feat(V2): migrazione common/ (indicators, options, microstructure, stats, http, audit, logging, mcp_bridge + auth)

src/cerbero_mcp/common/http.py

@@ -0,0 +1,85 @@
+"""HTTP client factory con retry/backoff su errori transient.
+
+Wrap leggero attorno a httpx.AsyncClient: aggiunge AsyncHTTPTransport
+con retries=N per gestire connection errors / DNS / refused. Per retry
+su 5xx HTTP response usa `request_with_retry()` (decoratore separato).
+
+Usage standard:
+
+    async with async_client(timeout=15) as http:
+        resp = await http.get(url)
+
+Equivalente a httpx.AsyncClient(timeout=15) ma con retry transport su
+errori di livello connessione.
+"""
+from __future__ import annotations
+
+import asyncio
+import logging
+from collections.abc import Awaitable, Callable
+from typing import Any, TypeVar
+
+import httpx
+
+logger = logging.getLogger(__name__)
+
+T = TypeVar("T")
+
+DEFAULT_RETRIES = 3
+DEFAULT_TIMEOUT = 15.0
+
+
+def async_client(
+    *,
+    timeout: float = DEFAULT_TIMEOUT,
+    retries: int = DEFAULT_RETRIES,
+    follow_redirects: bool = False,
+    **kwargs: Any,
+) -> httpx.AsyncClient:
+    """httpx.AsyncClient con AsyncHTTPTransport(retries=N) di default.
+    retries gestisce connection errors / refused / DNS — non 5xx HTTP.
+    """
+    transport = httpx.AsyncHTTPTransport(retries=retries)
+    return httpx.AsyncClient(
+        timeout=timeout,
+        transport=transport,
+        follow_redirects=follow_redirects,
+        **kwargs,
+    )
+
+
+async def call_with_retry(
+    fn: Callable[[], Awaitable[T]],
+    *,
+    max_attempts: int = 3,
+    base_delay: float = 0.5,
+    max_delay: float = 8.0,
+    retry_on: tuple[type[BaseException], ...] = (httpx.TransportError, httpx.TimeoutException),
+) -> T:
+    """Retry generico async con exponential backoff.
+
+    Ritenta `fn()` se solleva una delle exception in `retry_on`. Backoff
+    raddoppia (0.5, 1, 2, 4, ...) clipped a max_delay. Solleva l'ultima
+    exception se max_attempts raggiunto.
+
+    Usabile su SDK sincroni avvolti in asyncio.to_thread (pybit, alpaca):
+
+        result = await call_with_retry(lambda: client._run(self._http.get_tickers, ...))
+    """
+    delay = base_delay
+    last_exc: BaseException | None = None
+    for attempt in range(1, max_attempts + 1):
+        try:
+            return await fn()
+        except retry_on as e:
+            last_exc = e
+            if attempt == max_attempts:
+                break
+            logger.warning(
+                "transient error, retrying (%d/%d) in %.1fs: %s",
+                attempt, max_attempts, delay, type(e).__name__,
+            )
+            await asyncio.sleep(delay)
+            delay = min(delay * 2, max_delay)
+    assert last_exc is not None
+    raise last_exc