Clean up the logic for color logging

hoisie · hoisie · commit 22000d109c04 · 2016-08-06T10:50:47.000-07:00
Previously, the escape sequences for terminal colors were included
directly in the log string. This made it difficult to understand what
was being logged. Add some wrapper methods to clean up the abstraction
of the color output logic. Also, avoid using color logging if web.go
isn't running in a terminal (e.g the output is being piped).
diff --git a/server.go b/server.go
@@ -269,7 +269,6 @@ func (s *Server) tryServingFile(name string, req *http.Request, w http.ResponseW
 
 func (s *Server) logRequest(ctx Context, sTime time.Time) {
 	//log the request
-	var logEntry bytes.Buffer
 	req := ctx.Request
 	requestPath := req.URL.Path
 
@@ -285,22 +284,30 @@ func (s *Server) logRequest(ctx Context, sTime time.Time) {
 		client = req.RemoteAddr
 	}
 
-	if s.Config.ColorOutput {
-		fmt.Fprintf(&logEntry, "%s - \x1b[32;1m%s %s\x1b[0m - %v", client, req.Method, requestPath, duration)
-	} else {
-		fmt.Fprintf(&logEntry, "%s - %s %s - %v", client, req.Method, requestPath, duration)
-	}
-
+	var logEntry bytes.Buffer
+	logEntry.WriteString(client)
+	logEntry.WriteString(" - " + s.ttyGreen(req.Method+" "+requestPath))
+	logEntry.WriteString(" - " + duration.String())
 	if len(ctx.Params) > 0 {
-		if s.Config.ColorOutput {
-			fmt.Fprintf(&logEntry, " - \x1b[37;1mParams: %v\x1b[0m\n", ctx.Params)
-		} else {
-			fmt.Fprintf(&logEntry, " - Params: %v\n", ctx.Params)
-		}
+		logEntry.WriteString(" - " + s.ttyWhite(fmt.Sprintf("Params: %v\n", ctx.Params)))
 	}
-
 	ctx.Server.Logger.Print(logEntry.String())
+}
+
+func (s *Server) ttyGreen(msg string) string {
+	return s.ttyColor(msg, ttyCodes.green)
+}
+
+func (s *Server) ttyWhite(msg string) string {
+	return s.ttyColor(msg, ttyCodes.white)
+}
 
+func (s *Server) ttyColor(msg string, colorCode string) string {
+	if s.Config.ColorOutput {
+		return colorCode + msg + ttyCodes.reset
+	} else {
+		return msg
+	}
 }
 
 // the main route handler in web.go
diff --git a/ttycolors.go b/ttycolors.go
@@ -0,0 +1,30 @@
+package web
+
+import (
+	"golang.org/x/crypto/ssh/terminal"
+	"syscall"
+)
+
+var ttyCodes struct {
+	green string
+	white string
+	reset string
+}
+
+func init() {
+	ttyCodes.green = ttyBold("32")
+	ttyCodes.white = ttyBold("37")
+	ttyCodes.reset = ttyEscape("0")
+}
+
+func ttyBold(code string) string {
+	return ttyEscape("1;" + code)
+}
+
+func ttyEscape(code string) string {
+	if terminal.IsTerminal(syscall.Stdout) {
+		return "\x1b[" + code + "m"
+	} else {
+		return ""
+	}
+}
