Feat: Add data to metadata stream.

src/AsapoWorker/asapo_receiver.py

@@ -325,10 +325,17 @@ class AsapoMetadataReceiver:
             raise StreamError("Failed to get substream list") from err
 
     def get_substream_metadata(self, substream):
+        """
+        Return the last available entry from given substream
+        of the metadata stream
+
+        Parameters
+        ----------
+        substream : str
+            Name of substream
+        """
         try:
-            data, metadata = self.broker.get_by_id(
-                1, self.group_id, substream=substream)
-            return metadata
+            return self.broker.get_last(self.group_id, substream=substream)
         except asapo_consumer.AsapoEndOfStreamError as err:
             raise EndOfStreamError("End of metadata stream") from err
         except (asapo_consumer.AsapoUnavailableServiceError,

src/AsapoWorker/streamer.py

@@ -65,10 +65,10 @@ class Streamer:
             log.info(format_error(err))
             # The substream might have been skipped
             self._handle_end_of_stream()
-            return None
+            return None, None
         except TemporaryError as err:
             log.warn(format_error(err))
-            return None
+            return None, None
 
     def _get_next(self):
         try:
@@ -164,7 +164,7 @@ class Streamer:
             if self.metadata_receiver:
                 log.info("Waiting for substream metadata")
                 while not self.stopped.is_set():
-                    substream_metadata = self._get_substream_metadata()
+                    data, substream_metadata = self._get_substream_metadata()
                     if substream_metadata:
                         self._reset_delay_on_error()
                         break
@@ -176,7 +176,7 @@ class Streamer:
                     return
 
                 log.info("Performing pre-scan setup")
-                self.worker.pre_scan(substream_metadata["meta"])
+                self.worker.pre_scan(data, substream_metadata)
 
             log.info("Start stream processing.")
             while not self.stopped.is_set():

src/AsapoWorker/worker.py

@@ -26,6 +26,20 @@ class Worker:
     def handle_receiver_critical_error(self):
         self.handle_receiver_error()
 
+    def pre_scan(self, data, metadata):
+        """
+        If metadata stream is given this function is called at the beginning of
+        each stream before get_next is called.
+
+        Parameters
+        ----------
+        data:
+            data of the metadata stream
+        metadata: dict
+            metadata of the metadata steam
+        """
+        pass
+
     def send(self, data, metadata):
         if self.sender:
             self.sender.send_data(data, metadata)