Fix WaitReady if directory does not exist (#84)

* Fix WaitReady if directory does not exist

Signed-off-by: Ondrej Fabry <ofabry@cisco.com>

* Watch directories recursively in WaitReady

Signed-off-by: Ondrej Fabry <ofabry@cisco.com>

Signed-off-by: Ondrej Fabry <ofabry@cisco.com>

adapter/socketclient/socketclient.go

@@ -20,6 +20,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"net"
 	"os"
 	"path/filepath"
@@ -49,7 +50,7 @@ var (
 	// DefaultDisconnectTimeout is default timeout for discconnecting
 	DefaultDisconnectTimeout = time.Millisecond * 100
 	// MaxWaitReady defines maximum duration of waiting for socket file
-	MaxWaitReady = time.Second * 10
+	MaxWaitReady = time.Second * 3
 )
 
 var (
@@ -132,20 +133,37 @@ func (c *Client) SetDisconnectTimeout(t time.Duration) {
 	c.disconnectTimeout = t
 }
 
+// SetMsgCallback sets the callback for incoming messages.
 func (c *Client) SetMsgCallback(cb adapter.MsgCallback) {
 	log.Debug("SetMsgCallback")
 	c.msgCallback = cb
 }
 
-// WaitReady checks socket file existence and waits for it if necessary
+// WaitReady checks if the socket file exists and if it does not exist waits for
+// it for the duration defined by MaxWaitReady.
 func (c *Client) WaitReady() error {
+	socketDir, _ := filepath.Split(c.socketPath)
+	dirChain := strings.Split(filepath.ToSlash(filepath.Clean(socketDir)), "/")
+
+	dir := "/"
+	for _, dirElem := range dirChain {
+		dir = filepath.Join(dir, dirElem)
+		if err := waitForDir(dir); err != nil {
+			return err
+		}
+		log.Debugf("dir ready: %v", dir)
+	}
+
 	// check if socket already exists
 	if _, err := os.Stat(c.socketPath); err == nil {
 		return nil // socket exists, we are ready
-	} else if !os.IsNotExist(err) {
+	} else if !errors.Is(err, fs.ErrNotExist) {
+		log.Debugf("error is: %+v", err)
 		return err // some other error occurred
 	}
 
+	log.Debugf("waiting for file: %v", c.socketPath)
+
 	// socket does not exist, watch for it
 	watcher, err := fsnotify.NewWatcher()
 	if err != nil {
@@ -158,17 +176,21 @@ func (c *Client) WaitReady() error {
 	}()
 
 	// start directory watcher
-	if err := watcher.Add(filepath.Dir(c.socketPath)); err != nil {
+	d := filepath.Dir(c.socketPath)
+	if err := watcher.Add(d); err != nil {
+		log.Debugf("watcher add(%v) error: %v", d, err)
 		return err
 	}
 
 	timeout := time.NewTimer(MaxWaitReady)
 	for {
 		select {
 		case <-timeout.C:
+			log.Debugf("watcher timeout after: %v", MaxWaitReady)
 			return fmt.Errorf("timeout waiting (%s) for socket file: %s", MaxWaitReady, c.socketPath)
 
 		case e := <-watcher.Errors:
+			log.Debugf("watcher error: %+v", e)
 			return e
 
 		case ev := <-watcher.Events:
@@ -181,6 +203,56 @@ func (c *Client) WaitReady() error {
 	}
 }
 
+func waitForDir(dir string) error {
+	// check if dir already exists
+	if _, err := os.Stat(dir); err == nil {
+		return nil // dir exists, we are ready
+	} else if !errors.Is(err, fs.ErrNotExist) {
+		log.Debugf("error is: %+v", err)
+		return err // some other error occurred
+	}
+
+	log.Debugf("waiting for dir: %v", dir)
+
+	// dir does not exist, watch for it
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err := watcher.Close(); err != nil {
+			log.Debugf("failed to close file watcher: %v", err)
+		}
+	}()
+
+	// start watching directory
+	d := filepath.Dir(dir)
+	if err := watcher.Add(d); err != nil {
+		log.Debugf("watcher add (%v) error: %v", d, err)
+		return err
+	}
+
+	timeout := time.NewTimer(MaxWaitReady)
+	for {
+		select {
+		case <-timeout.C:
+			log.Debugf("watcher timeout after: %v", MaxWaitReady)
+			return fmt.Errorf("timeout waiting (%s) for directory: %s", MaxWaitReady, dir)
+
+		case e := <-watcher.Errors:
+			log.Debugf("watcher error: %+v", e)
+			return e
+
+		case ev := <-watcher.Events:
+			log.Debugf("watcher event: %+v", ev)
+			if ev.Name == dir && (ev.Op&fsnotify.Create) == fsnotify.Create {
+				// socket created, we are ready
+				return nil
+			}
+		}
+	}
+}
+
 func (c *Client) Connect() error {
 	// check if socket exists
 	if _, err := os.Stat(c.socketPath); os.IsNotExist(err) {
@@ -465,7 +537,7 @@ func (c *Client) readerLoop() {
 
 // getMsgReplyHeader gets message ID and context from the message reply header
 //
-// Message reply has following structure:
+// Message reply has the following structure:
 //
 //	type msgReplyHeader struct {
 //	    MsgID       uint16