fix: possible race condition sending wss packets

docs/release_notes.md

@@ -20,4 +20,4 @@
 
 ### 🐛 Fixed Issues
 
--
+- [Realtime] Fixed possible race condition in Realtime API implementation

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/realtime/WSOpenAiRealtimeClient.java

@@ -130,7 +130,7 @@ protected void sendMessage(@Nonnull final Object message) {
     }
     synchronized (this) {
       try {
-        ws.sendText(JACKSON.writeValueAsString(message), true);
+        ws.sendText(JACKSON.writeValueAsString(message), true).join();
         ws.request(1);
       } catch (final JsonProcessingException e) {
         throw new ClientException("Failed to serialize message", e);
@@ -165,6 +165,7 @@ protected synchronized void sendPing(@Nonnull final WebSocket ws) {
     if (ws.isInputClosed()) {
       return;
     }
+    log.trace("Sending wss ping");
     ws.sendPing(ByteBuffer.wrap("ping".getBytes(StandardCharsets.UTF_8))).join();
     ws.request(1);
   }

sample-code/spring-app/src/test/java/com/sap/ai/sdk/app/controllers/RealtimeApiTest.java

@@ -23,14 +23,16 @@ public class RealtimeApiTest {
 
   private static final double LOG_2 = Math.log(2.0);
 
-  private static byte[] HELLO_FIXTURE_PCM;
+  private static byte[] QUESTION_FIXTURE_PCM;
 
   private final OpenAiService service = new OpenAiService();
 
   @BeforeAll
   public static void setUp() {
-    try (var fis = new FileInputStream("src/test/resources/fixtures/hello.pcm")) {
-      HELLO_FIXTURE_PCM = fis.readAllBytes();
+    try (var fis =
+        new FileInputStream(
+            "src/test/resources/fixtures/what-is-the-german-word-for-chicken.pcm")) {
+      QUESTION_FIXTURE_PCM = fis.readAllBytes();
     } catch (IOException e) {
       fail(e.getMessage());
     }
@@ -90,7 +92,7 @@ void testSpeechToSpeech() {
             },
             RealtimeParamTurnDetection.EACH_CALL_IS_A_TURN,
             systemPrompt)) {
-      input.inputAudio(HELLO_FIXTURE_PCM);
+      input.inputAudio(QUESTION_FIXTURE_PCM);
       completed = monitor.await(55, TimeUnit.SECONDS);
     } catch (Exception e) {
       if (!(e instanceof InterruptedException)) {