circolog-tail has colors

cmd/circolog-tail/main.go

@@ -14,6 +14,8 @@ import (
 	"git.lattuga.net/boyska/circolog/filtering"
 	"git.lattuga.net/boyska/circolog/formatter"
 	"github.com/gorilla/websocket"
+	isatty "github.com/mattn/go-isatty"
+	"github.com/mgutz/ansi"
 	"gopkg.in/mcuadros/go-syslog.v2/format"
 	"gopkg.in/mgo.v2/bson"
 )
@@ -24,8 +26,21 @@ func main() {
 	backlogLimit := flag.Int("n", -1, "Limit the backlog length, defaults to no limit (-1)")
 	var filter filtering.ExprValue
 	flag.Var(&filter, "where", "sql-like query to filter logs")
+	// TODO: change to color-mode=auto/no/always
+	noColor := flag.Bool("no-color", false, "disable colors")
+	forceColor := flag.Bool("force-color", false, "force colors even on TTY")
 	flag.Parse()
 
+	if *noColor && *forceColor {
+		fmt.Fprintln(os.Stderr, "Can't use both -no-color and -force-color")
+		flag.Usage()
+		os.Exit(2)
+	}
+
+	if *noColor || (!isatty.IsTerminal(os.Stdout.Fd()) && !*forceColor) {
+		ansi.DisableColors(true)
+	}
+
 	interrupt := make(chan os.Signal, 1)
 	signal.Notify(interrupt, os.Interrupt)
 	var d *websocket.Dialer

formatter/format.go

@@ -7,6 +7,7 @@ import (
 	"text/template"
 	"time"
 
+	"github.com/mgutz/ansi"
 	"gopkg.in/mcuadros/go-syslog.v2/format"
 	"gopkg.in/mgo.v2/bson"
 )
@@ -27,17 +28,29 @@ func init() {
 		},
 		"sevName": func(s int) string {
 			names := []string{"emerg ", "alert ", "crit  ", "err   ", "warn  ", "notice", "info  ", "dbg   "}
-			if s >= len(names) {
+			switch {
+			case s < 2: // emerg..alert
+				return ansi.Color(names[s], "red+b")
+			case s < 4: // emerg..err
+				return ansi.Color(names[s], "red")
+			case s < 6: // warn..notice
+				return ansi.Color(names[s], "white+b")
+			case s >= len(names):
 				return "???"
-			}
+			default:
 				return names[s]
+			}
 		},
+		"color": func(color, text string) string {
+			return ansi.Color(text, color) // slow; should use colorfunc
+		},
+		"red": ansi.ColorFunc("red+b"),
 	}
 	syslogTmpl = template.Must(template.New("syslog").Funcs(tmplFuncs).Parse(
-		"{{rfc822 (index . \"timestamp\")}} {{index . \"hostname\"}} " +
+		"{{color \"yellow\" (rfc822 (index . \"timestamp\")) }} {{index . \"hostname\"}} " +
 			"{{index . \"app_name\"}}" +
 			"{{ if (ne (index . \"proc_id\") \"-\")}}[{{index . \"proc_id\"}}]{{end}}: " +
-			"<{{ sevName (index . \"severity\") }}> " +
+			"{{ sevName (index . \"severity\") }} " +
 			"{{index . \"message\"}}",
 	))
 }