general: add options to automatically retry requests (#49764)

passerelle/base/models.py

@@ -142,6 +142,12 @@ class BaseResource(models.Model):
     manager_form_base_class = GenericConnectorForm
     hide_description_fields = []
 
+    # self.requests retry behaviour
+    retry_count = 0
+    retry_on_status = [429, 500, 502, 503, 504]
+    retry_on_methods = ['HEAD', 'GET', 'POST', 'PUT', 'DELETE', 'OPTIONS', 'TRACE']
+    retry_backoff_factor = 0.5
+
     # permission descriptions
     _can_access_description = _('Access is limited to the following API users:')
 

passerelle/utils/__init__.py

@@ -24,9 +24,11 @@ import warnings
 
 from requests import Session as RequestSession, Response as RequestResponse
 from requests.adapters import HTTPAdapter
+from requests.packages.urllib3.util.retry import Retry
 from requests.structures import CaseInsensitiveDict
 from urllib3.exceptions import InsecureRequestWarning
 
+
 from django.conf import settings
 from django.core.cache import cache
 from django.core.exceptions import PermissionDenied
@@ -243,7 +245,17 @@ class Request(RequestSession):
         self.resource = kwargs.pop('resource', None)
         super(Request, self).__init__(*args, **kwargs)
         if self.resource:
-            adapter = Request.ADAPTER_REGISTRY.setdefault(type(self.resource), HTTPAdapter())
+            if getattr(self.resource, 'retry_count', 0):
+                retry_strategy = Retry(
+                    total=self.resource.retry_count,
+                    backoff_factor=self.resource.retry_backoff_factor,
+                    status_forcelist=self.resource.retry_on_status,
+                    method_whitelist=self.resource.retry_on_methods
+                )
+            else:
+                retry_strategy = 0
+            adapter = Request.ADAPTER_REGISTRY.setdefault(type(self.resource),
+                    HTTPAdapter(max_retries=retry_strategy))
             self.mount('https://', adapter)
             self.mount('http://', adapter)