piker/piker/data/flows.py

211 lines
6.3 KiB
Python

# piker: trading gear for hackers
# Copyright (C) Tyler Goodlet (in stewardship for pikers)
# 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/>.
"""
abstractions for organizing, managing and generally operating-on
real-time data processing data-structures.
"Streams, flumes, cascades and flows.."
"""
from __future__ import annotations
from typing import (
TYPE_CHECKING,
)
import tractor
import pendulum
import numpy as np
from .types import Struct
from ._source import (
Symbol,
)
from ._sharedmem import (
attach_shm_array,
ShmArray,
_Token,
)
# from .._profile import (
# Profiler,
# pg_profile_enabled,
# )
if TYPE_CHECKING:
# from pyqtgraph import PlotItem
from .feed import Feed
# TODO: ideas for further abstractions as per
# https://github.com/pikers/piker/issues/216 and
# https://github.com/pikers/piker/issues/270:
# - a ``Cascade`` would be the minimal "connection" of 2 ``Flumes``
# as per circuit parlance:
# https://en.wikipedia.org/wiki/Two-port_network#Cascade_connection
# - could cover the combination of our `FspAdmin` and the
# backend `.fsp._engine` related machinery to "connect" one flume
# to another?
# - a (financial signal) ``Flow`` would be the a "collection" of such
# minmial cascades. Some engineering based jargon concepts:
# - https://en.wikipedia.org/wiki/Signal_chain
# - https://en.wikipedia.org/wiki/Daisy_chain_(electrical_engineering)
# - https://en.wikipedia.org/wiki/Audio_signal_flow
# - https://en.wikipedia.org/wiki/Digital_signal_processing#Implementation
# - https://en.wikipedia.org/wiki/Dataflow_programming
# - https://en.wikipedia.org/wiki/Signal_programming
# - https://en.wikipedia.org/wiki/Incremental_computing
class Flume(Struct):
'''
Composite reference type which points to all the addressing handles
and other meta-data necessary for the read, measure and management
of a set of real-time updated data flows.
Can be thought of as a "flow descriptor" or "flow frame" which
describes the high level properties of a set of data flows that can
be used seamlessly across process-memory boundaries.
Each instance's sub-components normally includes:
- a msg oriented quote stream provided via an IPC transport
- history and real-time shm buffers which are both real-time
updated and backfilled.
- associated startup indexing information related to both buffer
real-time-append and historical prepend addresses.
- low level APIs to read and measure the updated data and manage
queuing properties.
'''
symbol: Symbol
first_quote: dict
_rt_shm_token: _Token
# optional since some data flows won't have a "downsampled" history
# buffer/stream (eg. FSPs).
_hist_shm_token: _Token | None = None
# private shm refs loaded dynamically from tokens
_hist_shm: ShmArray | None = None
_rt_shm: ShmArray | None = None
stream: tractor.MsgStream | None = None
izero_hist: int = 0
izero_rt: int = 0
throttle_rate: int | None = None
# TODO: do we need this really if we can pull the `Portal` from
# ``tractor``'s internals?
feed: Feed | None = None
@property
def rt_shm(self) -> ShmArray:
if self._rt_shm is None:
self._rt_shm = attach_shm_array(
token=self._rt_shm_token,
readonly=True,
)
return self._rt_shm
@property
def hist_shm(self) -> ShmArray:
if self._hist_shm_token is None:
raise RuntimeError(
'No shm token has been set for the history buffer?'
)
if (
self._hist_shm is None
):
self._hist_shm = attach_shm_array(
token=self._hist_shm_token,
readonly=True,
)
return self._hist_shm
async def receive(self) -> dict:
return await self.stream.receive()
def get_ds_info(
self,
) -> tuple[float, float, float]:
'''
Compute the "downsampling" ratio info between the historical shm
buffer and the real-time (HFT) one.
Return a tuple of the fast sample period, historical sample
period and ratio between them.
'''
times = self.hist_shm.array['time']
end = pendulum.from_timestamp(times[-1])
start = pendulum.from_timestamp(times[times != times[-1]][-1])
hist_step_size_s = (end - start).seconds
times = self.rt_shm.array['time']
end = pendulum.from_timestamp(times[-1])
start = pendulum.from_timestamp(times[times != times[-1]][-1])
rt_step_size_s = (end - start).seconds
ratio = hist_step_size_s / rt_step_size_s
return (
rt_step_size_s,
hist_step_size_s,
ratio,
)
# TODO: get native msgspec decoding for these workinn
def to_msg(self) -> dict:
msg = self.to_dict()
msg['symbol'] = msg['symbol'].to_dict()
# can't serialize the stream or feed objects, it's expected
# you'll have a ref to it since this msg should be rxed on
# a stream on whatever far end IPC..
msg.pop('stream')
msg.pop('feed')
return msg
@classmethod
def from_msg(cls, msg: dict) -> dict:
symbol = Symbol(**msg.pop('symbol'))
return cls(
symbol=symbol,
**msg,
)
def get_index(
self,
time_s: float,
array: np.ndarray,
) -> int | float:
'''
Return array shm-buffer index for for epoch time.
'''
times = array['time']
first = np.searchsorted(
times,
time_s,
side='left',
)
imx = times.shape[0] - 1
return min(first, imx)