feat: introduce retry mechanism for session

sw360/sw360_api.py

@@ -12,6 +12,8 @@
 from typing import Any, Dict, Optional
 
 import requests
+from requests.adapters import HTTPAdapter
+from urllib3.util.retry import Retry
 
 from .attachments import AttachmentsMixin
 from .clearing import ClearingMixin
@@ -23,6 +25,17 @@
 from .vendor import VendorMixin
 from .vulnerabilities import VulnerabilitiesMixin
 
+# Retry mechanism for rate limiting
+adapter = HTTPAdapter(max_retries=Retry(
+    total=5,
+    status_forcelist=[429, 500, 502, 503, 504],
+    respect_retry_after_header=True,
+    backoff_factor=30,
+    allowed_methods=["HEAD", "GET", "OPTIONS", "POST", "PUT", "PATCH"]
+))
+session = requests.Session()
+session.mount("http://", adapter)
+session.mount("https://", adapter)
 
 class SW360(
     AttachmentsMixin,
@@ -75,7 +88,7 @@ def login_api(self, token: str = "") -> bool:
         :raises SW360Error: if the login fails
         """
         if not self.force_no_session:
-            self.session = requests.Session()
+            self.session = session
             self.session.headers = self.api_headers.copy()  # type: ignore
 
         url = self.url + "resource/api/"

tests/test_sw360_base.py

@@ -298,7 +298,24 @@ def test_api_get_raw_error_string(self) -> None:
         else:
             self.assertEqual(404, context.exception.response.status_code)
             self.assertEqual("Error-String", context.exception.response.text)
+
+    @responses.activate
+    def test_login_server_not_responding(self) -> None:
+        lib = SW360(self.MYURL, self.MYTOKEN, False)
 
+        responses.add(
+            responses.GET,
+            url=self.MYURL + "resource/api/",
+            body = '{"error": "Internal Server Error", "message": "An unexpected error occurred on the server."}',
+            status=500,
+            content_type="application/json",
+            adding_headers={"Authorization": "Token " + self.MYTOKEN},
+        )
+
+        with self.assertRaises(SW360Error) as context:
+            lib.login_api()
+
+        self.assertEqual(self.ERROR_MSG_NO_LOGIN, context.exception.message)
 
 if __name__ == "__main__":
     unittest.main()