Validate settings before running Pulp instance

CHANGES/1550.bugfix

@@ -0,0 +1,2 @@
+Pulp Container specific settings are now properly validated during the deployment checks of a Pulp
+instance.

pulp_container/app/__init__.py

@@ -11,3 +11,4 @@ class PulpContainerPluginAppConfig(PulpPluginAppConfig):
 
     def ready(self):
         super().ready()
+        from . import checks

pulp_container/app/checks.py

@@ -0,0 +1,46 @@
+from django.conf import settings
+from django.core.checks import Error as CheckError, register
+
+
+@register(deploy=True)
+def container_settings_check(app_configs, **kwargs):
+    errors = []
+
+    # Other checks only apply if token auth is enabled
+    if str(getattr(settings, "TOKEN_AUTH_DISABLED", False)).lower() == "true":
+        return errors
+
+    if getattr(settings, "TOKEN_SERVER", None) is None:
+        errors.append(
+            CheckError(
+                "TOKEN_SERVER is a required setting that has to be configured when token"
+                " authentification is enabled",
+                id="pulp_container.E001",
+            ),
+        )
+    if getattr(settings, "TOKEN_SIGNATURE_ALGORITHM", None) is None:
+        errors.append(
+            CheckError(
+                "TOKEN_SIGNATURE_ALGORITHM is a required setting that has to be configured when"
+                " token authentification is enabled",
+                id="pulp_container.E001",
+            )
+        )
+    if getattr(settings, "PUBLIC_KEY_PATH", None) is None:
+        errors.append(
+            CheckError(
+                "PUBLIC_KEY_PATH is a required setting that has to be configured when token"
+                " authentification is enabled",
+                id="pulp_container.E001",
+            )
+        )
+    if getattr(settings, "PRIVATE_KEY_PATH", None) is None:
+        errors.append(
+            CheckError(
+                "PRIVATE_KEY_PATH is a required setting that has to be configured when token"
+                " authentification is enabled",
+                id="pulp_container.E001",
+            )
+        )
+
+    return errors