Refactor log-fmt as flag.Value. Move in formatter pkg.

cmd/circologd/main.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"git.lattuga.net/boyska/circolog"
+	"git.lattuga.net/boyska/circolog/formatter"
 	"github.com/coreos/go-systemd/daemon"
 	syslog "gopkg.in/mcuadros/go-syslog.v2"
 )
@@ -22,22 +23,10 @@ func cleanSocket(socket string) {
 	}
 }
 
-func setSyslogFormat(server *syslog.Server, format string) {
-	switch {
-	case format == "auto":
-		server.SetFormat(syslog.Automatic)
-	case format == "rfc3164":
-		server.SetFormat(syslog.RFC3164)
-	case format == "rfc5424":
-		server.SetFormat(syslog.RFC5424)
-	}
-	// TODO: propose a patch to mcuadros/go-syslog.v2
-	// to get the format from the server itself.
-	log.Printf("Syslog format set to: %s\n", format)
-}
-
 func main() {
 	var err error
+	var logFmt formatter.SyslogRFC
+	logFmt = formatter.Auto
 	syslogSocketPath := flag.String("syslogd-socket", "", "The socket to listen to syslog addresses")
 	// dumpSocketPath := flag.String("dump-socket", "/run/buffer.sock", "The socket that user will connect to in order to receive logs")
 	bufsize := flag.Int("buffer-size", 1000, "Number of messages to keep")
@@ -45,7 +34,7 @@ func main() {
 	queryAddr := flag.String("query-addr", "127.0.0.1:9080", "Address:port where to bind the query service")
 	querySocket := flag.String("query-socket", "", "Path to a unix domain socket for the HTTP server; recommended for security reasons!")
 	ctlSocket := flag.String("ctl-socket", "/tmp/circologd-ctl.sock", "Path to a unix domain socket for the control server; leave empty to disable")
-	logFmt := flag.String("log-fmt", "auto", "Log messages format. If not set, defaults to automatic choice. Allowed values: rfc3164, rfc5424.")
+	flag.Var(&logFmt, "log-fmt", "Log messages format. If not set, defaults to automatic choice. Allowed values: rfc3164, rfc5424, auto.")
 	verbose := flag.Bool("verbose", false, "Print more output executing the daemon")
 	debug := flag.Bool("debug", false, "Print debugging info executing the daemon")
 	flag.Parse()
@@ -58,7 +47,7 @@ func main() {
 	go hub.Run()
 
 	server := syslog.NewServer()
-	setSyslogFormat(server, *logFmt)
+	formatter.SetSyslogFormat(server, logFmt)
 	server.SetHandler(handler)
 	if *syslogSocketPath != "" {
 		if err = server.ListenUnixgram(*syslogSocketPath); err != nil {

formatter/rfc.go

@@ -0,0 +1,67 @@
+package formatter
+
+import (
+	"errors"
+	"log"
+
+	syslog "gopkg.in/mcuadros/go-syslog.v2"
+)
+
+type SyslogRFC string
+
+// SetSyslogFormat does the job of setting the server parser to the provided RFC log format.
+func SetSyslogFormat(server *syslog.Server, format SyslogRFC) {
+	switch {
+	case format == Auto:
+		server.SetFormat(syslog.Automatic)
+	case format == RFC3164:
+		server.SetFormat(syslog.RFC3164)
+	case format == RFC5424:
+		server.SetFormat(syslog.RFC5424)
+	}
+	log.Printf("Syslog format set to: %s\n", format)
+}
+
+func (rfc *SyslogRFC) Set(v string) error {
+	newval, err := parseRFCValue(v)
+	if err != nil {
+		return err
+	}
+	*rfc = newval
+	return nil
+}
+
+func (rfc *SyslogRFC) String() string {
+	switch {
+	case *rfc == Auto:
+		return "auto"
+	case *rfc == RFC3164:
+		return "rfc3164"
+	case *rfc == RFC5424:
+		return "rfc5424"
+	}
+	return ""
+}
+
+func parseRFCValue(v string) (SyslogRFC, error) {
+	switch {
+	case v == "rfc3164":
+		return RFC3164, nil
+	case v == "rfc5424":
+		return RFC5424, nil
+	case v == "auto":
+		return Auto, nil
+	default:
+		return "", ErrRFCNotSupported
+	}
+}
+
+const (
+	RFC3164 = "rfc3164"
+	RFC5424 = "rfc5424"
+	Auto    = "auto"
+)
+
+// ErrRFCNotSupported is raised if the supplied rfc string is
+// not recognized.
+var ErrRFCNotSupported = errors.New("RFC not known")