Allow wl app to spawn a broker daemon in a subprocess

piker/cli.py

@@ -1,20 +1,23 @@
 """
 Console interface to broker client/daemons.
 """
+from collections import defaultdict
 from functools import partial
 from importlib import import_module
-import os
-from collections import defaultdict
+from multiprocessing import Process
 import json
+import os
+import signal
+import time
 
 import click
-import trio
 import pandas as pd
+import trio
 
-
-from .log import get_console_log, colorize_json, get_logger
 from . import watchlists as wl
 from .brokers import core, get_brokermod
+from .brokers.core import _daemon_main
+from .log import get_console_log, colorize_json, get_logger
 
 log = get_logger('cli')
 DEFAULT_BROKER = 'robinhood'
@@ -36,15 +39,11 @@ def run(main, loglevel='info'):
 
 
 @click.command()
-@click.option('--broker', '-b', default=DEFAULT_BROKER,
-              help='Broker backend to use')
 @click.option('--loglevel', '-l', default='warning', help='Logging level')
-def pikerd(broker, loglevel):
+def pikerd(loglevel):
     """Spawn the piker daemon.
     """
-    from piker.brokers.core import _daemon_main
-    brokermod = get_brokermod(broker)
-    run(partial(_daemon_main, brokermod), loglevel)
+    run(_daemon_main, loglevel)
 
 
 @click.group()
@@ -134,7 +133,53 @@ def watch(loglevel, broker, rate, name):
     brokermod = get_brokermod(broker)
     watchlist_from_file = wl.ensure_watchlists(_watchlists_data_path)
     watchlists = wl.merge_watchlist(watchlist_from_file, wl._builtins)
-    trio.run(_async_main, name, watchlists[name], brokermod, rate)
+    tickers = watchlists[name]
+
+    # setup ticker stream
+    from .brokers.core import Client
+
+    async def main(timeout=1):
+        async def subscribe(client):
+            # initial request for symbols price streams
+            await client.send((brokermod.name, tickers))
+
+        client = Client(('127.0.0.1', 1616), subscribe)
+        start = time.time()
+        while True:
+            try:
+                await client.connect()
+                break
+            except OSError as oserr:
+                log.info("Waiting on daemon to come up...")
+                await trio.sleep(0.1)
+                if time.time() - start > timeout:
+                    raise
+                continue
+
+        async with trio.open_nursery() as nursery:
+            nursery.start_soon(
+                _async_main, name, client, tickers,
+                brokermod, rate
+            )
+
+    try:
+        trio.run(main)
+    except OSError as oserr:
+        log.exception(oserr)
+        answer = input(
+            "\nWould you like to spawn a broker daemon locally? [Y/n]")
+        if answer is not 'n':
+            child = Process(
+                target=run,
+                args=(_daemon_main, loglevel),
+                daemon=True,
+            )
+            child.daemon = True
+            child.start()
+            trio.run(main, 5)
+            # trio dies with a keyboard interrupt
+            os.kill(child.pid, signal.SIGINT)
+            child.join()
 
 
 @cli.group()

piker/ui/watchlist.py

@@ -382,20 +382,11 @@ async def run_kivy(root, nursery):
     nursery.cancel_scope.cancel()  # cancel all other tasks that may be running
 
 
-async def _async_main(name, tickers, brokermod, rate):
+async def _async_main(name, client, tickers, brokermod, rate):
     '''Launch kivy app + all other related tasks.
 
     This is started with cli command `piker watch`.
     '''
-    # setup ticker stream
-    from ..brokers.core import Client
-
-    async def subscribe(client):
-        # initial request for symbols price streams
-        await client.send((brokermod.name, tickers))
-
-    async with Client(('127.0.0.1', 1616), subscribe) as client:
-
     # get initial symbol data
     async with brokermod.get_client() as bclient:
         # get long term data including last days close price