settings: Allow customizing HOME_NOT_LOGGED_IN.

This can be useful if one wants a third-party authentication system to
apply first.

zproject/computed_settings.py

@@ -38,6 +38,7 @@ from .configured_settings import (
     EXTERNAL_URI_SCHEME,
     EXTRA_INSTALLED_APPS,
     GOOGLE_OAUTH2_CLIENT_ID,
+    HOME_NOT_LOGGED_IN,
     INVITATION_LINK_VALIDITY_DAYS,
     IS_DEV_DROPLET,
     LOCAL_UPLOADS_DIR,
@@ -1038,18 +1039,14 @@ ONLY_LDAP = AUTHENTICATION_BACKENDS == ("zproject.backends.ZulipLDAPAuthBackend"
 USING_APACHE_SSO = "zproject.backends.ZulipRemoteUserBackend" in AUTHENTICATION_BACKENDS
 ONLY_SSO = AUTHENTICATION_BACKENDS == ("zproject.backends.ZulipRemoteUserBackend",)
 
-if ONLY_SSO:
-    HOME_NOT_LOGGED_IN = "/accounts/login/sso/"
-else:
-    HOME_NOT_LOGGED_IN = "/login/"
+if HOME_NOT_LOGGED_IN is None:
+    if ONLY_SSO:
+        HOME_NOT_LOGGED_IN = "/accounts/login/sso/"
+    else:
+        HOME_NOT_LOGGED_IN = "/login/"
 
 AUTHENTICATION_BACKENDS += ("zproject.backends.ZulipDummyBackend",)
 
-# Redirect to /devlogin/ by default in dev mode
-if DEVELOPMENT:
-    HOME_NOT_LOGGED_IN = "/devlogin/"
-    LOGIN_URL = "/devlogin/"
-
 POPULATE_PROFILE_VIA_LDAP = bool(AUTH_LDAP_SERVER_URI)
 
 if POPULATE_PROFILE_VIA_LDAP and not USING_LDAP:

zproject/default_settings.py

@@ -106,6 +106,7 @@ SOCIAL_AUTH_SYNC_CUSTOM_ATTRS_DICT: Dict[str, Dict[str, Dict[str, str]]] = {}
 
 # Other auth
 SSO_APPEND_DOMAIN: Optional[str] = None
+HOME_NOT_LOGGED_IN: Optional[str] = None
 
 VIDEO_ZOOM_CLIENT_ID = get_secret("video_zoom_client_id", development_only=True)
 VIDEO_ZOOM_CLIENT_SECRET = get_secret("video_zoom_client_secret")

zproject/dev_settings.py

@@ -77,6 +77,10 @@ OPEN_REALM_CREATION = True
 WEB_PUBLIC_STREAMS_ENABLED = True
 INVITES_MIN_USER_AGE_DAYS = 0
 
+# Redirect to /devlogin/ by default in dev mode
+HOME_NOT_LOGGED_IN = "/devlogin/"
+LOGIN_URL = "/devlogin/"
+
 # For development convenience, configure the ToS/Privacy Policies
 POLICIES_DIRECTORY = "corporate/policies"
 TERMS_OF_SERVICE_VERSION = "1.0"