Deribit api key changes introduce:

- `get_timestamp_int`: added this is the hack, so we can aboid use the custom deribit date format.

- `get_currencies`: added so we could get all deribit's available currencies.

- Also a couple of format fixes.

piker/brokers/__init__.py

@@ -51,6 +51,7 @@ __brokers__: list[str] = [
     'ib',
     'kraken',
     'kucoin',
+    'deribit',
 
     # broken but used to work
     # 'questrade',
@@ -61,7 +62,6 @@ __brokers__: list[str] = [
     # wstrade
     # iex
 
-    # deribit
     # bitso
 ]
 

piker/brokers/deribit/__init__.py

@@ -25,6 +25,7 @@ from .api import (
     get_client,
 )
 from .feed import (
+    get_mkt_info,
     open_history_client,
     open_symbol_search,
     stream_quotes,
@@ -34,15 +35,20 @@ from .feed import (
     # open_trade_dialog,
     # norm_trade_records,
 # )
+from .venues import (
+    OptionPair,
+)
 
 log = get_logger(__name__)
 
 __all__ = [
     'get_client',
 #    'trades_dialogue',
+    'get_mkt_info',
     'open_history_client',
     'open_symbol_search',
     'stream_quotes',
+    'OptionPair',
 #    'norm_trade_records',
 ]
 

piker/brokers/deribit/feed.py

@@ -18,38 +18,59 @@
 Deribit backend.
 
 '''
+from __future__ import annotations
 from contextlib import asynccontextmanager as acm
 from datetime import datetime
-from typing import Any, Optional, Callable
+from typing import (
+    # Any,
+    # Optional,
+    Callable,
+)
+# from pprint import pformat
 import time
 
+import cryptofeed
 import trio
 from trio_typing import TaskStatus
-import pendulum
+from pendulum import (
-from rapidfuzz import process as fuzzy
+    from_timestamp,
+)
 import numpy as np
 import tractor
 
-from piker.brokers import open_cached_client
+from piker.accounting import (
-from piker.log import get_logger, get_console_log
+    Asset,
-from piker.data import ShmArray
+    MktPair,
-from piker.brokers._util import (
+    unpack_fqme,
-    BrokerError,
+)
+from piker.brokers import (
+    open_cached_client,
+    NoData,
     DataUnavailable,
 )
-
+from piker._cacheables import (
-from cryptofeed import FeedHandler
+    async_lifo_cache,
-from cryptofeed.defines import (
-    DERIBIT, L1_BOOK, TRADES, OPTION, CALL, PUT
 )
-from cryptofeed.symbols import Symbol
+from piker.log import (
+    get_logger,
+    mk_repr,
+)
+from piker.data.validate import FeedInit
+
 
 from .api import (
-    Client, Trade,
+    Client,
-    get_config,
+    # get_config,
-    str_to_cb_sym, piker_sym_to_cb_sym, cb_sym_to_deribit_inst,
+    piker_sym_to_cb_sym,
+    cb_sym_to_deribit_inst,
+    str_to_cb_sym,
     maybe_open_price_feed
 )
+from .venues import (
+    Pair,
+    OptionPair,
+    Trade,
+)
 
 _spawn_kwargs = {
     'infect_asyncio': True,
@@ -64,90 +85,215 @@ async def open_history_client(
     mkt: MktPair,
 ) -> tuple[Callable, int]:
 
-    fnstrument: str = mkt.bs_fqme
     # TODO implement history getter for the new storage layer.
     async with open_cached_client('deribit') as client:
 
+        pair: OptionPair = client._pairs[mkt.dst.name]
+        # XXX NOTE, the cuckers use ms !!!
+        creation_time_s: int = pair.creation_timestamp/1000
+
         async def get_ohlc(
-            end_dt: Optional[datetime] = None,
+            timeframe: float,
-            start_dt: Optional[datetime] = None,
+            end_dt: datetime | None = None,
+            start_dt: datetime | None = None,
 
         ) -> tuple[
             np.ndarray,
             datetime,  # start
             datetime,  # end
         ]:
+            if timeframe != 60:
+                raise DataUnavailable('Only 1m bars are supported')
 
-            array = await client.bars(
+            array: np.ndarray = await client.bars(
-                instrument,
+                mkt,
                 start_dt=start_dt,
                 end_dt=end_dt,
             )
             if len(array) == 0:
-                raise DataUnavailable
+                if (
+                    end_dt is None
+                ):
+                    raise DataUnavailable(
+                        'No history seems to exist yet?\n\n'
+                        f'{mkt}'
+                    )
+                elif (
+                    end_dt
+                    and
+                    end_dt.timestamp() < creation_time_s
+                ):
+                    # the contract can't have history
+                    # before it was created.
+                    pair_type_str: str = type(pair).__name__
+                    create_dt: datetime = from_timestamp(creation_time_s)
+                    raise DataUnavailable(
+                        f'No history prior to\n'
+                        f'`{pair_type_str}.creation_timestamp: int = '
+                        f'{pair.creation_timestamp}\n\n'
+                        f'------ deribit sux ------\n'
+                        f'WHICH IN "NORMAL PEOPLE WHO USE EPOCH TIME" form is,\n'
+                        f'creation_time_s: {creation_time_s}\n'
+                        f'create_dt: {create_dt}\n'
+                    )
+                raise NoData(
+                    f'No frame for {start_dt} -> {end_dt}\n'
+                )
 
-            start_dt = pendulum.from_timestamp(array[0]['time'])
+            start_dt = from_timestamp(array[0]['time'])
-            end_dt = pendulum.from_timestamp(array[-1]['time'])
+            end_dt = from_timestamp(array[-1]['time'])
+
+            times = array['time']
+            if not times.any():
+                raise ValueError(
+                    'Bad frame with null-times?\n\n'
+                    f'{times}'
+                )
+
+            if end_dt is None:
+                inow: int = round(time.time())
+                if (inow - times[-1]) > 60:
+                    await tractor.pause()
 
             return array, start_dt, end_dt
 
-        yield get_ohlc, {'erlangs': 3, 'rate': 3}
+        yield (
+            get_ohlc,
+            {  # backfill config
+                'erlangs': 3,
+                'rate': 3,
+            }
+        )
+
+
+@async_lifo_cache()
+async def get_mkt_info(
+    fqme: str,
+
+) -> tuple[MktPair, Pair|OptionPair] | None:
+
+    # uppercase since kraken bs_mktid is always upper
+    if 'deribit' not in fqme.lower():
+        fqme += '.deribit'
+
+    mkt_mode: str = ''
+    broker, mkt_ep, venue, expiry = unpack_fqme(fqme)
+
+    # NOTE: we always upper case all tokens to be consistent with
+    # binance's symbology style for pairs, like `BTCUSDT`, but in
+    # theory we could also just keep things lower case; as long as
+    # we're consistent and the symcache matches whatever this func
+    # returns, always!
+    expiry: str = expiry.upper()
+    venue: str = venue.upper()
+    # venue_lower: str = venue.lower()
+
+    mkt_mode: str = 'option'
+
+    async with open_cached_client(
+        'deribit',
+    ) as client:
+
+        assets: dict[str, Asset] = await client.get_assets()
+        pair_str: str = mkt_ep.lower()
+
+        pair: Pair = await client.exch_info(
+            sym=pair_str,
+        )
+        mkt_mode = pair.venue
+        client.mkt_mode = mkt_mode
+
+        dst: Asset | None = assets.get(pair.bs_dst_asset)
+        src: Asset | None = assets.get(pair.bs_src_asset)
+
+        mkt = MktPair(
+            dst=dst,
+            src=src,
+            price_tick=pair.price_tick,
+            size_tick=pair.size_tick,
+            bs_mktid=pair.symbol,
+            venue=mkt_mode,
+            broker='deribit',
+            _atype=mkt_mode,
+            _fqme_without_src=True,
+
+            # expiry=pair.expiry,
+            # XXX TODO, currently we don't use it since it's
+            # already "described" in the `OptionPair.symbol: str`
+            # and if we slap in the ISO repr it's kinda hideous..
+            # -[ ] figure out the best either std
+        )
+        return mkt, pair
 
 
 async def stream_quotes(
-
     send_chan: trio.abc.SendChannel,
     symbols: list[str],
     feed_is_live: trio.Event,
-    loglevel: str = None,
 
     # startup sync
     task_status: TaskStatus[tuple[dict, dict]] = trio.TASK_STATUS_IGNORED,
 
 ) -> None:
-    # XXX: required to propagate ``tractor`` loglevel to piker logging
+    '''
-    get_console_log(loglevel or tractor.current_actor().loglevel)
+    Open a live quote stream for the market set defined by `symbols`.
 
-    sym = symbols[0]
+    Internally this starts a `cryptofeed.FeedHandler` inside an `asyncio`-side
+    task and relays through L1 and `Trade` msgs here to our `trio.Task`.
+
+    '''
+    sym = symbols[0].split('.')[0]
+    init_msgs: list[FeedInit] = []
+
+    # multiline nested `dict` formatter (since rn quote-msgs are
+    # just that).
+    pfmt: Callable[[str], str] = mk_repr(
+        # so we can see `deribit`'s delightfully mega-long bs fields..
+        maxstring=100,
+    )
 
     async with (
         open_cached_client('deribit') as client,
         send_chan as send_chan
     ):
+        mkt: MktPair
+        pair: Pair
+        mkt, pair = await get_mkt_info(sym)
 
-        init_msgs = {
+        # build out init msgs according to latest spec
-            # pass back token, and bool, signalling if we're the writer
+        init_msgs.append(
-            # and that history has been written
+            FeedInit(
-            sym: {
+                mkt_info=mkt,
-                'symbol_info': {
+            )
-                    'asset_type': 'option',
+        )
-                    'price_tick_size': 0.0005
+        # build `cryptofeed` feed-handle
-                },
+        cf_sym: cryptofeed.Symbol = piker_sym_to_cb_sym(sym)
-                'shm_write_opts': {'sum_tick_vml': False},
-                'fqsn': sym,
-            },
-        }
 
-        nsym = piker_sym_to_cb_sym(sym)
+        from_cf: tractor.to_asyncio.LinkedTaskChannel
+        async with maybe_open_price_feed(sym) as from_cf:
 
-        async with maybe_open_price_feed(sym) as stream:
+            # load the "last trades" summary
+            last_trades_res: cryptofeed.LastTradesResult = await client.last_trades(
+                cb_sym_to_deribit_inst(cf_sym),
+                count=1,
+            )
+            last_trades: list[Trade] = last_trades_res.trades
 
-            cache = await client.cache_symbols()
+            # TODO, do we even need this or will the above always
+            # work?
+            # if not last_trades:
+            #     await tractor.pause()
+            #     async for typ, quote in from_cf:
+            #         if typ == 'trade':
+            #             last_trade = Trade(**(quote['data']))
+            #             break
 
-            last_trades = (await client.last_trades(
+            # else:
-                cb_sym_to_deribit_inst(nsym), count=1)).trades
+            last_trade = Trade(
+                **(last_trades[0])
+            )
 
-            if len(last_trades) == 0:
+            first_quote: dict = {
-                last_trade = None
-                async for typ, quote in stream:
-                    if typ == 'trade':
-                        last_trade = Trade(**(quote['data']))
-                        break
-
-            else:
-                last_trade = Trade(**(last_trades[0]))
-
-            first_quote = {
                 'symbol': sym,
                 'last': last_trade.price,
                 'brokerd_ts': last_trade.timestamp,
@@ -158,13 +304,84 @@ async def stream_quotes(
                     'broker_ts': last_trade.timestamp
                 }]
             }
-            task_status.started((init_msgs,  first_quote))
+            task_status.started((
+                init_msgs,
+                first_quote,
+            ))
 
             feed_is_live.set()
 
-            async for typ, quote in stream:
+            # NOTE XXX, static for now!
-                topic = quote['symbol']
+            # => since this only handles ONE mkt feed at a time we
-                await send_chan.send({topic: quote})
+            # don't need a lookup table to map interleaved quotes
+            # from multiple possible mkt-pairs
+            topic: str = mkt.bs_fqme
+
+            # deliver until cancelled
+            async for typ, ref in from_cf:
+                match typ:
+                    case 'trade':
+                        trade: cryptofeed.types.Trade = ref
+
+                        # TODO, re-impl this according to teh ideal
+                        # fqme for opts that we choose!!
+                        bs_fqme: str = cb_sym_to_deribit_inst(
+                            str_to_cb_sym(trade.symbol)
+                        ).lower()
+
+                        piker_quote: dict = {
+                            'symbol': bs_fqme,
+                            'last': trade.price,
+                            'broker_ts': time.time(),
+                            # ^TODO, name this `brokerd/datad_ts` and
+                            # use `time.time_ns()` ??
+                            'ticks': [{
+                                'type': 'trade',
+                                'price': float(trade.price),
+                                'size': float(trade.amount),
+                                'broker_ts': trade.timestamp,
+                            }],
+                        }
+                        log.info(
+                            f'deribit {typ!r} quote for {sym!r}\n\n'
+                            f'{trade}\n\n'
+                            f'{pfmt(piker_quote)}\n'
+                        )
+
+                    case 'l1':
+                        book: cryptofeed.types.L1Book = ref
+
+                        # TODO, so this is where we can possibly change things
+                        # and instead lever the `MktPair.bs_fqme: str` output?
+                        bs_fqme: str = cb_sym_to_deribit_inst(
+                            str_to_cb_sym(book.symbol)
+                        ).lower()
+
+                        piker_quote: dict = {
+                            'symbol': bs_fqme,
+                            'ticks': [
+
+                                {'type': 'bid',
+                                 'price': float(book.bid_price),
+                                 'size': float(book.bid_size)},
+
+                                {'type': 'bsize',
+                                 'price': float(book.bid_price),
+                                 'size': float(book.bid_size),},
+
+                                {'type': 'ask',
+                                 'price': float(book.ask_price),
+                                 'size': float(book.ask_size),},
+
+                                {'type': 'asize',
+                                 'price': float(book.ask_price),
+                                 'size': float(book.ask_size),}
+                            ]
+                        }
+
+                await send_chan.send({
+                    topic: piker_quote,
+                })
 
 
 @tractor.context
@@ -174,12 +391,21 @@ async def open_symbol_search(
     async with open_cached_client('deribit') as client:
 
         # load all symbols locally for fast search
-        cache = await client.cache_symbols()
+        # cache = client._pairs
         await ctx.started()
 
         async with ctx.open_stream() as stream:
-
+            pattern: str
             async for pattern in stream:
-                # repack in dict form
+
-                await stream.send(
+                # NOTE: pattern fuzzy-matching is done within
-                    await client.search_symbols(pattern))
+                # the methd impl.
+                pairs: dict[str, Pair] = await client.search_symbols(
+                    pattern,
+                )
+                # repack in fqme-keyed table
+                byfqme: dict[str, Pair] = {}
+                for pair in pairs.values():
+                    byfqme[pair.bs_fqme] = pair
+
+                await stream.send(byfqme)

piker/brokers/deribit/venues.py

@@ -0,0 +1,196 @@
+# 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/>.
+
+"""
+Per market data-type definitions and schemas types.
+
+"""
+from __future__ import annotations
+import pendulum
+from typing import (
+    Literal,
+    Optional,
+)
+from decimal import Decimal
+
+from piker.types import Struct
+
+
+# API endpoint paths by venue / sub-API
+_domain: str = 'deribit.com'
+_url = f'https://www.{_domain}'
+
+# WEBsocketz
+_ws_url: str = f'wss://www.{_domain}/ws/api/v2'
+
+# test nets
+_testnet_ws_url: str = f'wss://test.{_domain}/ws/api/v2'
+
+MarketType = Literal[
+    'option'
+]
+
+
+def get_api_eps(venue: MarketType) -> tuple[str, str]:
+    '''
+    Return API ep root paths per venue.
+
+    '''
+    return {
+        'option': (
+            _ws_url,
+        ),
+    }[venue]
+
+
+class Pair(Struct, frozen=True, kw_only=True):
+
+    symbol: str
+
+    # src
+    quote_currency: str # 'BTC'
+
+    # dst
+    base_currency: str # "BTC",
+
+    tick_size: float # 0.0001 # [{'above_price': 0.005, 'tick_size': 0.0005}]
+    tick_size_steps: list[dict[str, float]] 
+
+    @property
+    def price_tick(self) -> Decimal:
+        return Decimal(str(self.tick_size_steps[0]['above_price']))
+
+    @property
+    def size_tick(self) -> Decimal:
+        return Decimal(str(self.tick_size))
+
+    @property
+    def bs_fqme(self) -> str:
+        return f'{self.symbol}'
+
+    @property
+    def bs_mktid(self) -> str:
+        return f'{self.symbol}.{self.venue}'
+
+
+class OptionPair(Pair, frozen=True):
+
+    taker_commission: float # 0.0003
+    strike: float # 5000.0
+    settlement_period: str # 'day'
+    settlement_currency: str # "BTC",
+    rfq: bool # false
+    price_index: str # 'btc_usd'
+    option_type: str # 'call'
+    min_trade_amount: float # 0.1
+    maker_commission: float # 0.0003
+    kind: str # 'option'
+    is_active: bool # true
+    instrument_type: str # 'reversed'
+    instrument_name: str # 'BTC-1SEP24-55000-C'
+    instrument_id: int # 364671
+    expiration_timestamp: int # 1725177600000
+    creation_timestamp: int # 1724918461000
+    counter_currency: str # 'USD' 
+    contract_size: float # '1.0'
+    block_trade_tick_size: float # '0.0001'
+    block_trade_min_trade_amount: int # '25'
+    block_trade_commission: float # '0.003'
+
+    # NOTE: see `.data._symcache.SymbologyCache.load()` for why
+    ns_path: str = 'piker.brokers.deribit:OptionPair'
+
+    # TODO, impl this without the MM:SS part of
+    # the `'THH:MM:SS..'` etc..
+    @property
+    def expiry(self) -> str:
+        iso_date = pendulum.from_timestamp(
+            self.expiration_timestamp / 1000
+        ).isoformat()
+        return iso_date 
+
+    @property
+    def venue(self) -> str:
+        return f'{self.instrument_type}_option'
+
+    @property
+    def bs_fqme(self) -> str:
+        return f'{self.symbol}'
+
+    @property
+    def bs_src_asset(self) -> str:
+        return f'{self.quote_currency}'
+
+    @property
+    def bs_dst_asset(self) -> str:
+        return f'{self.symbol}'
+
+
+PAIRTYPES: dict[MarketType, Pair] = {
+    'option': OptionPair,
+}
+
+
+class JSONRPCResult(Struct):
+    id: int
+    usIn: int
+    usOut: int
+    usDiff: int
+    testnet: bool
+    jsonrpc: str = '2.0'
+    error: Optional[dict] = None
+    result: Optional[list[dict]] = None
+
+
+class JSONRPCChannel(Struct):
+    method: str
+    params: dict
+    jsonrpc: str = '2.0'
+
+
+class KLinesResult(Struct):
+    low: list[float]
+    cost: list[float]
+    high: list[float]
+    open: list[float]
+    close: list[float]
+    ticks: list[int]
+    status: str
+    volume: list[float]
+
+
+class Trade(Struct):
+    iv: float
+    price: float
+    amount: float
+    trade_id: str
+    contracts: float
+    direction: str
+    trade_seq: int
+    timestamp: int
+    mark_price: float
+    index_price: float
+    tick_direction: int
+    instrument_name: str
+    combo_id: Optional[str] = '',
+    combo_trade_id: Optional[int] = 0,
+    block_trade_id: Optional[str] = '',
+    block_trade_leg_count: Optional[int] = 0,
+
+
+class LastTradesResult(Struct):
+    trades: list[Trade]
+    has_more: bool

piker/data/_web_bs.py

@@ -360,7 +360,7 @@ async def open_autorecon_ws(
 
 '''
 JSONRPC response-request style machinery for transparent multiplexing
-of msgs over a NoBsWs.
+of msgs over a `NoBsWs`.
 
 '''
 
@@ -377,6 +377,16 @@ async def open_jsonrpc_session(
     url: str,
     start_id: int = 0,
     response_type: type = JSONRPCResult,
+    msg_recv_timeout: float = float('inf'),
+    # ^NOTE, since only `deribit` is using this jsonrpc stuff atm
+    # and options mkts are generally "slow moving"..
+    #
+    # FURTHER if we break the underlying ws connection then since we
+    # don't pass a `fixture` to the task that manages `NoBsWs`, i.e.
+    # `_reconnect_forever()`, the jsonrpc "transport pipe" get's
+    # broken and never restored with wtv init sequence is required to
+    # re-establish a working req-resp session.
+
 ) -> Callable[[str, dict], dict]:
     '''
     Init a json-RPC-over-websocket connection to the provided `url`.
@@ -393,12 +403,18 @@ async def open_jsonrpc_session(
 
     async with (
         trio.open_nursery() as tn,
-        open_autorecon_ws(url) as ws
+        open_autorecon_ws(
+            url=url,
+            msg_recv_timeout=msg_recv_timeout,
+        ) as ws
     ):
         rpc_id: Iterable[int] = count(start_id)
         rpc_results: dict[int, dict] = {}
 
-        async def json_rpc(method: str, params: dict) -> dict:
+        async def json_rpc(
+            method: str,
+            params: dict,
+        ) -> dict:
             '''
             perform a json rpc call and wait for the result, raise exception in
             case of error field present on response

piker/tsp/__init__.py

@@ -44,8 +44,10 @@ import trio
 from trio_typing import TaskStatus
 import tractor
 from pendulum import (
+    Interval,
     DateTime,
     Duration,
+    duration as mk_duration,
     from_timestamp,
 )
 import numpy as np
@@ -214,7 +216,8 @@ async def maybe_fill_null_segments(
         # pair, immediately stop backfilling?
         if (
             start_dt
-            and end_dt < start_dt
+            and
+            end_dt < start_dt
         ):
             await tractor.pause()
             break
@@ -262,6 +265,7 @@ async def maybe_fill_null_segments(
         except tractor.ContextCancelled:
             # log.exception
             await tractor.pause()
+            raise
 
     null_segs_detected.set()
     # RECHECK for more null-gaps
@@ -349,7 +353,7 @@ async def maybe_fill_null_segments(
 
 async def start_backfill(
     get_hist,
-    frame_types: dict[str, Duration] | None,
+    def_frame_duration: Duration,
     mod: ModuleType,
     mkt: MktPair,
     shm: ShmArray,
@@ -379,22 +383,23 @@ async def start_backfill(
         update_start_on_prepend: bool = False
         if backfill_until_dt is None:
 
-            # TODO: drop this right and just expose the backfill
+            # TODO: per-provider default history-durations?
-            # limits inside a [storage] section in conf.toml?
+            # -[ ] inside the `open_history_client()` config allow
-            # when no tsdb "last datum" is provided, we just load
+            #    declaring the history duration limits instead of
-            # some near-term history.
+            #    guessing and/or applying the same limits to all?
-            # periods = {
+            #
-            #     1: {'days': 1},
+            # -[ ] allow declaring (default) per-provider backfill
-            #     60: {'days': 14},
+            #     limits inside a [storage] sub-section in conf.toml?
-            # }
+            #
-
+            # NOTE, when no tsdb "last datum" is provided, we just
-            # do a decently sized backfill and load it into storage.
+            # load some near-term history by presuming a "decently
+            # large" 60s duration limit and a much shorter 1s range.
             periods = {
                 1: {'days': 2},
                 60: {'years': 6},
             }
             period_duration: int = periods[timeframe]
-            update_start_on_prepend = True
+            update_start_on_prepend: bool = True
 
             # NOTE: manually set the "latest" datetime which we intend to
             # backfill history "until" so as to adhere to the history
@@ -416,7 +421,6 @@ async def start_backfill(
                 f'backfill_until_dt: {backfill_until_dt}\n'
                 f'last_start_dt: {last_start_dt}\n'
             )
-
             try:
                 (
                     array,
@@ -426,37 +430,58 @@ async def start_backfill(
                     timeframe,
                     end_dt=last_start_dt,
                 )
-
             except NoData as _daterr:
-                # 3 cases:
+                orig_last_start_dt: datetime = last_start_dt
-                # - frame in the middle of a legit venue gap
+                gap_report: str = (
-                # - history actually began at the `last_start_dt`
+                    f'EMPTY FRAME for `end_dt: {last_start_dt}`?\n'
-                # - some other unknown error (ib blocking the
+                    f'{mod.name} -> tf@fqme: {timeframe}@{mkt.fqme}\n'
-                #   history bc they don't want you seeing how they
+                    f'last_start_dt: {orig_last_start_dt}\n\n'
-                #   cucked all the tinas..)
+                    f'bf_until: {backfill_until_dt}\n'
-                if dur := frame_types.get(timeframe):
+                )
-                    # decrement by a frame's worth of duration and
+                # EMPTY FRAME signal with 3 (likely) causes:
-                    # retry a few times.
+                #
-                    last_start_dt.subtract(
+                # 1. range contains legit gap in venue history
-                        seconds=dur.total_seconds()
+                # 2. history actually (edge case) **began** at the
+                #    value `last_start_dt`
+                # 3. some other unknown error (ib blocking the
+                #    history-query bc they don't want you seeing how
+                #    they cucked all the tinas.. like with options
+                #    hist)
+                #
+                if def_frame_duration:
+                    # decrement by a duration's (frame) worth of time
+                    # as maybe indicated by the backend to see if we
+                    # can get older data before this possible
+                    # "history gap".
+                    last_start_dt: datetime = last_start_dt.subtract(
+                        seconds=def_frame_duration.total_seconds()
                     )
-                    log.warning(
+                    gap_report += (
-                        f'{mod.name} -> EMPTY FRAME for end_dt?\n'
+                        f'Decrementing `end_dt` and retrying with,\n'
-                        f'tf@fqme: {timeframe}@{mkt.fqme}\n'
+                        f'def_frame_duration: {def_frame_duration}\n'
-                        'bf_until <- last_start_dt:\n'
+                        f'(new) last_start_dt: {last_start_dt}\n'
-                        f'{backfill_until_dt} <- {last_start_dt}\n'
-                        f'Decrementing `end_dt` by {dur} and retry..\n'
                     )
+                    log.warning(gap_report)
+                    # skip writing to shm/tsdb and try the next
+                    # duration's worth of prior history.
                     continue
 
+                else:
+                    # await tractor.pause()
+                    raise DataUnavailable(gap_report)
+
             # broker says there never was or is no more history to pull
-            except DataUnavailable:
+            except DataUnavailable as due:
+                message: str = due.args[0]
                 log.warning(
-                    f'NO-MORE-DATA in range?\n'
+                    f'Provider {mod.name!r} halted backfill due to,\n\n'
-                    f'`{mod.name}` halted history:\n'
+
-                    f'tf@fqme: {timeframe}@{mkt.fqme}\n'
+                    f'{message}\n'
-                    'bf_until <- last_start_dt:\n'
+
-                    f'{backfill_until_dt} <- {last_start_dt}\n'
+                    f'fqme: {mkt.fqme}\n'
+                    f'timeframe: {timeframe}\n'
+                    f'last_start_dt: {last_start_dt}\n'
+                    f'bf_until: {backfill_until_dt}\n'
                 )
                 # UGH: what's a better way?
                 # TODO: backends are responsible for being correct on
@@ -465,34 +490,54 @@ async def start_backfill(
                 #     to halt the request loop until the condition is
                 #     resolved or should the backend be entirely in
                 #     charge of solving such faults? yes, right?
-                # if timeframe > 1:
-                #     await tractor.pause()
                 return
 
+            time: np.ndarray = array['time']
             assert (
-                array['time'][0]
+                time[0]
                 ==
                 next_start_dt.timestamp()
             )
 
-            diff = last_start_dt - next_start_dt
+            assert time[-1] == next_end_dt.timestamp()
-            frame_time_diff_s = diff.seconds
+
+            expected_dur: Interval = last_start_dt - next_start_dt
 
             # frame's worth of sample-period-steps, in seconds
             frame_size_s: float = len(array) * timeframe
-            expected_frame_size_s: float = frame_size_s + timeframe
+            recv_frame_dur: Duration = (
-            if frame_time_diff_s > expected_frame_size_s:
+                from_timestamp(array[-1]['time'])
-
+                -
+                from_timestamp(array[0]['time'])
+            )
+            if (
+                (lt_frame := (recv_frame_dur < expected_dur))
+                or
+                (null_frame := (frame_size_s == 0))
+                # ^XXX, should NEVER hit now!
+            ):
                 # XXX: query result includes a start point prior to our
                 # expected "frame size" and thus is likely some kind of
                 # history gap (eg. market closed period, outage, etc.)
                 # so just report it to console for now.
+                if lt_frame:
+                    reason = 'Possible GAP (or first-datum)'
+                else:
+                    assert null_frame
+                    reason = 'NULL-FRAME'
+
+                missing_dur: Interval = expected_dur.end - recv_frame_dur.end
                 log.warning(
-                    'GAP DETECTED:\n'
+                    f'{timeframe}s-series {reason} detected!\n'
-                    f'last_start_dt: {last_start_dt}\n'
+                    f'fqme: {mkt.fqme}\n'
-                    f'diff: {diff}\n'
+                    f'last_start_dt: {last_start_dt}\n\n'
-                    f'frame_time_diff_s: {frame_time_diff_s}\n'
+                    f'recv interval: {recv_frame_dur}\n'
+                    f'expected interval: {expected_dur}\n\n'
+
+                    f'Missing duration of history of {missing_dur.in_words()!r}\n'
+                    f'{missing_dur}\n'
                 )
+                # await tractor.pause()
 
             to_push = diff_history(
                 array,
@@ -567,7 +612,8 @@ async def start_backfill(
             # long-term storage.
             if (
                 storage is not None
-                and write_tsdb
+                and
+                write_tsdb
             ):
                 log.info(
                     f'Writing {ln} frame to storage:\n'
@@ -691,7 +737,7 @@ async def back_load_from_tsdb(
         last_tsdb_dt
         and latest_start_dt
     ):
-        backfilled_size_s = (
+        backfilled_size_s: Duration = (
             latest_start_dt - last_tsdb_dt
         ).seconds
         # if the shm buffer len is not large enough to contain
@@ -914,6 +960,8 @@ async def tsdb_backfill(
             f'{pformat(config)}\n'
         )
 
+        # concurrently load the provider's most-recent-frame AND any
+        # pre-existing tsdb history already saved in `piker` storage.
         dt_eps: list[DateTime, DateTime] = []
         async with trio.open_nursery() as tn:
             tn.start_soon(
@@ -924,7 +972,6 @@ async def tsdb_backfill(
                 timeframe,
                 config,
             )
-
             tsdb_entry: tuple = await load_tsdb_hist(
                 storage,
                 mkt,
@@ -953,6 +1000,25 @@ async def tsdb_backfill(
                 mr_end_dt,
             ) = dt_eps
 
+            first_frame_dur_s: Duration = (mr_end_dt - mr_start_dt).seconds
+            calced_frame_size: Duration = mk_duration(
+                seconds=first_frame_dur_s,
+            )
+            # NOTE, attempt to use the backend declared default frame
+            # sizing (as allowed by their time-series query APIs) and
+            # if not provided try to construct a default from the
+            # first frame received above.
+            def_frame_durs: dict[
+                int,
+                Duration,
+            ]|None = config.get('frame_types', None)
+            if def_frame_durs:
+                def_frame_size: Duration = def_frame_durs[timeframe]
+                assert def_frame_size == calced_frame_size
+            else:
+                # use what we calced from first frame above.
+                def_frame_size = calced_frame_size
+
             # NOTE: when there's no offline data, there's 2 cases:
             # - data backend doesn't support timeframe/sample
             #   period (in which case `dt_eps` should be `None` and
@@ -983,7 +1049,7 @@ async def tsdb_backfill(
                     partial(
                         start_backfill,
                         get_hist=get_hist,
-                        frame_types=config.get('frame_types', None),
+                        def_frame_duration=def_frame_size,
                         mod=mod,
                         mkt=mkt,
                         shm=shm,