setup: Perform package operations immediately on trigger

- Operations triggered by FreedomBox service itself such 'apt-get update' and
'apt-get install' don't cause the package operations (post-install and
post-update) to get triggered. This is due to recent implementation of a check
with the FREEDOMBOX_INVOKED environment variable. So, it fairly safe to attempt
these operations immediately as they would have been invoked from outside.

- In one case, when unattended-upgrades is triggered it could lead to
post-install trigger getting triggered too quickly. But this only leads the
operation detecting that apt is busy and performing the long wait immediately
after.

- In case of distribution upgrade, this could mean simpler reasoning and less
wait time.

Tests:

- When a package is installed, post-dpkg operations are triggered and completed
immediately. However, another apt process immediately takes lock, this results
in a waiting period.

- When a 'apt update' is run, update operations are triggered and completed
immediately.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/setup.py

@@ -469,12 +469,6 @@ class ForceUpgrader():
 
         """
         for _ in range(self.UPGRADE_ATTEMPTS):
-            logger.info('Waiting for %s seconds before attempting upgrade',
-                        self.UPGRADE_ATTEMPT_WAIT_SECONDS)
-            if self._wait_event.wait(self.UPGRADE_ATTEMPT_WAIT_SECONDS):
-                logger.info('Stopping upgrade attempts due to shutdown')
-                return
-
             try:
                 logger.info('Attempting to perform upgrade')
                 self._attempt_upgrade()
@@ -489,6 +483,12 @@ class ForceUpgrader():
                 # Assume all other errors are temporary
                 logger.exception('Unknown exception: %s', exception)
 
+            logger.info('Waiting for %s seconds before attempting upgrade',
+                        self.UPGRADE_ATTEMPT_WAIT_SECONDS)
+            if self._wait_event.wait(self.UPGRADE_ATTEMPT_WAIT_SECONDS):
+                logger.info('Stopping upgrade attempts due to shutdown')
+                return
+
         logger.info('Giving up on upgrade after too many retries')
 
     def shutdown(self):
@@ -748,14 +748,6 @@ class DpkgHandler:
         This method is guaranteed to not to run more than once simultaneously.
         """
         for _ in range(self.HANDLE_ATTEMPTS):
-            logger.info(
-                'Waiting for %s seconds before attempting post-dpkg '
-                'operations', self.HANDLE_ATTEMPT_WAIT_SECONDS)
-            if self._wait_event.wait(self.HANDLE_ATTEMPT_WAIT_SECONDS):
-                logger.info(
-                    'Stopping post-dpkg operation attempts due to shutdown')
-                return
-
             try:
                 logger.info('Attempting to perform post-dpkg operations')
                 self._attempt_post_invoke()
@@ -771,6 +763,14 @@ class DpkgHandler:
                 # Assume all other errors are temporary
                 logger.exception('Unknown exception: %s', exception)
 
+            logger.info(
+                'Waiting for %s seconds before attempting post-dpkg '
+                'operations', self.HANDLE_ATTEMPT_WAIT_SECONDS)
+            if self._wait_event.wait(self.HANDLE_ATTEMPT_WAIT_SECONDS):
+                logger.info(
+                    'Stopping post-dpkg operation attempts due to shutdown')
+                return
+
         logger.info('Giving up on post-dpkg operations after too many retries')
 
     def _attempt_post_invoke(self) -> None: