binance: spec `.ns_path: str` on pair structs

Provides for fully isolated symbology caching in a flat TOML table
without special case handling B)

Also explicitly define `.bs_mktid: str` which is now used by the
symcache to to key-index the backend specific pair set and thus provides
for round-trip marshalling without special knowledge of any backend
schema.

piker/brokers/binance/__init__.py

@@ -33,11 +33,16 @@ from .feed import (
 from .broker import (
     open_trade_dialog,
 )
-
+from .venues import (
+    SpotPair,
+    FutesPair,
+)
 
 __all__ = [
     'get_client',
     'get_mkt_info',
+    'SpotPair',
+    'FutesPair',
     'open_trade_dialog',
     'open_history_client',
     'open_symbol_search',

piker/brokers/binance/broker.py

@@ -36,7 +36,6 @@ import trio
 
 from piker.accounting import (
     Asset,
-    # MktPair,
 )
 from piker.brokers._util import (
     get_logger,
@@ -232,6 +231,9 @@ async def open_trade_dialog(
     account_name: str = 'usdtm'
     use_testnet: bool = False
 
+    # TODO: if/when we add .accounting support we need to
+    # do a open_symcache() call.. though maybe we can hide
+    # this in a new async version of open_account()?
     async with open_cached_client('binance') as client:
         subconf: dict = client.conf[venue_name]
         use_testnet = subconf.get('use_testnet', False)

piker/brokers/binance/venues.py

@@ -84,6 +84,7 @@ def get_api_eps(venue: MarketType) -> tuple[str, str]:
 
 
 class Pair(Struct, frozen=True, kw_only=True):
+
     symbol: str
     status: str
     orderTypes: list[str]
@@ -117,6 +118,10 @@ class Pair(Struct, frozen=True, kw_only=True):
     def bs_fqme(self) -> str:
         return self.symbol
 
+    @property
+    def bs_mktid(self) -> str:
+        return f'{self.symbol}.{self.venue}'
+
 
 class SpotPair(Pair, frozen=True):
 
@@ -137,6 +142,13 @@ class SpotPair(Pair, frozen=True):
     allowedSelfTradePreventionModes: list[str]
     permissions: list[str]
 
+    # NOTE: see `.data._symcache.SymbologyCache.load()` for why
+    ns_path: str = 'piker.brokers.binance:SpotPair'
+
+    @property
+    def venue(self) -> str:
+        return 'SPOT'
+
     @property
     def bs_fqme(self) -> str:
         return f'{self.symbol}.SPOT'
@@ -173,6 +185,9 @@ class FutesPair(Pair):
     underlyingSubType: list[str]  # ['PoW'],
     underlyingType: str  # 'COIN'
 
+    # NOTE: see `.data._symcache.SymbologyCache.load()` for why
+    ns_path: str = 'piker.brokers.binance:FutesPair'
+
     # NOTE: for compat with spot pairs and `MktPair.src: Asset`
     # processing..
     @property