firstboot: Fix caching issue in collecting first_boot steps

- Created a django singal to indicate that a setup happened

- Clearing the cached list of firstboot_steps each time the above signal is sent

Closes #1193.

Signed-off-by: Joseph Nuthalapati <njoseph@thoughtworks.com>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/modules/first_boot/__init__.py

@@ -14,15 +14,16 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
-
 """
 Plinth module for first boot wizard
 """
 
-from django.urls import reverse
 import operator
 
+from django.urls import reverse
+
 from plinth import module_loader
+from plinth.signals import post_setup
 
 version = 1
 
@@ -47,6 +48,17 @@ _all_first_boot_steps = None
 _is_completed = None
 
 
+def init():
+    """Initialize the first boot module."""
+    post_setup.connect(_clear_first_boot_steps)
+
+
+def _clear_first_boot_steps(sender, module_name, **kwargs):
+    """Flush the cache of first boot steps so it is recreated."""
+    global _all_first_boot_steps
+    _all_first_boot_steps = None
+
+
 def is_firstboot_url(path):
     """Return whether a path is a firstboot step URL.
 

plinth/modules/pagekite/views.py

@@ -141,10 +141,9 @@ class FirstBootView(FormView):
     form_class = FirstBootForm
 
     def get(self, request, *args, **kwargs):
-        """Skip if this first boot step if it is not relavent."""
+        """Skip this first boot step if it is not relevant."""
         if not cfg.danube_edition:
-            first_boot.mark_step_done('pagekite_firstboot')
-            return HttpResponseRedirect(reverse(first_boot.next_step()))
+            return first_boot_skip(request)
 
         return super().get(request, *args, **kwargs)
 

plinth/setup.py

@@ -18,14 +18,17 @@
 Plinth module with utilites for performing application setup operations.
 """
 
-import apt
 import logging
 import threading
 import time
 
+import apt
+
+import plinth
+from plinth.signals import post_setup
+
 from . import package
 from .errors import PackageNotInstalledError
-import plinth
 
 logger = logging.getLogger(__name__)
 
@@ -91,6 +94,8 @@ class Helper(object):
             raise exception
         else:
             self.set_setup_version(self.module.version)
+            post_setup.send_robust(sender=self.__class__,
+                                   module_name=self.module_name)
         finally:
             self.is_finished = True
             self.current_operation = None

plinth/signals.py

@@ -25,6 +25,7 @@ from django.dispatch import Signal
 service_enabled = Signal(providing_args=['service_id', 'enabled'])
 pre_module_loading = Signal()
 post_module_loading = Signal()
+post_setup = Signal(providing_args=['module_name'])
 pre_hostname_change = Signal(providing_args=['old_hostname', 'new_hostname'])
 post_hostname_change = Signal(providing_args=['old_hostname', 'new_hostname'])
 domainname_change = Signal(providing_args=['old_domainname', 'new_domainname'])