Allow debug level logs at startup.

Added a -debug flag which causes the logger in main to start with debug
level logs.

cmd/micromdm/micromdm.go

@@ -31,6 +31,7 @@ func writePID(path string) error {
 }
 
 type cliFlags struct {
+	debug    bool
 	siteName string
 	http     string
 	pidfile  string
@@ -38,14 +39,15 @@ type cliFlags struct {
 
 func micromdm(args []string, stdin io.Reader, stdout, stderr io.Writer) int {
 	var (
+		logger log.Logger
 		ctx    = context.Background()
-		logger = log.New(log.Output(stderr))
 		cli    = &cliFlags{}
 		rootfs = flag.NewFlagSet("micromdm", flag.ContinueOnError)
 		_      = rootfs.String("config", "", "Path to config file (optional)")
 	)
 
 	rootfs.StringVar(&cli.pidfile, "pidfile", "/tmp/micromdm.pid", "Path to server pidfile")
+	rootfs.BoolVar(&cli.debug, "debug", false, "Allow debug level")
 	rootfs.StringVar(&cli.siteName, "site_name", "Acme", "Name of the site as it would appear in the top left of the HTML UI")
 	rootfs.StringVar(&cli.http, "http", "localhost:9000", "HTTP service address")
 
@@ -80,6 +82,14 @@ func micromdm(args []string, stdin io.Reader, stdout, stderr io.Writer) int {
 		Options:     []ff.Option{ff.WithEnvVarPrefix("MICROMDM"), ff.WithConfigFileParser(ff.PlainParser), ff.WithConfigFileFlag("config")},
 		Subcommands: []*ffcli.Command{helpCmd, version},
 		Exec: func(context.Context, []string) error {
+
+			logOpts := []log.Option{log.Output(stderr)}
+			if cli.debug {
+				logOpts = append(logOpts, log.StartDebug())
+			}
+
+			logger = log.New(logOpts...)
+
 			if err := writePID(cli.pidfile); err != nil {
 				return err
 			}

cmd/micromdm/micromdm_test.go

@@ -44,7 +44,7 @@ func checkExitAfterSignal(t *testing.T, stdin, stdout, stderr *bytes.Buffer) {
 
 func checkLogSwap(t *testing.T, stdin, stdout, stderr *bytes.Buffer) {
 	output := stderr.String()
-	debugsub := `level=debug msg="swapping level" debug=true`
+	debugsub := `level=info msg="swapping level" debug=true`
 	if !strings.Contains(output, debugsub) {
 		t.Errorf("want %q in output, got:\n%s", debugsub, output)
 	}

pkg/log/logger.go

@@ -67,6 +67,13 @@ func JSON() Option {
 	}
 }
 
+// StartDebug creates a logger configured to allow debug level logs from the start.
+func StartDebug() Option {
+	return func(c *config) {
+		c.debug = true
+	}
+}
+
 // Output configures the log output. Stderr is default.
 func Output(w io.Writer) Option {
 	return func(c *config) {
@@ -78,6 +85,7 @@ type config struct {
 	w      io.Writer
 	format func(io.Writer) log.Logger
 	sig    os.Signal
+	debug  bool
 }
 
 // New creates a Logger.
@@ -96,11 +104,14 @@ func New(opts ...Option) *log.SwapLogger {
 	base = log.With(base, "ts", log.DefaultTimestampUTC)
 	base = level.NewInjector(base, level.InfoValue())
 	lev := level.AllowInfo()
+	if c.debug {
+		lev = level.AllowDebug()
+	}
 
 	var swapLogger log.SwapLogger
 	swapLogger.Swap(level.NewFilter(base, lev))
 
-	go c.swapLevelHandler(base, &swapLogger, false)
+	go c.swapLevelHandler(base, &swapLogger, c.debug)
 	return &swapLogger
 }
 
@@ -116,7 +127,7 @@ func (c *config) swapLevelHandler(base Logger, swapLogger *log.SwapLogger, debug
 			newLogger := level.NewFilter(base, level.AllowDebug())
 			swapLogger.Swap(newLogger)
 		}
-		Debug(swapLogger).Log("msg", "swapping level", "debug", !debug)
+		Info(swapLogger).Log("msg", "swapping level", "debug", !debug)
 		debug = !debug
 	}
 }