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Begin formalizing `Sampler` singleton API 

We're moving toward a single actor managing sampler work and distributed
independently of `brokerd` services such that a user can run samplers on
different hosts then real-time data feed infra. Most of the
implementation details include aggregating `.data._sampling` routines
into a new `Sampler` singleton type.

Move the following methods to class methods:
- `.increment_ohlc_buffer()` to allow a single task to increment all
  registered shm buffers.
- `.broadcast()` for IPC relay to all registered clients/shms.

Further add a new `maybe_open_global_sampler()` which allocates
a service nursery and assigns it to the `Sampler.service_nursery`; this
is prep for putting the step incrementer in a singleton service task
higher up the data-layer actor tree.
samplerd_service
Tyler Goodlet 2023-01-03 11:54:18 -05:00
parent b5f2ff854c
commit 2c76cee928
2 changed files with 174 additions and 143 deletions
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76
piker/data/_sampling.py
View File

@ -33,7 +33,10 @@ import tractor
import trio
from trio_typing import TaskStatus
from ..log import get_logger
from ..log import (
get_logger,
get_console_log,
)
if TYPE_CHECKING:
from ._sharedmem import ShmArray
@ -45,7 +48,7 @@ log = get_logger(__name__)
_default_delay_s: float = 1.0
class sampler:
class Sampler:
'''
Global sampling engine registry.
@ -53,6 +56,8 @@ class sampler:
sample period logic.
'''
service_nursery: None | trio.Nursery = None
# TODO: we could stick these in a composed type to avoid
# angering the "i hate module scoped variables crowd" (yawn).
ohlcv_shms: dict[int, list[ShmArray]] = {}
@ -67,8 +72,9 @@ class sampler:
# notified on a step.
subscribers: dict[int, tractor.Context] = {}
@classmethod
async def increment_ohlc_buffer(
self,
delay_s: int,
task_status: TaskStatus[trio.CancelScope] = trio.TASK_STATUS_IGNORED,
):
@ -95,17 +101,17 @@ async def increment_ohlc_buffer(
# tradable hours?
# adjust delay to compensate for trio processing time
ad = min(sampler.ohlcv_shms.keys()) - 0.001
ad = min(self.ohlcv_shms.keys()) - 0.001
total_s = 0 # total seconds counted
lowest = min(sampler.ohlcv_shms.keys())
lowest_shm = sampler.ohlcv_shms[lowest][0]
lowest = min(self.ohlcv_shms.keys())
lowest_shm = self.ohlcv_shms[lowest][0]
ad = lowest - 0.001
with trio.CancelScope() as cs:
# register this time period step as active
sampler.incrementers[delay_s] = cs
self.incrementers[delay_s] = cs
task_status.started(cs)
while True:
@ -118,7 +124,7 @@ async def increment_ohlc_buffer(
# TODO:
# - this in ``numba``
# - just lookup shms for this step instead of iterating?
for this_delay_s, shms in sampler.ohlcv_shms.items():
for this_delay_s, shms in self.ohlcv_shms.items():
# short-circuit on any not-ready because slower sample
# rate consuming shm buffers.
@ -128,7 +134,8 @@ async def increment_ohlc_buffer(
# TODO: ``numba`` this!
for shm in shms:
# append new entry to buffer thus "incrementing" the bar
# append new entry to buffer thus "incrementing"
# the bar
array = shm.array
last = array[-1:][shm._write_fields].copy()
@ -145,7 +152,8 @@ async def increment_ohlc_buffer(
# print(f'epoch {shm.token["shm_name"]}: {next_t}')
# this copies non-std fields (eg. vwap) from the last datum
# this copies non-std fields (eg. vwap) from the
# last datum
last[[
'time',
@ -168,18 +176,20 @@ async def increment_ohlc_buffer(
0, # vlm
)
# 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()``?
# 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()``?
# write to the buffer
shm.push(last)
await broadcast(delay_s, shm=lowest_shm)
await self.broadcast(delay_s, shm=lowest_shm)
@classmethod
async def broadcast(
self,
delay_s: int,
shm: ShmArray | None = None,
@ -192,17 +202,17 @@ async def broadcast(
the buffer's non-empty data.
'''
subs = sampler.subscribers.get(delay_s, ())
subs = self.subscribers.get(delay_s, ())
first = last = -1
if shm is None:
periods = sampler.ohlcv_shms.keys()
periods = self.ohlcv_shms.keys()
# if this is an update triggered by a history update there
# might not actually be any sampling bus setup since there's
# no "live feed" active yet.
if periods:
lowest = min(periods)
shm = sampler.ohlcv_shms[lowest][0]
shm = self.ohlcv_shms[lowest][0]
first = shm._first.value
last = shm._last.value
@ -227,6 +237,32 @@ async def broadcast(
f'{stream._ctx.chan.uid} sub already removed!?'
)
@classmethod
async def broadcast_all(self) -> None:
for delay_s in self.subscribers:
await self.broadcast(delay_s)
@tractor.context
async def maybe_open_global_sampler(
ctx: tractor.Context,
brokername: str,
) -> None:
get_console_log(tractor.current_actor().loglevel)
global Sampler
async with trio.open_nursery() as service_nursery:
Sampler.service_nursery = service_nursery
# unblock caller
await ctx.started()
# we pin this task to keep the feeds manager active until the
# parent actor decides to tear it down
await trio.sleep_forever()
@tractor.context
async def iter_ohlc_periods(
@ -241,7 +277,7 @@ async def iter_ohlc_periods(
'''
# add our subscription
subs = sampler.subscribers.setdefault(delay_s, [])
subs = Sampler.subscribers.setdefault(delay_s, [])
await ctx.started()
async with ctx.open_stream() as stream:
subs.append(stream)

21
piker/data/feed.py
View File

@ -74,9 +74,7 @@ from ._source import (
)
from ..ui import _search
from ._sampling import (
sampler,
broadcast,
increment_ohlc_buffer,
Sampler,
sample_and_broadcast,
uniform_rate_send,
_default_delay_s,
@ -327,8 +325,7 @@ async def start_backfill(
# TODO: *** THIS IS A BUG ***
# we need to only broadcast to subscribers for this fqsn..
# otherwise all fsps get reset on every chart..
for delay_s in sampler.subscribers:
await broadcast(delay_s)
await Sampler.broadcast_all()
# signal that backfilling to tsdb's end datum is complete
bf_done = trio.Event()
@ -496,8 +493,7 @@ async def start_backfill(
# in the block above to avoid entering new ``frames``
# values while we're pipelining the current ones to
# memory...
for delay_s in sampler.subscribers:
await broadcast(delay_s)
await Sampler.broadcast_all()
# short-circuit (for now)
bf_done.set()
@ -738,8 +734,7 @@ async def tsdb_backfill(
# (usually a chart showing graphics for said fsp)
# which tells the chart to conduct a manual full
# graphics loop cycle.
for delay_s in sampler.subscribers:
await broadcast(delay_s)
await Sampler.broadcast_all()
# TODO: write new data to tsdb to be ready to for next read.
@ -1037,7 +1032,7 @@ async def allocate_persistent_feed(
# insert 1s ohlc into the increment buffer set
# to update and shift every second
sampler.ohlcv_shms.setdefault(
Sampler.ohlcv_shms.setdefault(
1,
[]
).append(rt_shm)
@ -1053,13 +1048,13 @@ async def allocate_persistent_feed(
# insert 1m ohlc into the increment buffer set
# to shift every 60s.
sampler.ohlcv_shms.setdefault(60, []).append(hist_shm)
Sampler.ohlcv_shms.setdefault(60, []).append(hist_shm)
# create buffer a single incrementer task broker backend
# (aka `brokerd`) using the lowest sampler period.
if sampler.incrementers.get(_default_delay_s) is None:
if Sampler.incrementers.get(_default_delay_s) is None:
await bus.start_task(
increment_ohlc_buffer,
Sampler.increment_ohlc_buffer,
_default_delay_s,
)