type Parser struct {
-	buff     []byte
-	cursor   int
-	l        int
-	priority syslogparser.Priority
-	version  int
-	header   header
-	message  rfc3164message
-	location *time.Location
-	skipTag  bool
+	buff         []byte
+	cursor       int
+	l            int
+	priority     syslogparser.Priority
+	version      int
+	header       header
+	message      rfc3164message
+	location     *time.Location
+	skipTag      bool
+	skipHostname bool
 }
 
 type header struct {
@@ -29,12 +30,13 @@ type rfc3164message struct {
 	content string
 }
 
-func NewParser(buff []byte) *Parser {
+func NewParser(buff []byte, skipHostname bool) *Parser {
 	return &Parser{
-		buff:     buff,
-		cursor:   0,
-		l:        len(buff),
-		location: time.UTC,
+		buff:         buff,
+		cursor:       0,
+		l:            len(buff),
+		location:     time.UTC,
+		skipHostname: skipHostname,
 	}
 }
 
@@ -186,6 +188,9 @@ func (p *Parser) parseTimestamp() (time.Time, error) {
 }
 
 func (p *Parser) parseHostname() (string, error) {
+	if p.skipHostname {
+		return "", nil
+	}
 	return syslogparser.ParseHostname(p.buff, &p.cursor, p.l)
 }
 

server.go

@@ -250,7 +250,14 @@ loop:
 }
 
 func (s *Server) parser(line []byte, client string, tlsPeer string) {
-	parser := s.format.GetParser(line)
+	var parser format.LogParser
+
+	if client == "" {
+		parser = s.format.GetParserUnixSocket(line)
+	} else {
+		parser = s.format.GetParser(line)
+	}
+
 	err := parser.Parse()
 	if err != nil {
 		s.lastError = err