From 59efce8bc81fc7800d2cb6ba696028832063a6e0 Mon Sep 17 00:00:00 2001
From: Alan Baghumian <alan.baghumian@canonical.com>
Date: Mon, 6 Nov 2023 16:06:45 -0800
Subject: [PATCH] Restore original paste files if glance-common re-installation
 does not restore them.

Implemented a unit test function for the above
scenario.

Call apt_update from upgrade_charm().

Closes-Bug: #2042792

Change-Id: I57c5fa293b421483b0879f24ddac260e47c7cbef
---
 hooks/glance_relations.py       |  1 +
 hooks/glance_utils.py           | 11 ++++++++++-
 unit_tests/test_glance_utils.py | 30 ++++++++++++++++++++++++++----
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/hooks/glance_relations.py b/hooks/glance_relations.py
index 97a71d02..5659b1c7 100755
--- a/hooks/glance_relations.py
+++ b/hooks/glance_relations.py
@@ -487,6 +487,7 @@ def cluster_changed():
 @harden()
 def upgrade_charm():
     resolve_CONFIGS()
+    apt_update()
     apt_install(filter_installed_packages(determine_packages()), fatal=True)
     packages_removed = remove_old_packages()
     backup_deprecated_configurations()
diff --git a/hooks/glance_utils.py b/hooks/glance_utils.py
index d1f5a02d..90e755a7 100644
--- a/hooks/glance_utils.py
+++ b/hooks/glance_utils.py
@@ -636,7 +636,7 @@ def reinstall_paste_ini(force_reinstall=False):
         for paste_file in [GLANCE_REGISTRY_PASTE,
                            GLANCE_API_PASTE]:
             if os.path.exists(paste_file):
-                os.remove(paste_file)
+                os.replace(paste_file, f'{paste_file}.charm.upgrade')
         # glance-registry is deprecated at queens but still
         # installed.
         if cmp_release < 'rocky':
@@ -647,6 +647,15 @@ def reinstall_paste_ini(force_reinstall=False):
         apt_install(packages=pkg_list,
                     options=REINSTALL_OPTIONS,
                     fatal=True)
+        # LP: #2042792 Restore original paste files
+        for paste_file in [GLANCE_REGISTRY_PASTE,
+                           GLANCE_API_PASTE]:
+            if not os.path.exists(paste_file):
+                if os.path.exists(f'{paste_file}.charm.upgrade'):
+                    os.replace(f'{paste_file}.charm.upgrade', paste_file)
+            else:
+                if os.path.exists(f'{paste_file}.charm.upgrade'):
+                    os.remove(f'{paste_file}.charm.upgrade')
         db.set(PASTE_INI_MARKER, True)
         db.flush()
 
diff --git a/unit_tests/test_glance_utils.py b/unit_tests/test_glance_utils.py
index bcacc0af..ee2de9ee 100644
--- a/unit_tests/test_glance_utils.py
+++ b/unit_tests/test_glance_utils.py
@@ -369,10 +369,6 @@ class TestGlanceUtils(CharmTestCase):
             call(utils.GLANCE_REGISTRY_PASTE),
             call(utils.GLANCE_API_PASTE),
         ])
-        _os.remove.assert_has_calls([
-            call(utils.GLANCE_REGISTRY_PASTE),
-            call(utils.GLANCE_API_PASTE),
-        ])
         self.assertTrue(test_kv.get(utils.PASTE_INI_MARKER))
         self.assertTrue(test_kv.flushed)
 
@@ -439,6 +435,32 @@ class TestGlanceUtils(CharmTestCase):
         utils.reinstall_paste_ini()
         self.assertTrue(self.apt_install.called)
 
+    @patch.object(utils, 'os_release')
+    @patch.object(utils, 'os')
+    @patch.object(utils, 'kv')
+    def test_reinstall_paste_ini_rocky_restore(self, kv, _os, mock_os_release):
+        """Ensure that paste.ini files are restored"""
+        mock_os_release.return_value = 'rocky'
+        _os.path.exists.return_value = True
+        test_kv = SimpleKV()
+        test_kv.set(utils.PASTE_INI_MARKER, False)
+        kv.return_value = test_kv
+
+        self.apt_install.reset_mock()
+        utils.reinstall_paste_ini()
+
+        self.apt_install.assert_called_with(
+            packages=['glance-common'],
+            options=utils.REINSTALL_OPTIONS,
+            fatal=True
+        )
+        reg_paste_backup = f'{utils.GLANCE_REGISTRY_PASTE}.charm.upgrade'
+        api_paste_backup = f'{utils.GLANCE_API_PASTE}.charm.upgrade'
+        _os.remove.assert_has_calls([
+            call(reg_paste_backup),
+            call(api_paste_backup),
+        ])
+
     def _test_is_api_ready(self, tgt):
         fake_config = MagicMock()
         with patch.object(utils, 'incomplete_relation_data') as ird: