X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=adapter%2Fvppapiclient%2Fvppapiclient_adapter.go;h=e9948e8f2bc3b4daef8f6682aa86cfd520ab31e7;hb=392a56b700fa6715d091e56c49f79bfe32613fc6;hp=82c820e3818ab59ea49ecd3542c0522a7f509844;hpb=96c3dce9de1aded53c1e4bf098817fc59692eb64;p=govpp.git

diff --git a/adapter/vppapiclient/vppapiclient_adapter.go b/adapter/vppapiclient/vppapiclient_adapter.go
index 82c820e..e9948e8 100644
--- a/adapter/vppapiclient/vppapiclient_adapter.go
+++ b/adapter/vppapiclient/vppapiclient_adapter.go
@@ -77,12 +77,22 @@ govpp_get_msg_index(char *name_and_crc)
 import "C"
 
 import (
-	"errors"
 	"fmt"
+	"os"
 	"reflect"
 	"unsafe"
 
-	"gerrit.fd.io/r/govpp.git/adapter"
+	"git.fd.io/govpp.git/adapter"
+	"github.com/fsnotify/fsnotify"
+)
+
+const (
+	// watchedFolder is a folder where vpp's shared memory is supposed to be created.
+	// File system events are monitored in this folder.
+	watchedFolder = "/dev/shm/"
+	// watchedFile is a name of the file in the watchedFolder. Once the file is present
+	// the vpp is ready to accept a new connection.
+	watchedFile = watchedFolder + "vpe-api"
 )
 
 // vppAPIClientAdapter is the opaque context of the adapter.
@@ -114,12 +124,12 @@ func (a *vppAPIClientAdapter) Disconnect() {
 
 // GetMsgID returns a runtime message ID for the given message name and CRC.
 func (a *vppAPIClientAdapter) GetMsgID(msgName string, msgCrc string) (uint16, error) {
-	nameAndCrc := C.CString(fmt.Sprintf("%s_%s", msgName, msgCrc))
+	nameAndCrc := C.CString(msgName + "_" + msgCrc)
 	defer C.free(unsafe.Pointer(nameAndCrc))
 
 	msgID := uint16(C.govpp_get_msg_index(nameAndCrc))
 	if msgID == ^uint16(0) {
-		return msgID, errors.New("unkonwn message")
+		return msgID, fmt.Errorf("unknown message: %v (crc: %v)", msgName, msgCrc)
 	}
 
 	return msgID, nil
@@ -139,6 +149,42 @@ func (a *vppAPIClientAdapter) SetMsgCallback(cb func(context uint32, msgID uint1
 	a.callback = cb
 }
 
+// WaitReady blocks until shared memory for sending
+// binary api calls is present on the file system.
+func (a *vppAPIClientAdapter) WaitReady() error {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		return err
+	}
+	defer watcher.Close()
+
+	err = watcher.Add(watchedFolder)
+	if err != nil {
+		return err
+	}
+
+	if fileExists(watchedFile) {
+		return nil
+	}
+
+	for {
+		ev := <-watcher.Events
+		if ev.Name == watchedFile && (ev.Op&fsnotify.Create) == fsnotify.Create {
+			break
+		}
+	}
+	return nil
+}
+
+func fileExists(name string) bool {
+	if _, err := os.Stat(name); err != nil {
+		if os.IsNotExist(err) {
+			return false
+		}
+	}
+	return true
+}
+
 //export go_msg_callback
 func go_msg_callback(msgID C.uint16_t, context C.uint32_t, data unsafe.Pointer, size C.size_t) {
 	// convert unsafe.Pointer to byte slice