Just warn on double-remove of a sub

piker/data/_sampling.py

@@ -15,7 +15,9 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 """
-Data buffers for fast shared humpy.
+Sampling and broadcast machinery for (soft) real-time delivery of
+financial data flows.
+
 """
 import time
 from typing import Dict, List
@@ -48,7 +50,8 @@ async def increment_ohlc_buffer(
     delay_s: int,
     task_status: TaskStatus[trio.CancelScope] = trio.TASK_STATUS_IGNORED,
 ):
-    """Task which inserts new bars into the provide shared memory array
+    '''
+    Task which inserts new bars into the provide shared memory array
     every ``delay_s`` seconds.
 
     This task fulfills 2 purposes:
@@ -59,8 +62,8 @@ async def increment_ohlc_buffer(
 
     Note that if **no** actor has initiated this task then **none** of
     the underlying buffers will actually be incremented.
-    """
 
+    '''
     # # wait for brokerd to signal we should start sampling
     # await shm_incrementing(shm_token['shm_name']).wait()
 
@@ -137,12 +140,12 @@ async def iter_ohlc_periods(
     delay_s: int,
 
 ) -> None:
-    """
+    '''
     Subscribe to OHLC sampling "step" events: when the time
     aggregation period increments, this event stream emits an index
     event.
 
-    """
+    '''
     # add our subscription
     global _subscribers
     subs = _subscribers.setdefault(delay_s, [])
@@ -290,7 +293,10 @@ async def sample_and_broadcast(
                     # so far seems like no since this should all
                     # be single-threaded. Doing it anyway though
                     # since there seems to be some kinda race..
+                    try:
                         subs.remove((stream, tick_throttle))
+                    except ValueError:
+                        log.error(f'{stream} was already removed from subs!?')
 
 
 # TODO: a less naive throttler, here's some snippets: