[tail] format locally

JSON is actually unfit to send structured log messages, because
date/time is not well supported. So we are using BSON, which supports
those. BSON is, among the dozen serializers available, really a random
choice and might be changed in the future.

cmd/circolog-tail/main.go

@@ -11,7 +11,10 @@ import (
 	"strconv"
 	"time"
 
+	"git.lattuga.net/boyska/circolog/formatter"
 	"github.com/gorilla/websocket"
+	"gopkg.in/mcuadros/go-syslog.v2/format"
+	"gopkg.in/mgo.v2/bson"
 )
 
 func main() {
@@ -28,6 +31,7 @@ func main() {
 		Path: "/ws",
 	}
 	q := u.Query()
+	q.Set("fmt", "bson")
 	if *backlogLimit >= 0 {
 		q.Set("l", strconv.Itoa(*backlogLimit))
 	}
@@ -58,12 +62,20 @@ func main() {
 	go func() {
 		defer close(done)
 		for {
-			_, message, err := c.ReadMessage()
+			_, serialized, err := c.ReadMessage()
 			if err != nil {
 				log.Println("close:", err)
 				return
 			}
-			fmt.Println(string(message))
+			var parsed format.LogParts
+			if err := bson.Unmarshal(serialized, &parsed); err != nil {
+				log.Println("invalid YAML", err)
+				continue
+			}
+			if err := formatter.WriteFormatted(os.Stdout, formatter.FormatSyslog, parsed); err != nil {
+				log.Println("error printing", err)
+			}
+			fmt.Println()
 		}
 	}()
 

formatter/format.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"gopkg.in/mcuadros/go-syslog.v2/format"
+	"gopkg.in/mgo.v2/bson"
 )
 
 // Formatter is an interface, so that multiple implementations can exist
@@ -50,6 +51,8 @@ func (rf Format) String() string {
 		return "json"
 	case FormatSyslog:
 		return "syslog"
+	case FormatBSON:
+		return "bson"
 	}
 	return ""
 }
@@ -64,6 +67,8 @@ func parseFormat(s string) (Format, error) {
 		return FormatJSON, nil
 	case "syslog":
 		return FormatSyslog, nil
+	case "bson":
+		return FormatBSON, nil
 	default:
 		return 0, fmt.Errorf("Undefined format `%s`", s)
 	}
@@ -72,6 +77,7 @@ func parseFormat(s string) (Format, error) {
 const (
 	FormatSyslog = iota // 0
 	FormatJSON   = iota
+	FormatBSON   = iota
 )
 
 func WriteFormatted(w io.Writer, f Format, msg format.LogParts) error {
@@ -82,6 +88,13 @@ func WriteFormatted(w io.Writer, f Format, msg format.LogParts) error {
 		enc := json.NewEncoder(w)
 		enc.SetIndent("", "  ")
 		return enc.Encode(msg)
+	case FormatBSON:
+		enc, err := bson.Marshal(msg)
+		if err != nil {
+			return err
+		}
+		_, err = w.Write(enc)
+		return err
 	}
 	return nil
 }