Implement retry that automatically detect httpx and backoff (#119)

* server: implement retry that automatically detect httpx and backoff

Closes #118

* server: fix formatting

server/reflector/utils/retry.py

@@ -1,27 +1,82 @@
 from reflector.logger import logger
+from time import monotonic
+from httpx import HTTPStatusError, Response
+from random import random
 import asyncio
 
 
+class RetryException(Exception):
+    pass
+
+
+class RetryTimeoutException(RetryException):
+    pass
+
+
+class RetryHTTPException(RetryException):
+    pass
+
+
 def retry(fn):
     async def decorated(*args, **kwargs):
-        retry_max = kwargs.pop("retry_max", 5)
-        retry_delay = kwargs.pop("retry_delay", 2)
-        retry_ignore_exc_types = kwargs.pop("retry_ignore_exc_types", ())
+        retry_attempts = kwargs.pop("retry_attempts", None)
+        retry_timeout = kwargs.pop("retry_timeout", 60)
+        retry_backoff_interval = kwargs.pop("retry_backoff_interval", 0.1)
+        retry_jitter = kwargs.pop("retry_jitter", 0.1)
+        retry_backoff_max = kwargs.pop("retry_backoff_max", 3)
+        retry_httpx_status_stop = kwargs.pop(
+            "retry_httpx_status_stop",
+            (
+                401,  # auth issue
+                404,  # not found
+                413,  # payload too large
+                418,  # teapot
+            ),
+        )
+        retry_ignore_exc_types = kwargs.pop("retry_ignore_exc_types", (Exception,))
+
         result = None
-        attempt = 0
         last_exception = None
-        for attempt in range(retry_max):
+        attempts = 0
+        start = monotonic()
+        fn_name = fn.__name__
+
+        # goal: retry until timeout
+        while True:
+            if monotonic() - start > retry_timeout:
+                raise RetryTimeoutException()
+
+            jitter = random() * retry_jitter
+            retry_backoff_interval = min(
+                retry_backoff_interval * 2 + jitter, retry_backoff_max
+            )
+
             try:
                 result = await fn(*args, **kwargs)
+                if isinstance(result, Response):
+                    result.raise_for_status()
                 if result:
                     return result
+            except HTTPStatusError as e:
+                status_code = e.response.status_code
+                logger.debug(f"HTTP status {status_code} - {e}")
+                if status_code in retry_httpx_status_stop:
+                    message = f"HTTP status {status_code} is in retry_httpx_status_stop"
+                    raise RetryHTTPException(message) from e
             except retry_ignore_exc_types as e:
                 last_exception = e
+
             logger.debug(
-                f"Retrying {fn} - in {retry_delay} seconds "
-                f"- attempt {attempt + 1}/{retry_max}"
+                f"Retrying {fn_name} - in {retry_backoff_interval:.1f}s "
+                f"({monotonic() - start:.1f}s / {retry_timeout:.1f}s)"
             )
-            await asyncio.sleep(retry_delay)
+            attempts += 1
+
+            if retry_attempts is not None and attempts >= retry_attempts:
+                raise RetryException(f"Retry attempts exceeded: {retry_attempts}")
+
+            await asyncio.sleep(retry_backoff_interval)
+
         if last_exception is not None:
             raise type(last_exception) from last_exception
         return result