From ac2d55d272aa7690236fefccce6b6f400cc0ba3d Mon Sep 17 00:00:00 2001
From: Milan <milan@berri.ai>
Date: Tue, 28 Apr 2026 14:35:07 +0300
Subject: [PATCH] fix(proxy): surface callback env vars in config API

Made-with: Cursor
---
 litellm/proxy/common_utils/callback_utils.py  |  3 +-
 .../proxy/common_utils/test_callback_utils.py | 85 +++++++++++++++++++
 2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/litellm/proxy/common_utils/callback_utils.py b/litellm/proxy/common_utils/callback_utils.py
index 7ddd722a80e..25fbc0d4461 100644
--- a/litellm/proxy/common_utils/callback_utils.py
+++ b/litellm/proxy/common_utils/callback_utils.py
@@ -1,3 +1,4 @@
+import os
 from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Literal, Optional
 
 import litellm
@@ -528,7 +529,7 @@ def process_callback(
     for _var in env_vars:
         env_variable = environment_variables.get(_var, None)
         if env_variable is None:
-            env_vars_dict[_var] = None
+            env_vars_dict[_var] = os.getenv(_var)
         else:
             env_vars_dict[_var] = env_variable
 
diff --git a/tests/test_litellm/proxy/common_utils/test_callback_utils.py b/tests/test_litellm/proxy/common_utils/test_callback_utils.py
index c6132194c74..a856a19dcad 100644
--- a/tests/test_litellm/proxy/common_utils/test_callback_utils.py
+++ b/tests/test_litellm/proxy/common_utils/test_callback_utils.py
@@ -76,6 +76,91 @@ def test_process_callback_with_no_required_env_vars(mock_get_env_vars):
     assert result["variables"] == {}
 
 
+@patch(
+    "litellm.proxy.common_utils.callback_utils.CustomLogger.get_callback_env_vars",
+    return_value=["GENERIC_LOGGER_ENDPOINT", "GENERIC_LOGGER_HEADERS"],
+)
+def test_process_callback_generic_api_falls_back_to_os_env(
+    mock_get_env_vars, monkeypatch
+):
+    monkeypatch.setenv("GENERIC_LOGGER_ENDPOINT", "https://callback.example.com")
+    monkeypatch.setenv("GENERIC_LOGGER_HEADERS", "Authorization=Bearer token")
+
+    result = process_callback(
+        _callback="generic_api",
+        callback_type="success",
+        environment_variables={},
+    )
+
+    assert result["variables"] == {
+        "GENERIC_LOGGER_ENDPOINT": "https://callback.example.com",
+        "GENERIC_LOGGER_HEADERS": "Authorization=Bearer token",
+    }
+
+
+@patch(
+    "litellm.proxy.common_utils.callback_utils.CustomLogger.get_callback_env_vars",
+    return_value=["GENERIC_LOGGER_ENDPOINT", "GENERIC_LOGGER_HEADERS"],
+)
+def test_process_callback_custom_callback_api_falls_back_to_os_env(
+    mock_get_env_vars, monkeypatch
+):
+    monkeypatch.setenv("GENERIC_LOGGER_ENDPOINT", "https://callback.example.com")
+    monkeypatch.setenv("GENERIC_LOGGER_HEADERS", "Authorization=Bearer token")
+
+    result = process_callback(
+        _callback="custom_callback_api",
+        callback_type="success",
+        environment_variables={},
+    )
+
+    assert result["variables"] == {
+        "GENERIC_LOGGER_ENDPOINT": "https://callback.example.com",
+        "GENERIC_LOGGER_HEADERS": "Authorization=Bearer token",
+    }
+
+
+@patch(
+    "litellm.proxy.common_utils.callback_utils.CustomLogger.get_callback_env_vars",
+    return_value=["GENERIC_LOGGER_ENDPOINT", "GENERIC_LOGGER_HEADERS"],
+)
+def test_process_callback_config_value_wins_over_os_env(mock_get_env_vars, monkeypatch):
+    monkeypatch.setenv("GENERIC_LOGGER_ENDPOINT", "https://env.example.com")
+    monkeypatch.setenv("GENERIC_LOGGER_HEADERS", "Authorization=Bearer env")
+
+    result = process_callback(
+        _callback="generic_api",
+        callback_type="success",
+        environment_variables={
+            "GENERIC_LOGGER_ENDPOINT": "https://config.example.com",
+            "GENERIC_LOGGER_HEADERS": "Authorization=Bearer config",
+        },
+    )
+
+    assert result["variables"] == {
+        "GENERIC_LOGGER_ENDPOINT": "https://config.example.com",
+        "GENERIC_LOGGER_HEADERS": "Authorization=Bearer config",
+    }
+
+
+@patch(
+    "litellm.proxy.common_utils.callback_utils.CustomLogger.get_callback_env_vars",
+    return_value=["LANGFUSE_PUBLIC_KEY"],
+)
+def test_process_callback_falls_back_to_os_env_for_registered_callback_vars(
+    mock_get_env_vars, monkeypatch
+):
+    monkeypatch.setenv("LANGFUSE_PUBLIC_KEY", "pk-env")
+
+    result = process_callback(
+        _callback="langfuse",
+        callback_type="success",
+        environment_variables={},
+    )
+
+    assert result["variables"] == {"LANGFUSE_PUBLIC_KEY": "pk-env"}
+
+
 def test_normalize_callback_names_none_returns_empty_list():
     assert normalize_callback_names(None) == []
     assert normalize_callback_names([]) == []