[DPE-6062] Allow --restore-to-time=latest without a backup-id (#683)

* Allow --restore-to-time=latest without a backup-id Signed-off-by: Marcelo Henrique Neppel <[email protected]> * Fix empty list argument Signed-off-by: Marcelo Henrique Neppel <[email protected]> --------- Signed-off-by: Marcelo Henrique Neppel <[email protected]>
canonical · Nov 26, 2024 · 564932c · 564932c
1 parent 79efef2
commit 564932c
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Showing 2 changed files with 62 additions and 5 deletions.
diff --git a/src/backups.py b/src/backups.py
@@ -516,6 +516,8 @@ def _get_nearest_timeline(self, timestamp: str) -> tuple[str, str] | None:
             (stanza, timeline) of the nearest timeline or backup. None, if there are no matches.
         """
         timelines = self._list_backups(show_failed=False) | self._list_timelines()
+        if timestamp == "latest":
+            return max(timelines.items())[1] if len(timelines) > 0 else None
         filtered_timelines = [
             (timeline_key, timeline_object)
             for timeline_key, timeline_object in timelines.items()
@@ -1026,6 +1028,17 @@ def _on_restore_action(self, event):  # noqa: C901
             elif is_backup_id_timeline:
                 restore_stanza_timeline = timelines[backup_id]
             else:
+                backups_list = list(self._list_backups(show_failed=False).values())
+                timelines_list = self._list_timelines()
+                if (
+                    restore_to_time == "latest"
+                    and timelines_list is not None
+                    and max(timelines_list.values() or [backups_list[0]]) not in backups_list
+                ):
+                    error_message = "There is no base backup created from the latest timeline"
+                    logger.error(f"Restore failed: {error_message}")
+                    event.fail(error_message)
+                    return
                 restore_stanza_timeline = self._get_nearest_timeline(restore_to_time)
                 if not restore_stanza_timeline:
                     error_message = f"Can't find the nearest timeline before timestamp {restore_to_time} to restore"
@@ -1150,11 +1163,8 @@ def _pre_restore_checks(self, event: ActionEvent) -> bool:
             event.fail(validation_message)
             return False
 
-        if not event.params.get("backup-id") and event.params.get("restore-to-time") in (
-            None,
-            "latest",
-        ):
-            error_message = "Missing backup-id or non-latest restore-to-time parameter to be able to do restore"
+        if not event.params.get("backup-id") and event.params.get("restore-to-time") is None:
+            error_message = "Either backup-id or restore-to-time parameters need to be provided to be able to do restore"
             logger.error(f"Restore failed: {error_message}")
             event.fail(error_message)
             return False

diff --git a/tests/unit/test_backups.py b/tests/unit/test_backups.py
@@ -1359,6 +1359,10 @@ def test_get_nearest_timeline(harness):
         _list_timelines.return_value = dict[str, tuple[str, str]]({
             "2023-02-24T05:00:00Z": ("test-stanza", "2")
         })
+        assert harness.charm.backup._get_nearest_timeline("latest") == tuple[str, str]((
+            "test-stanza",
+            "2",
+        ))
         assert harness.charm.backup._get_nearest_timeline("2025-01-01 00:00:00") == tuple[
             str, str
         ](("test-stanza", "2"))
@@ -1567,6 +1571,49 @@ def test_on_restore_action(harness):
         mock_event.fail.assert_not_called()
         mock_event.set_results.assert_called_once_with({"restore-status": "restore started"})
 
+        # Test a failed PITR with only the restore-to-time parameter equal to latest
+        # (it should fail when there is no base backup created from the latest timeline).
+        mock_event.reset_mock()
+        _empty_data_files.reset_mock()
+        with harness.hooks_disabled():
+            harness.update_relation_data(
+                peer_rel_id,
+                harness.charm.app.name,
+                {
+                    "restore-timeline": "",
+                    "restore-to-time": "",
+                    "restore-stanza": "",
+                },
+            )
+        _update_config.reset_mock()
+        mock_event.params = {"restore-to-time": "latest"}
+        harness.charm.backup._on_restore_action(mock_event)
+        _empty_data_files.assert_not_called()
+        _restart_database.assert_not_called()
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {}
+        _update_config.assert_not_called()
+        mock_event.set_results.assert_not_called()
+        mock_event.fail.assert_called_once()
+
+        # Test a successful PITR with only the restore-to-time parameter equal to latest.
+        mock_event.reset_mock()
+        mock_event.params = {"restore-to-time": "latest"}
+        _list_backups.return_value = {
+            "2023-01-01T09:00:00Z": (harness.charm.backup.stanza_name, "1"),
+            "2024-02-24T05:00:00Z": (harness.charm.backup.stanza_name, "2"),
+        }
+        harness.charm.backup._on_restore_action(mock_event)
+        _empty_data_files.assert_called_once()
+        _restart_database.assert_not_called()
+        assert harness.get_relation_data(peer_rel_id, harness.charm.app) == {
+            "restore-timeline": "2",
+            "restore-to-time": "latest",
+            "restore-stanza": f"{harness.charm.model.name}.{harness.charm.cluster_name}",
+        }
+        _update_config.assert_called_once()
+        mock_event.fail.assert_not_called()
+        mock_event.set_results.assert_called_once_with({"restore-status": "restore started"})
+
 
 def test_pre_restore_checks(harness):
     with (