piker/piker/data/_buffer.py

117 lines
3.8 KiB
Python

# piker: trading gear for hackers
# Copyright (C) 2018-present Tyler Goodlet (in stewardship of piker0)
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
"""
Data buffers for fast shared humpy.
"""
from typing import Tuple, Callable, Dict
# import time
import tractor
import trio
from ._sharedmem import ShmArray
_shms: Dict[int, ShmArray] = {}
@tractor.msg.pub
async def increment_ohlc_buffer(
shm_token: dict,
get_topics: Callable[..., Tuple[str]],
# delay_s: Optional[float] = None,
):
"""Task which inserts new bars into the provide shared memory array
every ``delay_s`` seconds.
This task fulfills 2 purposes:
- it takes the subscribed set of shm arrays and increments them
on a common time period
- broadcast of this increment "signal" message to other actor
subscribers
Note that if **no** actor has initiated this task then **none** of
the underlying buffers will actually be incremented.
"""
# TODO: right now we'll spin printing bars if the last time stamp is
# before a large period of no market activity. Likely the best way
# to solve this is to make this task aware of the instrument's
# tradable hours?
# adjust delay to compensate for trio processing time
ad = min(_shms.keys()) - 0.001
# async def sleep():
# """Sleep until next time frames worth has passed from last bar.
# """
# # last_ts = shm.array[-1]['time']
# # delay = max((last_ts + ad) - time.time(), 0)
# # await trio.sleep(delay)
# await trio.sleep(ad)
total_s = 0 # total seconds counted
lowest = min(_shms.keys())
ad = lowest - 0.001
while True:
# TODO: do we want to support dynamically
# adding a "lower" lowest increment period?
await trio.sleep(ad)
total_s += lowest
# # sleep for duration of current bar
# await sleep()
# increment all subscribed shm arrays
# TODO: this in ``numba``
for delay_s, shms in _shms.items():
if total_s % delay_s != 0:
continue
# TODO: numa this!
for shm in shms:
# TODO: in theory we could make this faster by copying the
# "last" readable value into the underlying larger buffer's
# next value and then incrementing the counter instead of
# using ``.push()``?
# append new entry to buffer thus "incrementing" the bar
array = shm.array
last = array[-1:][shm._write_fields].copy()
# (index, t, close) = last[0][['index', 'time', 'close']]
(t, close) = last[0][['time', 'close']]
# this copies non-std fields (eg. vwap) from the last datum
last[
['time', 'volume', 'open', 'high', 'low', 'close']
][0] = (t + delay_s, 0, close, close, close, close)
# write to the buffer
shm.push(last)
# broadcast the buffer index step
yield {'index': shm._last.value}
def subscribe_ohlc_for_increment(
shm: ShmArray,
delay: int,
) -> None:
"""Add an OHLC ``ShmArray`` to the increment set.
"""
_shms.setdefault(delay, []).append(shm)