add serializer

src/main.py

@@ -95,14 +95,17 @@ def detector_load(conf: dict, instrument: str) -> list[int]:
             active_detectors.append(k)
     return active_detectors
 
+def serializer(value):
+    return json.dumps(value).encode()
+
 async def fan_out_msg(
     producer,
     fan_out_topic,
     data
 ):
     await producer.start()
     logging.info(f"sending msg {data}")
-    await producer.send_and_wait(fan_out_topic, b(json.dumps(data)))
+    await producer.send_and_wait(fan_out_topic, data)
     await producer.stop()
 
 
@@ -369,7 +372,8 @@ async def main() -> None:
                     try:
                         # https://aiokafka.readthedocs.io/en/stable/producer.html
                         producer = AIOKafkaProducer(
-                            bootstrap_servers=prompt_processing_kafka_cluster
+                            bootstrap_servers=prompt_processing_kafka_cluster,
+                            value_serializer=serializer
                         )
                         await producer.start()
                         logging.info ("started kafka producer")