Try out `@trio_util.async_generator` for streaming

Apparently it will likely fix our `trio`-cancel-scopes-corrupted crash
when we try to let our `._web_bs.NoBsWs` do reconnect logic around
the asyn-generator implemented data-feed streaming routines in `binance`
and `kraken`.  See the project docs for deatz; obvs we add the lib as
a dep.

piker/brokers/binance.py

@@ -26,7 +26,7 @@ from typing import (
 )
 import time
 
-from async_generator import aclosing
+from trio_util import trio_async_generator
 import trio
 from trio_typing import TaskStatus
 import pendulum
@@ -318,7 +318,10 @@ class AggTrade(Struct):
     M: bool  # Ignore
 
 
-async def stream_messages(ws: NoBsWs) -> AsyncGenerator[NoBsWs, dict]:
+@trio_async_generator
+async def stream_messages(
+    ws: NoBsWs,
+) -> AsyncGenerator[NoBsWs, dict]:
 
     timeouts = 0
     while True:
@@ -540,7 +543,7 @@ async def stream_quotes(
             ) as ws,
 
             # avoid stream-gen closure from breaking trio..
-            aclosing(stream_messages(ws)) as msg_gen,
+            stream_messages(ws) as msg_gen,
         ):
             typ, quote = await anext(msg_gen)
 

piker/brokers/kraken/feed.py

@@ -27,11 +27,11 @@ from typing import (
 )
 import time
 
-from async_generator import aclosing
 from fuzzywuzzy import process as fuzzy
 import numpy as np
 import pendulum
 from trio_typing import TaskStatus
+from trio_util import trio_async_generator
 import tractor
 import trio
 
@@ -122,6 +122,7 @@ async def stream_messages(
                 yield msg
 
 
+@trio_async_generator
 async def process_data_feed_msgs(
     ws: NoBsWs,
 ):
@@ -378,7 +379,12 @@ async def stream_quotes(
                 'wss://ws.kraken.com/',
                 fixture=subscribe,
             ) as ws,
-            aclosing(process_data_feed_msgs(ws)) as msg_gen,
+
+            # avoid stream-gen closure from breaking trio..
+            # NOTE: not sure this actually works XD particularly
+            # if we call `ws._connect()` manally in the streaming
+            # async gen..
+            process_data_feed_msgs(ws) as msg_gen,
         ):
             # pull a first quote and deliver
             typ, ohlc_last = await anext(msg_gen)

setup.py

@@ -53,6 +53,7 @@ setup(
         # async
         'trio',
         'trio-websocket',
+        'trio-util',
         'async_generator',
 
         # from github currently (see requirements.txt)