initial commit of new machinery to handle redirects for webhook notifications (#13083)

awx/main/notifications/webhook_backend.py

@@ -5,9 +5,6 @@ import json
 import logging
 import requests
 
-from django.utils.encoding import smart_str
-from django.utils.translation import gettext_lazy as _
-
 from awx.main.notifications.base import AWXBaseEmailBackend
 from awx.main.utils import get_awx_http_client_headers
 from awx.main.notifications.custom_notification_base import CustomNotificationBase
@@ -17,6 +14,8 @@ logger = logging.getLogger('awx.main.notifications.webhook_backend')
 
 class WebhookBackend(AWXBaseEmailBackend, CustomNotificationBase):
 
+    MAX_RETRIES = 5
+
     init_parameters = {
         "url": {"label": "Target URL", "type": "string"},
         "http_method": {"label": "HTTP Method", "type": "string", "default": "POST"},
@@ -64,20 +63,67 @@ class WebhookBackend(AWXBaseEmailBackend, CustomNotificationBase):
         if self.http_method.lower() not in ['put', 'post']:
             raise ValueError("HTTP method must be either 'POST' or 'PUT'.")
         chosen_method = getattr(requests, self.http_method.lower(), None)
+
         for m in messages:
+
             auth = None
             if self.username or self.password:
                 auth = (self.username, self.password)
-            r = chosen_method(
-                "{}".format(m.recipients()[0]),
-                auth=auth,
-                data=json.dumps(m.body, ensure_ascii=False).encode('utf-8'),
-                headers=dict(list(get_awx_http_client_headers().items()) + list((self.headers or {}).items())),
-                verify=(not self.disable_ssl_verification),
-            )
-            if r.status_code >= 400:
-                logger.error(smart_str(_("Error sending notification webhook: {}").format(r.status_code)))
+
+            # the constructor for EmailMessage - https://docs.djangoproject.com/en/4.1/_modules/django/core/mail/message will turn an empty dictionary to an empty string
+            # sometimes an empty dict is intentional and we added this conditional to enforce that
+            if not m.body:
+                m.body = {}
+
+            url = str(m.recipients()[0])
+            data = json.dumps(m.body, ensure_ascii=False).encode('utf-8')
+            headers = {**(get_awx_http_client_headers()), **(self.headers or {})}
+
+            err = None
+
+            for retries in range(self.MAX_RETRIES):
+
+                # Sometimes we hit redirect URLs. We must account for this. We still extract the redirect URL from the response headers and try again. Max retires == 5
+                resp = chosen_method(
+                    url=url,
+                    auth=auth,
+                    data=data,
+                    headers=headers,
+                    verify=(not self.disable_ssl_verification),
+                    allow_redirects=False,  # override default behaviour for redirects
+                )
+
+                # either success or error reached if this conditional fires
+                if resp.status_code not in [301, 307]:
+                    break
+
+                # we've hit a redirect. extract the redirect URL out of the first response header and try again
+                logger.warning(
+                    f"Received a {resp.status_code} from {url}, trying to reach redirect url {resp.headers.get('Location', None)}; attempt #{retries+1}"
+                )
+
+                # take the first redirect URL in the response header and try that
+                url = resp.headers.get("Location", None)
+
+                if url is None:
+                    err = f"Webhook notification received redirect to a blank URL from {url}. Response headers={resp.headers}"
+                    break
+            else:
+                # no break condition in the loop encountered; therefore we have hit the maximum number of retries
+                err = f"Webhook notification max number of retries [{self.MAX_RETRIES}] exceeded. Failed to send webhook notification to {url}"
+
+            if resp.status_code >= 400:
+                err = f"Error sending webhook notification: {resp.status_code}"
+
+            # log error message
+            if err:
+                logger.error(err)
                 if not self.fail_silently:
-                    raise Exception(smart_str(_("Error sending notification webhook: {}").format(r.status_code)))
-            sent_messages += 1
+                    raise Exception(err)
+
+            # no errors were encountered therefore we successfully sent off the notification webhook
+            if resp.status_code in range(200, 299):
+                logger.debug(f"Notification webhook successfully sent to {url}. Received {resp.status_code}")
+                sent_messages += 1
+
         return sent_messages