Make option chain spawnable as a subactor

Look up the broker module and set up the loglevel locally.
Ask the arbiter for a portal to the data daemon since we can't
pass one to a subactor by reference.

piker/ui/option_chain.py

@@ -15,8 +15,9 @@ from kivy.app import async_runTouchApp
 from kivy.core.window import Window
 from kivy.uix.label import Label
 
-from ..log import get_logger
+from ..log import get_logger, get_console_log
 from ..brokers.data import DataFeed
+from ..brokers import get_brokermod
 from .pager import PagerView
 
 from .tabular import Row, HeaderCell, Cell, TickerTable
@@ -408,7 +409,7 @@ class OptionChain(object):
 
         self.render_rows(records, displayables)
 
-        with trio.open_cancel_scope() as cs:
+        with trio.CancelScope() as cs:
             self._update_cs = cs
             await self._nursery.start(
                 partial(
@@ -479,16 +480,24 @@ async def new_chain_ui(
 
 async def _async_main(
     symbol: str,
-    portal: tractor._portal.Portal,
-    brokermod: types.ModuleType,
+    brokername: str,
     rate: int = 1,
+    loglevel: str = 'info',
     test: bool = False
 ) -> None:
     '''Launch kivy app + all other related tasks.
 
     This is started with cli cmd `piker options`.
     '''
+    if loglevel is not None:
+        get_console_log(loglevel)
+
+    brokermod = get_brokermod(brokername)
+
     async with trio.open_nursery() as nursery:
+        # get a portal to the data feed daemon
+        async with tractor.wait_for_actor('brokerd') as portal:
+
             # set up a pager view for large ticker lists
             chain = await new_chain_ui(
                 portal,