From ff5c274048df12e5ed769f80c89d0408d2410f6b Mon Sep 17 00:00:00 2001
From: jeremystretch <jstretch@ns1.com>
Date: Tue, 26 Oct 2021 16:45:53 -0400
Subject: [PATCH] Ensure bootstrapping of config on start

---
 netbox/extras/models/models.py   |  7 +++++++
 netbox/extras/signals.py         |  4 +---
 netbox/netbox/config/__init__.py | 18 ++++++++++++++++--
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/netbox/extras/models/models.py b/netbox/extras/models/models.py
index 4f93b19ce..d4d6d648e 100644
--- a/netbox/extras/models/models.py
+++ b/netbox/extras/models/models.py
@@ -560,6 +560,13 @@ class ConfigRevision(models.Model):
             return self.data[item]
         return super().__getattribute__(item)
 
+    def cache(self):
+        """
+        Cache the configuration data.
+        """
+        cache.set('config', self.data, None)
+        cache.set('config_version', self.pk, None)
+
     @admin.display(boolean=True)
     def is_active(self):
         return cache.get('config_version') == self.pk
diff --git a/netbox/extras/signals.py b/netbox/extras/signals.py
index 01fd30f15..ce1dead8f 100644
--- a/netbox/extras/signals.py
+++ b/netbox/extras/signals.py
@@ -2,7 +2,6 @@ import logging
 
 from django.conf import settings
 from django.contrib.contenttypes.models import ContentType
-from django.core.cache import cache
 from django.db.models.signals import m2m_changed, post_save, pre_delete
 from django.dispatch import receiver, Signal
 from django_prometheus.models import model_deletes, model_inserts, model_updates
@@ -173,5 +172,4 @@ def update_config(sender, instance, **kwargs):
     """
     Update the cached NetBox configuration when a new ConfigRevision is created.
     """
-    cache.set('config', instance.data, None)
-    cache.set('config_version', instance.pk, None)
+    instance.cache()
diff --git a/netbox/netbox/config/__init__.py b/netbox/netbox/config/__init__.py
index bd70e2e41..49d4cf4fe 100644
--- a/netbox/netbox/config/__init__.py
+++ b/netbox/netbox/config/__init__.py
@@ -43,8 +43,9 @@ class Config:
     must be re-instantiated each time it's necessary to check for updates to the cached config.
     """
     def __init__(self):
-        self.config = cache.get('config') or {}
-        self.version = cache.get('config_version')
+        self._populate_from_cache()
+        if not self.config or not self.version:
+            self._populate_from_db()
         self.defaults = {param.name: param.default for param in PARAMS}
         logger.debug("Loaded configuration data from cache")
 
@@ -64,6 +65,19 @@ class Config:
 
         raise AttributeError(f"Invalid configuration parameter: {item}")
 
+    def _populate_from_cache(self):
+        """Populate config data from Redis cache"""
+        self.config = cache.get('config') or {}
+        self.version = cache.get('config_version')
+
+    def _populate_from_db(self):
+        """Cache data from latest ConfigRevision, then populate from cache"""
+        from extras.models import ConfigRevision
+        revision = ConfigRevision.objects.last()
+        revision.cache()
+        logger.debug("Filled cache with data from latest ConfigRevision")
+        self._populate_from_cache()
+
 
 class ConfigItem:
     """