add flags for color control (from log's 1.6.0) (#8)

README.md

@@ -31,31 +31,42 @@ func main() {
 	cli.Main() // Will have either called cli.ExitFunction or everything is valid
 	// Next line output won't show when passed -quiet
 	log.Infof("Info test, -myflag is %q", *myFlag)
+	// This always shows
 	log.Printf("Hello world, version %s, args %v", cli.ShortVersion, flag.Args())
+	// This shows and is colorized and structured, unless loglevel is set to critical.
+	log.S(log.Error, "Error test",
+		log.Str("myflag", *myFlag),
+		log.Attr("num_args", len(flag.Args())),
+		log.Attr("args", flag.Args()))
 }
 ```
 
 ```bash
 $ sampleTool a
-sampleTool 1.0.0 usage:
+sampleTool 1.2.0 usage:
 	sampleTool [flags] arg1 arg2 [arg3...arg4]
 or 1 of the special arguments
 	sampleTool {help|version|buildinfo}
 flags:
+  -logger-force-color
+    	Force color output even if stderr isn't a terminal
+  -logger-no-color
+    	Prevent colorized output even if stderr is a terminal
   -loglevel level
     	log level, one of [Debug Verbose Info Warning Error Critical Fatal] (default Info)
   -myflag string
     	my flag (default "default")
   -quiet
-    	Quiet mode, sets log level to warning
+    	Quiet mode, sets loglevel to Error (quietly) to reduces the output
 At least 2 arguments expected, got 1
 ```
 
-or normal case
+or normal case (and now in color when on console)
 ```bash
 $ sampleTool a b
-15:42:17 I Info test, -myflag is "default"
-15:42:17 Hello world, version dev, args [a b]
+15:30:50.217 I Info test, -myflag is "default"
+15:30:50.217 I Hello world, version dev, args [a b]
+15:30:50.217 E Error test, myflag="default", num_args="2", args="[a b]"
 ```
 
 ## Additional builtins
@@ -94,6 +105,10 @@ or 1 of the special arguments
 	multicurl {help|version|buildinfo}
 flags:
 [...]
+  -logger-force-color
+    	Force color output even if stderr isn't a terminal
+  -logger-no-color
+    	Prevent colorized output even if stderr is a terminal
   -loglevel level
     	log level, one of [Debug Verbose Info Warning Error Critical Fatal] (default Info)
   -quiet

cli.go

@@ -78,6 +78,10 @@ func usage(w io.Writer, msg string, args ...any) {
 func Main() {
 	quietFlag := flag.Bool("quiet", false,
 		"Quiet mode, sets loglevel to Error (quietly) to reduces the output")
+	flag.BoolVar(&log.Config.ForceColor, "logger-force-color", false,
+		"Force color output even if stderr isn't a terminal")
+	nocolor := flag.Bool("logger-no-color", false,
+		"Prevent colorized output even if stderr is a terminal")
 	ShortVersion, LongVersion, FullVersion = version.FromBuildInfo()
 	log.Config.FatalExit = ExitFunction
 	baseExe = filepath.Base(os.Args[0])
@@ -132,6 +136,8 @@ func Main() {
 		os.Args = append([]string{os.Args[0]}, os.Args[2:]...)
 	}
 	flag.Parse()
+	log.Config.ConsoleColor = !*nocolor
+	log.SetColorMode()
 	nArgs = len(flag.Args())
 	argsRange := (MinArgs != MaxArgs)
 	exactly := "Exactly"

go.mod

@@ -3,6 +3,6 @@ module fortio.org/cli
 go 1.18
 
 require (
-	fortio.org/log v1.2.2
+	fortio.org/log v1.6.0
 	fortio.org/version v1.0.2
 )

go.sum

@@ -1,4 +1,4 @@
-fortio.org/log v1.2.2 h1:vs42JjNwiqbMbacittZjJE9+oi72Za6aekML9gKmILg=
-fortio.org/log v1.2.2/go.mod h1:u/8/2lyczXq52aT5Nw6reD+3cR6m/EbS2jBiIYhgiTU=
+fortio.org/log v1.6.0 h1:GYt2UjoZdURBEb7J1fxBmLOirOrKvKhKKi7xLScqg1A=
+fortio.org/log v1.6.0/go.mod h1:u/8/2lyczXq52aT5Nw6reD+3cR6m/EbS2jBiIYhgiTU=
 fortio.org/version v1.0.2 h1:8NwxdX58aoeKx7T5xAPO0xlUu1Hpk42nRz5s6e6eKZ0=
 fortio.org/version v1.0.2/go.mod h1:2JQp9Ax+tm6QKiGuzR5nJY63kFeANcgrZ0osoQFDVm0=

sampleTool/main.go

@@ -14,5 +14,11 @@ func main() {
 	cli.Main() // Will have either called cli.ExitFunction or everything is valid
 	// Next line output won't show when passed -quiet
 	log.Infof("Info test, -myflag is %q", *myFlag)
+	// This always shows
 	log.Printf("Hello world, version %s, args %v", cli.ShortVersion, flag.Args())
+	// This shows and is colorized and structured, unless loglevel is set to critical.
+	log.S(log.Error, "Error test",
+		log.Str("myflag", *myFlag),
+		log.Attr("num_args", len(flag.Args())),
+		log.Attr("args", flag.Args()))
 }