Implemented optional NTP client test before retention operations

CHANGELOG

@@ -6,13 +6,12 @@
       - with button to select forget/prune operation
       - With explanation link to restic
     - prune operation: default max unsed ?
-    - Operation planifier:
+    - Operation planifier
       - backups
       - cleaner (forget / check / prune, each having different planification (at least for check --read-data))
       - Launch now
    - NPBackup Operation mode
       - manages multiple repos with generic key (restic key add) or specified key
-  !- NTP server
   - GUI --help parameter should intercept stdout and show results in a popup
 
  
@@ -37,7 +36,9 @@
   !- Operation center
     - GUI operation center allowing to mass execute actions on repos / groups
     - CLI operation center via `--group-operation --repo-group=somegroup`
-    !- Implemented retention policies
+    - Implemented retention policies
+      - Optional time server update to make sure we don't drift before doing retention operations
+      ! Optional repo check before doing retention operations
     !- Operation planifier allows to create scheduled tasks for operations
       !- Implemented scheduled task creator for Windows & Unix
          !(simple list of tasks, actions, stop on error)
@@ -71,6 +72,7 @@
   - Allow a 30 seconds grace period for child processes to close before asking them nicely, and than not nicely to quit
   - Fully refactored prometheus metrics parser to be able to read restic standard or json outputs
   - Reimplmented auto upgrade after CLI/GUI split
+  - --dry-run now works with other commands than backup
   - Added initial tests
 
 ## 2.2.2 - 14/12/2023 (internal build only)
@@ -189,7 +191,7 @@
   - Fix error message in logs when repo is not initialized
 
 ## v2.2.0 - rc1 - 02/02/2023
-  - Added a full auto-upgrade solution:
+  - Added a full auto-upgrade solution
     - Aupgrade client integrated into NPBackup, that can be called manually via --auto-upgrade or automatically run every n backups
     - Upgrade server which servers files and their metadata
   - Added a gui to create a scheduled task under Windows
@@ -241,9 +243,9 @@
   - Fix for ruamel.yaml global objects being modified out of current scope encrypting current config while saving
   - Fix npbackup could not start when no config file was present
   - Drastically improve ls operation speed by changing command_runner method from poller to monitor (no live output) except for backup operation
-  - Compiler:
+  - Compiler
     - Compile python 3.7 and 3.10 targets so we also get to use Windows 7 which can't run python > 3.7
-  - Installer:
+  - Installer
     - Moved task creation process to npbackup so we can recreate tasks on systems where npbackup is already installed
 
 ## v1.8.0
@@ -266,7 +268,7 @@
   - Allow setting additional prometheus labels
   - Fix gui snapshot contents don't show duplicate parents on Windows when backing up 'c:\foo' and 'C:\bar'
   - Internal code cleanup
-  - Installer:
+  - Installer
     - Make sure we don't overwrite destination configuration file if existing
 
 ## v1.5.3

npbackup/configuration.py

@@ -191,7 +191,7 @@ empty_config_dict = {
                     "yearly": 3,
                     "tags": [],
                     "keep_within": True,
-                    "ntp_time_server": None,  # TODO
+                    "ntp_server": None,
                 },
                 # "prune_max_unused": None,  # TODO
                 # "prune_max_repack_size": None,  # TODO

npbackup/core/runner.py

@@ -24,6 +24,7 @@ from command_runner import command_runner
 from ofunctions.threading import threaded
 from ofunctions.platform import os_arch
 from ofunctions.misc import BytesConverter
+import ntplib
 from npbackup.restic_metrics import (
     restic_str_output_to_json,
     restic_json_to_prometheus,
@@ -118,6 +119,21 @@ def metric_writer(
     return backup_too_small
 
 
+def get_ntp_offset(ntp_server: str) -> Optional[float]:
+    """
+    Get current time offset from ntp server
+    """
+    try:
+        client = ntplib.NTPClient()
+        response = client.request(ntp_server)
+        return response.offset
+    except ntplib.NTPException as exc:
+        logger.error(f"Cannot get NTP offset from {ntp_server}: {exc}")
+    except Exception as exc:
+        logger.error(f"Cannot reach NTP server {ntp_server}: {exc}")
+    return None
+
+
 class NPBackupRunner:
     """
     Wraps ResticRunner into a class that is usable by NPBackup
@@ -1161,6 +1177,17 @@ class NPBackupRunner:
             self.write_logs(f"Forgetting snapshots {snapshots}", level="info")
             result = self.restic_runner.forget(snapshots)
         elif use_policy:
+            # Let's check if we can get a valid NTP server offset
+            # If offset is too big, we won't apply policy
+            # Offset should not be higher than 10 minutes, eg 600 seconds
+            ntp_server = self.repo_config.g("repo_opts.retention_policy.ntp_server")
+            if ntp_server:
+                offset = get_ntp_offset(ntp_server)
+                if not offset or offset >= 600:
+                    msg = f"Offset from NTP server {ntp_server} is too high: {int(offset)} seconds. Won't apply policy"
+                    self.write_logs(msg, level="critical")
+                    return self.convert_to_json_output(False, msg)
+
             # Build policiy from config
             policy = {}
             for entry in ["last", "hourly", "daily", "weekly", "monthly", "yearly"]:

npbackup/gui/config.py

@@ -1325,7 +1325,7 @@ def config_gui(full_config: dict, config_file: str):
             [
                 sg.Text(_t("config_gui.optional_ntp_server_uri"), size=(40, 1)),
                 sg.Input(
-                    key="repo_opts.retention_policy.ntp_time_server", size=(50, 1)
+                    key="repo_opts.retention_policy.ntp_server", size=(50, 1)
                 ),
             ],
         ]

npbackup/requirements.txt

@@ -25,3 +25,4 @@ i18nice>=0.6.2
 packaging
 pywin32; platform_system == "Windows"
 imageio; platform_system == "Darwin"
+ntplib>=0.4.0

npbackup/translations/config_gui.en.yml

@@ -120,7 +120,7 @@ en:
   keep_within: Keep within
   keep_within_explanation: Keep only the last n snapshots within the last m snapshots
   keep_tags: Keep snapshots with the following tags
-  optional_ntp_server_uri: Optional NTP server URL
+  optional_ntp_server_uri: Optional NTP server URI
 
   # repo / group managmeent
   repo_group: Repo group