Fix fetch_access_token_for_cluster in EKS hook

providers/src/airflow/providers/amazon/aws/hooks/eks.py

@@ -612,9 +612,8 @@ def generate_config_file(
     def fetch_access_token_for_cluster(self, eks_cluster_name: str) -> str:
         session = self.get_session()
         service_id = self.conn.meta.service_model.service_id
-        sts_url = (
-            f"https://sts.{session.region_name}.amazonaws.com/?Action=GetCallerIdentity&Version=2011-06-15"
-        )
+        sts_client = session.client("sts")
+        sts_url = f"{sts_client.meta.endpoint_url}/?Action=GetCallerIdentity&Version=2011-06-15"
 
         signer = RequestSigner(
             service_id=service_id,

providers/tests/amazon/aws/hooks/test_eks.py

@@ -22,6 +22,7 @@
 from pathlib import Path
 from typing import TYPE_CHECKING
 from unittest import mock
+from unittest.mock import Mock
 from urllib.parse import urlsplit
 
 import pytest
@@ -1288,6 +1289,9 @@ def test_generate_config_file(self, mock_conn, aws_conn_id, region_name, expecte
     def test_fetch_access_token_for_cluster(self, mock_get_session, mock_conn, mock_signer):
         mock_signer.return_value.generate_presigned_url.return_value = "http://example.com"
         mock_get_session.return_value.region_name = "us-east-1"
+        client = Mock()
+        client.meta.endpoint_url = "https://sts.us-east-1.amazonaws.com"
+        mock_get_session.return_value.client.return_value = client
         hook = EksHook()
         token = hook.fetch_access_token_for_cluster(eks_cluster_name="test-cluster")
         mock_signer.assert_called_once_with(