Add: exceptions constant for api access retries

We have seen 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 with the already existing retry
functionality 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.

The constant is in a new constants file to avoid circular dependencies
from code that is called from the cli module back to the cli module
itself.

TODO:

1) We should refactor these accesses afterwards when the high prio for
   production 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.

2) also mode the existing constans from cli.py into wht constants file,
   also to avoid circular dependencies.

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

@@ -9,7 +9,6 @@
 from pathlib import Path
 from typing import Sequence
 
-import httpx
 import shtab
 import stamina
 from pontos.nvd import now
@@ -29,6 +28,7 @@
     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 +212,7 @@ 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 +255,7 @@ 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,
                 ):