Use pikerd to spawn emsd

piker/clearing/_client.py

@@ -168,26 +168,27 @@ async def send_order_cmds():
 
 @asynccontextmanager
 async def maybe_open_emsd(
-) -> 'StreamReceiveChannel':  # noqa
+    brokername: str,
+) -> tractor._portal.Portal:  # noqa
 
     async with tractor.find_actor('emsd') as portal:
         if portal is not None:
             yield portal
 
         else:
-            # we gotta spawn it
+            # ask remote daemon tree to spawn it
-            log.info("Spawning EMS daemon")
+            from .._daemon import spawn_emsd
 
-            # TODO: add ``maybe_spawn_emsd()`` for this
+            async with tractor.find_actor('pikerd') as portal:
-            async with tractor.open_nursery() as n:
 
-                portal = await n.start_actor(
+                if portal is not None:
-                    'emsd',
+
-                    enable_modules=[
+                    name = await portal.run(
-                        'piker.exchange._ems',
+                        spawn_emsd,
-                    ],
+                        brokername=brokername,
                     )
 
+                    async with tractor.wait_for_actor(name) as portal:
                         yield portal
 
 
@@ -235,7 +236,7 @@ async def open_ems(
     # ready for order commands
     book = get_orders()
 
-    async with maybe_open_emsd() as portal:
+    async with maybe_open_emsd(broker) as portal:
 
         trades_stream = await portal.run(
             _emsd_main,