Move brokerd spawner to `brokers.core`

piker/brokers/core.py

@@ -5,16 +5,25 @@ import inspect
 from types import ModuleType
 from typing import List, Dict, Any, Optional
 
+from async_generator import asynccontextmanager
+import tractor
+
 from ..log import get_logger
 from .data import DataFeed
+from . import get_brokermod
 
 
 log = get_logger('broker.core')
+_data_mods = [
+    'piker.brokers.core',
+    'piker.brokers.data',
+]
 
 
-async def api(brokermod: ModuleType, methname: str, **kwargs) -> dict:
+async def api(brokername: str, methname: str, **kwargs) -> dict:
     """Make (proxy through) a broker API call by name and return its result.
     """
+    brokermod = get_brokermod(brokername)
     async with brokermod.get_client() as client:
 
         meth = getattr(client.api, methname, None)
@@ -39,6 +48,24 @@ async def api(brokermod: ModuleType, methname: str, **kwargs) -> dict:
         return await meth(**kwargs)
 
 
+@asynccontextmanager
+async def maybe_spawn_brokerd_as_subactor(sleep=0.5, tries=10, loglevel=None):
+    """If no ``brokerd`` daemon-actor can be found spawn one in a
+    local subactor.
+    """
+    async with tractor.open_nursery() as nursery:
+        async with tractor.find_actor('brokerd') as portal:
+            if not portal:
+                log.info(
+                    "No broker daemon could be found, spawning brokerd..")
+                portal = await nursery.start_actor(
+                    'brokerd',
+                    rpc_module_paths=_data_mods,
+                    loglevel=loglevel,
+                )
+            yield portal
+
+
 async def stocks_quote(
     brokermod: ModuleType,
     tickers: List[str]