add get_market_info

piker/brokers/deribit/feed.py

@@ -130,6 +130,73 @@ async def open_history_client(
         yield get_ohlc, {'erlangs': 3, 'rate': 3}
 
 
+@async_lifo_cache()
+async def get_mkt_info(
+    fqme: str,
+
+) -> tuple[MktPair, Pair] | 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()
+
+        # switch venue-mode depending on input pattern parsing
+        # since we want to use a particular endpoint (set) for
+        # pair info lookup!
+        client.mkt_mode = mkt_mode
+
+        pair: Pair = await client.exch_info(
+            sym=pair_str,
+        )
+        dst: Asset | None = assets.get(pair.bs_dst_asset)
+        if (
+            not dst
+            # TODO: a known asset DNE list?
+            # and pair.baseAsset == 'DEFI'
+        ):
+            log.warning(
+                f'UNKNOWN {venue} asset {pair.base_currency} from,\n'
+                f'{pformat(pair.to_dict())}'
+            )
+
+            # XXX UNKNOWN missing "asset", though no idea why?
+            # maybe it's only avail in the margin venue(s): /dapi/ ?
+            return None
+
+        mkt = MktPair(
+            dst=dst,
+            src=assets.get(pair.bs_src_asset),
+            price_tick=pair.price_tick,
+            size_tick=pair.size_tick,
+            bs_mktid=pair.symbol,
+            expiry=expiry,
+            venue=venue,
+            broker='deribit',
+        )
+        return mkt, pair
+
+
 async def stream_quotes(
 
     send_chan: trio.abc.SendChannel,