Retry Garmin stat downloads on transient failures (#308)

Author: deewhyarc-glitch

garmindb/download.py

@@ -113,7 +113,18 @@ def __get_stat(self, stat_function, directory, date, days, overwrite):
             download_date = date + datetime.timedelta(days=day)
             # always overwrite for yesterday and today since the last download may have been a partial result
             delta = datetime.datetime.now().date() - download_date
-            stat_function(directory, download_date, overwrite or delta.days <= self.download_days_overlap)
+            stat_overwrite = overwrite or delta.days <= self.download_days_overlap
+            for attempt in range(1, 6):
+                try:
+                    stat_function(directory, download_date, stat_overwrite)
+                    break
+                except Exception as e:
+                    if attempt == 5:
+                        root_logger.error("Failed to download %s after %d attempts: %s", download_date, attempt, e)
+                    else:
+                        backoff_seconds = attempt * 5
+                        root_logger.warning("Retrying %s after error on attempt %d/%d: %s", download_date, attempt, 5, e)
+                        time.sleep(backoff_seconds)
             # pause for a second between every page access
             time.sleep(1)
 
@@ -296,8 +307,9 @@ def __get_hrv_day(self, directory, day, overwrite=False):
         url = f'{self.garmin_connect_hrv_url}/{date_str}'
         try:
             self.save_json_to_file(json_filename, self.garmin.connectapi(url), overwrite)
-        except GarminConnectAuthError as e:
-            root_logger.error("Exception getting daily summary %s", e)
+        except Exception as e:
+            root_logger.error("Exception getting hrv for %s: %s", date_str, e)
+            raise
 
     def get_hrv(self, directory, date, days, overwrite):
         """Download the heart rate variability (HRV) data from Garmin Connect and save to a JSON file."""

test/test_download.py

@@ -0,0 +1,59 @@
+"""Tests for download retry behavior."""
+
+__author__ = "Tom Goetz"
+__copyright__ = "Copyright Tom Goetz"
+__license__ = "GPL"
+
+import datetime
+import unittest
+from unittest import mock
+
+from garmindb.download import Download
+
+
+class FakeConfig:
+    """Minimal config stub for Download tests."""
+
+    def get_session_file(self):
+        return "/tmp/garth_session"
+
+    def get_garmin_base_domain(self):
+        return "garmin.com"
+
+
+class TestDownload(unittest.TestCase):
+    def setUp(self):
+        self.download = Download(FakeConfig())
+
+    def test_get_stat_retries_until_success(self):
+        attempts = []
+
+        def flaky_stat(directory, day, overwrite):
+            attempts.append((directory, day, overwrite))
+            if len(attempts) < 3:
+                raise RuntimeError("temporary HRV gap")
+
+        start_date = datetime.date(2026, 3, 1)
+        with mock.patch("garmindb.download.time.sleep"):
+            self.download._Download__get_stat(flaky_stat, "/tmp/hrv", start_date, 1, False)
+
+        self.assertEqual(len(attempts), 3)
+        self.assertEqual(attempts[0][0], "/tmp/hrv")
+        self.assertEqual(attempts[0][1], start_date)
+
+    def test_get_stat_stops_after_five_failures(self):
+        attempts = []
+
+        def always_fail(directory, day, overwrite):
+            attempts.append((directory, day, overwrite))
+            raise RuntimeError("persistent HRV gap")
+
+        start_date = datetime.date(2026, 3, 1)
+        with mock.patch("garmindb.download.time.sleep"):
+            self.download._Download__get_stat(always_fail, "/tmp/hrv", start_date, 1, False)
+
+        self.assertEqual(len(attempts), 5)
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)