Don't short circuit relay loop when headless

If no clients are connected we now process as normal and try to fire
a desktop notification on linux.

piker/clearing/_ems.py

@@ -44,8 +44,8 @@ from ..data.feed import (
     Feed,
     maybe_open_feed,
 )
+from ..ui._notify import notify_from_ems_status_msg
 from ..data.types import Struct
-# from .._daemon import maybe_spawn_brokerd
 from . import _paper_engine as paper
 from ._messages import (
     Order,
@@ -557,7 +557,7 @@ class Router(Struct):
         sub_key: str,
         msg: dict,
 
-    ) -> None:
+    ) -> bool:
         to_remove: set[tractor.MsgStream] = set()
 
         if sub_key == 'all':
@@ -567,9 +567,11 @@ class Router(Struct):
         else:
             subs = self.subscribers[sub_key]
 
+        sent_some: bool = False
         for client_stream in subs:
             try:
                 await client_stream.send(msg)
+                sent_some = True
             except (
                 trio.ClosedResourceError,
                 trio.BrokenResourceError,
@@ -582,6 +584,8 @@ class Router(Struct):
         if to_remove:
             subs.difference_update(to_remove)
 
+        return sent_some
+
 
 _router: Router = None
 
@@ -760,13 +764,8 @@ async def translate_and_relay_brokerd_events(
                 # TODO: maybe pack this into a composite type that
                 # contains both the IPC stream as well the
                 # msg-chain/dialog.
-                ems_client_order_streams = router.get_subs(oid)
                 status_msg = book._active.get(oid)
-
-                if (
-                    not ems_client_order_streams
-                    or not status_msg
-                ):
+                if not status_msg:
                     log.warning(
                         f'Received status for untracked dialog {oid}:\n'
                         f'{fmsg}'
@@ -788,10 +787,20 @@ async def translate_and_relay_brokerd_events(
                 status_msg.brokerd_msg = msg
                 status_msg.src = msg.broker_details['name']
 
-                await router.client_broadcast(
+                sent_some = await router.client_broadcast(
                     status_msg.req.symbol,
                     status_msg,
                 )
+                if not sent_some:
+                    log.info(
+                        'No clients attached, firing notification for msg:\n'
+                        f'{fmsg}'
+                    )
+                    await notify_from_ems_status_msg(
+                        oid,
+                        status_msg,
+                        is_subproc=True,
+                    )
 
                 if status == 'closed':
                     log.info(f'Execution for {oid} is complete!')