Move _parse_retry_after to exporters/utils.py as standalone parse_retry_after function

Co-authored-by: nikhilNava <211831449+nikhilNava@users.noreply.github.com>

Author: Copilot

libraries/microsoft-agents-a365-observability-core/microsoft_agents_a365/observability/core/exporters/agent365_exporter.py

@@ -23,6 +23,7 @@
     hex_span_id,
     hex_trace_id,
     kind_name,
+    parse_retry_after,
     partition_by_identity,
     status_name,
     truncate_span,
@@ -162,21 +163,6 @@ def _truncate_text(text: str, max_length: int) -> str:
             return text[:max_length] + "..."
         return text
 
-    @staticmethod
-    def _parse_retry_after(resp: requests.Response) -> float | None:
-        """Parse the Retry-After header from a response.
-
-        Returns:
-            The number of seconds to wait, or None if the header is absent or invalid.
-        """
-        retry_after = resp.headers.get("Retry-After")
-        if retry_after is None:
-            return None
-        try:
-            return float(retry_after)
-        except (ValueError, TypeError):
-            return None
-
     def _post_with_retries(self, url: str, body: str, headers: dict[str, str]) -> bool:
         for attempt in range(DEFAULT_MAX_RETRIES + 1):
             try:
@@ -209,7 +195,7 @@ def _post_with_retries(self, url: str, body: str, headers: dict[str, str]) -> bo
                 # Retry transient
                 if resp.status_code in (408, 429) or 500 <= resp.status_code < 600:
                     # Respect Retry-After header for 429 responses
-                    retry_after = self._parse_retry_after(resp)
+                    retry_after = parse_retry_after(resp.headers)
                     if attempt < DEFAULT_MAX_RETRIES:
                         if retry_after is not None:
                             time.sleep(min(retry_after, 60.0))

libraries/microsoft-agents-a365-observability-core/microsoft_agents_a365/observability/core/exporters/utils.py

@@ -1,6 +1,8 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 
+from __future__ import annotations
+
 import json
 import logging
 import os
@@ -230,6 +232,31 @@ def build_export_url(
     return f"https://{endpoint}{endpoint_path}?api-version=1"
 
 
+def parse_retry_after(headers: dict[str, str]) -> float | None:
+    """Parse the ``Retry-After`` header value.
+
+    Only numeric (seconds) values are supported.  HTTP-date values
+    (e.g. ``Wed, 21 Oct 2025 07:28:00 GMT``) are intentionally ignored
+    and treated as absent, falling back to exponential backoff.
+
+    Args:
+        headers: Response headers mapping.
+
+    Returns:
+        The number of seconds to wait, or ``None`` if the header is
+        absent, non-numeric, or otherwise invalid.
+    """
+    retry_after = headers.get("Retry-After")
+    if retry_after is None:
+        return None
+    try:
+        return float(retry_after)
+    except (ValueError, TypeError):
+        # Intentionally ignore HTTP-date formatted Retry-After values;
+        # callers should fall back to exponential backoff.
+        return None
+
+
 def is_agent365_exporter_enabled() -> bool:
     """Check if Agent 365 exporter is enabled."""
     # Check environment variable