print a warn message when the configuration file is not found

internal/conf/conf.go

@@ -145,45 +145,45 @@ func (conf *Conf) fillAndCheck() error {
 }
 
 // Load loads a Conf.
-func Load(fpath string) (*Conf, error) {
+func Load(fpath string) (*Conf, bool, error) {
 	conf := &Conf{}
 
 	// read from file
-	err := func() error {
+	found, err := func() (bool, error) {
 		// rtsp-simple-server.yml is optional
 		if fpath == "rtsp-simple-server.yml" {
 			if _, err := os.Stat(fpath); err != nil {
-				return nil
+				return false, nil
 			}
 		}
 
 		f, err := os.Open(fpath)
 		if err != nil {
-			return err
+			return false, err
 		}
 		defer f.Close()
 
 		err = yaml.NewDecoder(f).Decode(conf)
 		if err != nil {
-			return err
+			return false, err
 		}
 
-		return nil
+		return true, nil
 	}()
 	if err != nil {
-		return nil, err
+		return nil, false, err
 	}
 
 	// read from environment
 	err = confenv.Load("RTSP", conf)
 	if err != nil {
-		return nil, err
+		return nil, false, err
 	}
 
 	err = conf.fillAndCheck()
 	if err != nil {
-		return nil, err
+		return nil, false, err
 	}
 
-	return conf, nil
+	return conf, found, nil
 }

internal/confwatcher/confwatcher.go

@@ -1,7 +1,6 @@
 package confwatcher
 
 import (
-	"os"
 	"path/filepath"
 	"time"
 
@@ -29,16 +28,14 @@ func New(confPath string) (*ConfWatcher, error) {
 		return nil, err
 	}
 
-	if _, err := os.Stat(confPath); err == nil {
 	// use absolute path to support Darwin
 	absolutePath, _ := filepath.Abs(confPath)
 
-		err := inner.Add(absolutePath)
+	err = inner.Add(absolutePath)
 	if err != nil {
 		inner.Close()
 		return nil, err
 	}
-	}
 
 	w := &ConfWatcher{
 		inner:  inner,

main.go

@@ -27,6 +27,7 @@ var version = "v0.0.0"
 type program struct {
 	confPath      string
 	conf          *conf.Conf
+	confFound     bool
 	stats         *stats.Stats
 	logHandler    *loghandler.LogHandler
 	metrics       *metrics.Metrics
@@ -63,7 +64,7 @@ func newProgram(args []string) (*program, error) {
 	}
 
 	var err error
-	p.conf, err = conf.Load(p.confPath)
+	p.conf, p.confFound, err = conf.Load(p.confPath)
 	if err != nil {
 		return nil, err
 	}
@@ -74,11 +75,13 @@ func newProgram(args []string) (*program, error) {
 		return nil, err
 	}
 
+	if p.confFound {
 		p.confWatcher, err = confwatcher.New(p.confPath)
 		if err != nil {
 			p.closeAllResources()
 			return nil, err
 		}
+	}
 
 	go p.run()
 
@@ -102,10 +105,17 @@ func (p *program) Log(format string, args ...interface{}) {
 func (p *program) run() {
 	defer close(p.done)
 
+	confChanged := func() chan struct{} {
+		if p.confWatcher != nil {
+			return p.confWatcher.Watch()
+		}
+		return make(chan struct{})
+	}()
+
 outer:
 	for {
 		select {
-		case <-p.confWatcher.Watch():
+		case <-confChanged:
 			err := p.reloadConf()
 			if err != nil {
 				p.Log("ERR: %s", err)
@@ -136,6 +146,10 @@ func (p *program) createDynamicResources(initial bool) error {
 
 	if initial {
 		p.Log("rtsp-simple-server %s", version)
+
+		if !p.confFound {
+			p.Log("configuration file not found, using the default one")
+		}
 	}
 
 	if p.conf.Metrics {
@@ -239,7 +253,7 @@ func (p *program) closeAllResources() {
 func (p *program) reloadConf() error {
 	p.Log("reloading configuration")
 
-	conf, err := conf.Load(p.confPath)
+	conf, _, err := conf.Load(p.confPath)
 	if err != nil {
 		return err
 	}