Add quote polling; pseudo-streaming

Add a ``poll_tickers`` coro which can be used to "stream" quotes at
a requested rate. Expose through a cli subcommand `piker stream`.
Drop the `pikerd` command for now.

piker/brokers/cli.py

@@ -1,7 +1,6 @@
 """
 Console interface to broker client/daemons.
 """
-import json
 from functools import partial
 from importlib import import_module
 
@@ -23,15 +22,6 @@ def run(main, loglevel='info'):
         log.debug("Exiting piker")
 
 
-@click.command()
-@click.option('--broker', default='questrade', help='Broker backend to use')
-@click.option('--loglevel', '-l', default='info', help='Logging level')
-def pikerd(broker, loglevel):
-    # import broker module daemon entry point
-    brokermod = import_module('.' + broker, 'piker.brokers')
-    run(brokermod.serve_forever, loglevel)
-
-
 @click.group()
 def cli():
     pass
@@ -59,3 +49,18 @@ def api(meth, kwargs, loglevel, broker):
     data = run(partial(brokermod.api, meth, **_kwargs), loglevel=loglevel)
     if data:
         click.echo(colorize_json(data))
+
+
+@cli.command()
+@click.option('--broker', default='questrade', help='Broker backend to use')
+@click.option('--loglevel', '-l', default='info', help='Logging level')
+@click.argument('tickers', nargs=-1)
+def stream(broker, loglevel, tickers):
+    # import broker module daemon entry point
+    bm = import_module('.' + broker, 'piker.brokers')
+    run(
+        partial(bm.serve_forever, [
+            partial(bm.poll_tickers, tickers=tickers)
+        ]),
+        loglevel
+    )

piker/brokers/questrade.py

@@ -140,6 +140,17 @@ class Client:
         self._prep_sess()
         return self.access_data
 
+    async def tickers2ids(self, tickers):
+        """Helper routine that take a sequence of ticker symbols and returns
+        their corresponding QT symbol ids.
+        """
+        data = await self.api.symbols(names=','.join(tickers))
+        symbols2ids = {}
+        for ticker, symbol in zip(tickers, data['symbols']):
+            symbols2ids[symbol['symbol']] = symbol['symbolId']
+
+        return symbols2ids
+
 
 class API:
     """Questrade API at its finest.
@@ -234,15 +245,34 @@ async def get_client() -> Client:
         write_conf(client)
 
 
-async def serve_forever() -> None:
+async def serve_forever(tasks) -> None:
     """Start up a client and serve until terminated.
     """
     async with get_client() as client:
         # pretty sure this doesn't work
         # await client._revoke_auth_token()
+
         async with trio.open_nursery() as nursery:
+            # launch token manager
             nursery.start_soon(token_refresher, client)
 
+            # launch children
+            for task in tasks:
+                nursery.start_soon(task, client)
+
+
+async def poll_tickers(client, tickers, rate=2):
+    """Auto-poll snap quotes for a sequence of tickers at the given ``rate``
+    per second.
+    """
+    t2ids = await client.tickers2ids(tickers)
+    sleeptime = 1. / rate
+    ids = ','.join(map(str, t2ids.values()))
+
+    while True:  # use an event here to trigger exit?
+        quote_data = await client.api.quotes(ids=ids)
+        await trio.sleep(sleeptime)
+
 
 async def api(methname, **kwargs) -> dict:
     """Make (proxy) through an api call by name and return its result.

setup.py

@@ -28,7 +28,6 @@ setup(
     ],
     entry_points={
         'console_scripts': [
-            'pikerd = piker.brokers.cli:pikerd',
             'piker = piker.brokers.cli:cli',
         ]
     },