Add a exceptions constant for api access retries

We have run in problems with the application when the nvd API responds
properly http wise, but delivers json that cannot be decoded properly.

To keep retrying these API calls until they succeed, which currently
happens after ~ 1-5 tries, we need to use a tuple with the already used
http error and also JSONDecodeError.

As this happens multiple times, we use a constant that can be used in
multiple places.

We should refactor these accesses afterwards when the high prio fix is
done, in order to have this functionality reusable in one place, because
having the basically same stamina call in so many places calls for
improvement.

Author: henning

greenbone/scap/constants.py

@@ -0,0 +1,9 @@
+# SPDX-FileCopyrightText: 2025 Greenbone AG
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+from json import JSONDecodeError
+
+from httpx import HTTPError
+
+# Exceptions on API access to catch in order to retry these calls
+STAMINA_API_RETRY_EXCEPTIONS = (JSONDecodeError, HTTPError)

greenbone/scap/cpe/cli/download.py

@@ -29,6 +29,7 @@
     CLIError,
     CLIRunner,
 )
+from greenbone.scap.constants import STAMINA_API_RETRY_EXCEPTIONS
 from greenbone.scap.cpe.manager import CPEManager
 from greenbone.scap.db import PostgresDatabase
 from greenbone.scap.timer import Timer
@@ -206,7 +207,7 @@ async def _producer(
             with Timer() as download_timer:
                 count = 0
                 async for attempt in stamina.retry_context(
-                    on=httpx.HTTPError,
+                    on=STAMINA_API_RETRY_EXCEPTIONS,
                     attempts=retry_attempts,
                     timeout=None,
                 ):
@@ -250,7 +251,7 @@ async def download(
         last_modified_end_date: datetime | None,
     ) -> None:
         async for attempt in stamina.retry_context(
-            on=httpx.HTTPError,
+            on=STAMINA_API_RETRY_EXCEPTIONS,
             attempts=retry_attempts,
             timeout=None,
         ):

greenbone/scap/cve/cli/download.py

@@ -6,12 +6,14 @@
 import os
 from argparse import ArgumentParser, Namespace
 from datetime import datetime
+from json import JSONDecodeError
 from pathlib import Path
 from typing import Sequence
 
 import httpx
 import shtab
 import stamina
+from httpx import HTTPError
 from pontos.nvd import now
 from pontos.nvd.api import NVDResults
 from pontos.nvd.cve import CVEApi
@@ -29,6 +31,7 @@
     CLIError,
     CLIRunner,
 )
+from greenbone.scap.constants import STAMINA_API_RETRY_EXCEPTIONS
 from greenbone.scap.cve.manager import CVEManager
 from greenbone.scap.db import PostgresDatabase
 from greenbone.scap.timer import Timer
@@ -212,7 +215,7 @@ async def _producer(
             with Timer() as download_timer:
                 count = 0
                 async for attempt in stamina.retry_context(
-                    on=httpx.HTTPError,
+                    on=STAMINA_API_RETRY_EXCEPTIONS,
                     attempts=retry_attempts,
                     timeout=None,
                 ):
@@ -255,7 +258,7 @@ async def download(
         last_modified_end_date: datetime | None,
     ) -> None:
         async for attempt in stamina.retry_context(
-            on=httpx.HTTPError,
+            on=STAMINA_API_RETRY_EXCEPTIONS,
             attempts=retry_attempts,
             timeout=None,
         ):

greenbone/scap/generic_cli/producer/nvd_api.py

@@ -17,6 +17,7 @@
     DEFAULT_RETRIES,
     DEFAULT_VERBOSITY,
 )
+from ...constants import STAMINA_API_RETRY_EXCEPTIONS
 
 from ...timer import Timer
 from .base import BaseScapProducer
@@ -222,7 +223,7 @@ async def fetch_initial_data(
             The number of expected items.
         """
         async for attempt in stamina.retry_context(
-            on=httpx.HTTPError,
+            on=STAMINA_API_RETRY_EXCEPTIONS,
             attempts=self._retry_attempts,
             timeout=None,
         ):
@@ -275,7 +276,7 @@ async def run_loop(
             with Timer() as download_timer:
                 count = 0
                 async for attempt in stamina.retry_context(
-                    on=httpx.HTTPError,
+                    on=STAMINA_API_RETRY_EXCEPTIONS,
                     attempts=self._additional_retry_attempts,
                     timeout=None,
                 ):