socketclient: wait for socket to be created

[govpp.git] / adapter / socketclient / socketclient.go

diff --git a/adapter/socketclient/socketclient.go b/adapter/socketclient/socketclient.go
index eec4fd0..f281955 100644 (file)
--- a/adapter/socketclient/socketclient.go
+++ b/adapter/socketclient/socketclient.go
@@ -4,9 +4,11 @@ import (
        "bufio"
        "bytes"
        "fmt"
+       "github.com/fsnotify/fsnotify"
        "io"
        "net"
        "os"
+       "path/filepath"
        "strings"
        "sync"
        "time"
@@ -72,9 +74,39 @@ func nilCallback(msgID uint16, data []byte) {
        Log.Warnf("no callback set, dropping message: ID=%v len=%d", msgID, len(data))
 }
 
-func (*vppClient) WaitReady() error {
-       // TODO: add watcher for socket file?
-       return nil
+// WaitReady checks socket file existence and waits for it if necessary
+func (c *vppClient) WaitReady() error {
+       // verify file existence
+       if _, err := os.Stat(c.sockAddr); err == nil {
+               return nil
+       } else if os.IsExist(err) {
+               return err
+       }
+
+       // if not, watch for it
+       watcher, err := fsnotify.NewWatcher()
+       if err != nil {
+               return err
+       }
+       defer func() {
+               if err := watcher.Close(); err != nil {
+                       Log.Errorf("failed to close file watcher: %v", err)
+               }
+       }()
+       path := filepath.Dir(c.sockAddr)
+       if err := watcher.Add(path); err != nil {
+               return err
+       }
+
+       for {
+               ev := <-watcher.Events
+               if ev.Name == path {
+                       if (ev.Op & fsnotify.Create) == fsnotify.Create {
+                               // socket ready
+                               return nil
+                       }
+               }
+       }
 }
 
 func (c *vppClient) SetMsgCallback(cb adapter.MsgCallback) {