L2SS-1906: Periodically publish all metadata

tangostationcontrol/tangostationcontrol/devices/metadata.py

@@ -14,7 +14,11 @@ from tango.server import device_property, attribute, command
 
 # PyTango imports
 from lofar_station_client.common import CaseInsensitiveDict
-from tangostationcontrol.common.constants import DEFAULT_POLLING_PERIOD_METADATA_MS
+from tangostationcontrol.common.asyncio import PeriodicTask
+from tangostationcontrol.common.constants import (
+    DEFAULT_POLLING_PERIOD_METADATA_MS,
+    DEFAULT_POLLING_PERIOD_MS,
+)
 from tangostationcontrol.common.device_decorators import only_in_states
 from tangostationcontrol.common.lofar_logging import log_exceptions
 from tangostationcontrol.common.states import DEFAULT_COMMAND_STATES
@@ -47,39 +51,60 @@ class Metadata(LOFARDevice):
 
     metadata_topic = device_property(dtype="DevString", default_value="metadata")
 
+    metadata_periodic_publish_interval = device_property(
+        dtype="DevFloat",
+        doc="Interval with which to force publication of all metadata.",
+        mandatory=False,
+        default_value=600.0,
+    )
+
     # ----------
     # Attributes
     # ----------
 
+    @attribute(
+        doc="Whether the metadata is periodically published",
+        dtype=bool,
+        # Tango needs to poll this, as otherwise this attribute will never
+        # be exposed as "False" as the event thread must run to do so.
+        polling_period=DEFAULT_POLLING_PERIOD_MS,
+    )
+    def metadata_periodic_publish_thread_running_R(self):
+        return (
+            self.event_loop_thread
+            and self.event_loop_thread.is_running()
+            and self.metadata_periodic_publish_task
+            and self.metadata_periodic_publish_task.is_running()
+        )
+
     @attribute(
         doc="Is the metadata publisher running",
         dtype=bool,
     )
-    def is_running_R(self):
-        if self._publisher:
-            return self._publisher.is_running
-        return False
+    def is_publisher_running_R(self):
+        return self._publisher.is_running if self._publisher else False
 
     @attribute(
         doc="Is the metadata publisher stopping",
         dtype=bool,
     )
-    def is_stopping_R(self):
-        if self._publisher:
-            return self._publisher.is_stopping
-        return False
+    def is_publisher_stopping_R(self):
+        return self._publisher.is_stopping if self._publisher else False
 
     @attribute(
-        doc="Queue fill percentage",
+        doc="Fraction of queue filled between metadata organizer and metadata publisher",
         dtype=numpy.float64,
     )
-    def queue_fill_percentage_R(self):
-        if self._publisher:
-            return self._publisher.queue_fill / self._publisher.queue_size
-        return 0.0
+    def publisher_queue_fill_fraction_R(self):
+        return (
+            self._publisher.queue_fill / self._publisher.queue_size
+            if self._publisher
+            else 0.0
+        )
 
     @attribute(
-        doc="Number of messages published since device was started", dtype=numpy.int64
+        doc="Number of messages sent to the publisher since device was started",
+        dtype=numpy.int64,
     )
     def messages_published_R(self):
         return self._num_published
@@ -139,6 +164,7 @@ class Metadata(LOFARDevice):
         self._num_published = 0
         self._publisher = None
         self._organizer = None
+        self.metadata_periodic_publish_task = None
 
         # Super must be called after variable assignment due to executing init_device!
         super().__init__(cl, name)
@@ -186,9 +212,20 @@ class Metadata(LOFARDevice):
         if not self._organizer:
             self._organizer = MetadataOrganizer(config=self.METADATA_CONFIG)
 
+    @log_exceptions()
+    def configure_for_on(self):
+        """Initialises the attributes and properties of the statistics device."""
+        super().configure_for_on()
+
         proxies = self._organizer.create_proxies()
         self.register_change_event_subscriptions(proxies)
 
+        self.metadata_periodic_publish_task = PeriodicTask(
+            self.event_loop_thread.event_loop,
+            self._send_metadata_async,
+            self.metadata_periodic_publish_interval,
+        )
+
     def register_change_event_subscriptions(self, proxies: metadata_proxy_type):
         """Register change events for working device proxies"""
 
@@ -243,6 +280,10 @@ class Metadata(LOFARDevice):
         self._publisher.send(self._organizer.get_json())
         self._num_published += 1
 
+    async def _send_metadata_async(self):
+        """"""
+        self._send_metadata()
+
     @command()
     @DebugIt()
     @only_in_states(DEFAULT_COMMAND_STATES)