fix: harden wallet balances and service startup

src/infrastructure/wallet_balances/service.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import asyncio
 import hashlib
+import time
 from dataclasses import dataclass
 from decimal import Decimal, InvalidOperation
 from typing import Any
@@ -19,6 +20,8 @@ from src.infrastructure.wallet_balances.token_registry import (
 )
 
 TIMEOUT_SECONDS = 15
+RETRY_ATTEMPTS = 2
+PRICE_CACHE_SECONDS = 30
 BLOCKSTREAM_URL = 'https://blockstream.info/api'
 TRONGRID_URL = 'https://api.trongrid.io'
 COINGECKO_URL = 'https://api.coingecko.com/api/v3/simple/price'
@@ -49,6 +52,10 @@ class WalletBalance:
 
 
 class WalletBalanceService:
+    def __init__(self) -> None:
+        self._prices_cache: dict[tuple[tuple[str,str],...],tuple[float,dict[str,Decimal | None]]] = {}
+
+
     async def get_wallet_balances(self, wallets) -> list[WalletBalance]:
         prices = await self._get_prices(wallets)
         results = await asyncio.gather(
@@ -193,10 +200,17 @@ class WalletBalanceService:
             for token in self._tokens_for_chain(chain):
                 coin_id = get_coingecko_id(chain, token['symbol'])
                 if coin_id:
-                    pairs[f'{chain}:{token['symbol']}'] = coin_id
+                    symbol = token['symbol']
+                    pairs[f'{chain}:{symbol}'] = coin_id
         if not pairs:
             return {}
 
+        cache_key = tuple(sorted(pairs.items()))
+        cached = self._prices_cache.get(cache_key)
+        now = time.monotonic()
+        if cached is not None and now - cached[0] < PRICE_CACHE_SECONDS:
+            return dict(cached[1])
+
         try:
             response = await self._get_json(
                 COINGECKO_URL,
@@ -210,10 +224,12 @@ class WalletBalanceService:
         except Exception:
             return {key: None for key in pairs}
 
-        return {
+        prices = {
             key: self._decimal_or_none((response.get(coin_id) or {}).get('usd'))
             for key, coin_id in pairs.items()
         }
+        self._prices_cache[cache_key] = (now,prices)
+        return prices
 
     def _token_amounts(
         self,
@@ -287,9 +303,16 @@ class WalletBalanceService:
         timeout: int = TIMEOUT_SECONDS,
     ) -> Any:
         async with httpx.AsyncClient(timeout=timeout) as client:
-            response = await client.get(url, params=params, headers=headers)
-            response.raise_for_status()
-            return response.json()
+            for attempt in range(RETRY_ATTEMPTS + 1):
+                try:
+                    response = await client.get(url, params=params, headers=headers)
+                    response.raise_for_status()
+                    return response.json()
+                except (httpx.RequestError,httpx.HTTPStatusError,ValueError):
+                    if attempt >= RETRY_ATTEMPTS:
+                        raise
+                    await asyncio.sleep(0.2 * (attempt + 1))
+            raise RuntimeError('HTTP GET failed')
 
     async def _post_json(
         self,
@@ -300,9 +323,16 @@ class WalletBalanceService:
         timeout: int = TIMEOUT_SECONDS,
     ) -> Any:
         async with httpx.AsyncClient(timeout=timeout) as client:
-            response = await client.post(url, json=payload, headers=headers)
-            response.raise_for_status()
-            return response.json()
+            for attempt in range(RETRY_ATTEMPTS + 1):
+                try:
+                    response = await client.post(url, json=payload, headers=headers)
+                    response.raise_for_status()
+                    return response.json()
+                except (httpx.RequestError,httpx.HTTPStatusError,ValueError):
+                    if attempt >= RETRY_ATTEMPTS:
+                        raise
+                    await asyncio.sleep(0.2 * (attempt + 1))
+            raise RuntimeError('HTTP POST failed')
 
     def _tokens_for_chain(self, chain: str) -> list[dict]:
         if chain in {'ETH', 'BSC'}: