Merge pull request #1141 from skrashevich/feat-log-terminal-check

feat(logging): add interactive shell detection for console output

internal/app/app.go

@@ -119,7 +119,7 @@ func Init() {
 	}
 
 	cfg.Mod = map[string]string{
-		"format": "color",
+		"format": "", // useless, but anyway
 		"level":  "info",
 		"output": "stdout", // TODO: change to stderr someday
 		"time":   zerolog.TimeFormatUnixMs,

internal/app/log.go

@@ -4,16 +4,21 @@ import (
 	"io"
 	"os"
 
+	"github.com/mattn/go-isatty"
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
 )
 
 var MemoryLog = newBuffer(16)
 
+// NewLogger support:
+// - output: empty (only to memory), stderr, stdout
+// - format: empty (autodetect color support), color, json, text
+// - time:   empty (disable timestamp), UNIXMS, UNIXMICRO, UNIXNANO
+// - level:  disabled, trace, debug, info, warn, error...
 func NewLogger(config map[string]string) zerolog.Logger {
 	var writer io.Writer
 
-	// support output only to memory
 	switch config["output"] {
 	case "stderr":
 		writer = os.Stderr
@@ -24,26 +29,31 @@ func NewLogger(config map[string]string) zerolog.Logger {
 	timeFormat := config["time"]
 
 	if writer != nil {
-		switch format := config["format"]; format {
-		case "color", "text":
+		if format := config["format"]; format != "json" {
+			console := &zerolog.ConsoleWriter{Out: writer}
+
+			switch format {
+			case "text":
+				console.NoColor = true
+			case "color":
+				console.NoColor = false // useless, but anyway
+			default:
+				// autodetection if output support color
+				// go-isatty - dependency for go-colorable - dependency for ConsoleWriter
+				console.NoColor = !isatty.IsTerminal(writer.(*os.File).Fd())
+			}
+
 			if timeFormat != "" {
-				writer = &zerolog.ConsoleWriter{
-					Out:        writer,
-					NoColor:    format == "text",
-					TimeFormat: "15:04:05.000",
-				}
+				console.TimeFormat = "15:04:05.000"
 			} else {
-				writer = &zerolog.ConsoleWriter{
-					Out:     writer,
-					NoColor: format == "text",
-					PartsOrder: []string{
-						zerolog.LevelFieldName,
-						zerolog.CallerFieldName,
-						zerolog.MessageFieldName,
-					},
+				console.PartsOrder = []string{
+					zerolog.LevelFieldName,
+					zerolog.CallerFieldName,
+					zerolog.MessageFieldName,
 				}
 			}
-		case "json": // none
+
+			writer = console
 		}
 
 		writer = zerolog.MultiLevelWriter(writer, MemoryLog)