Retry transient HLS network failures

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.52.29 - 2026-09-07
+
+- Added retry and exponential backoff for temporary HLS segment network failures, including DNS resolution, connection, and socket timeout errors.
+
 ## 0.52.28 - 2026-09-07
 
 - Fixed provider source fallback so playlist-resolution exceptions such as `HTTP 502` fail only the current server and the downloader continues with the remaining same-mode servers.

README.md

@@ -67,7 +67,7 @@ Useful environment variables:
 - `KAIZOKU_DOWNLOAD_DIR=/downloads` for the default library output path.
 - `KAIZOKU_REMOTE_PATH_ROOTS=/downloads,/jellyfin/tv,/jellyfin/movies` to limit remote filesystem browsing; comma-separated and platform path separators are accepted.
 - `KAIZOKU_MODE=sub`, `KAIZOKU_QUALITY=best`, and `KAIZOKU_DEBUG=1` for runtime defaults and diagnostics.
-- `KAIZOKU_SEGMENT_RETRIES=8`, `KAIZOKU_SEGMENT_RETRY_DELAY=1.25`, `KAIZOKU_SEGMENT_RETRY_MAX_DELAY=15`, and `KAIZOKU_SEGMENT_DOWNLOAD_DELAY=0` to tune retry/backoff and optional pacing behavior for native HLS segment downloads.
+- `KAIZOKU_SEGMENT_RETRIES=8`, `KAIZOKU_SEGMENT_RETRY_DELAY=1.25`, `KAIZOKU_SEGMENT_RETRY_MAX_DELAY=15`, and `KAIZOKU_SEGMENT_DOWNLOAD_DELAY=0` to tune retry/backoff and optional pacing behavior for native HLS segment downloads. Retries cover temporary HTTP responses, DNS failures, connection errors, and socket timeouts.
 - `KAIZOKU_MEDIA_HTTP_CLIENT=auto` to let protected HLS segment fetches fall back from Python HTTP to `curl` or curl-impersonate after `HTTP 403`; use `curl` or `urllib` to force one client, and `KAIZOKU_CURL_BIN=/path/to/curl_chrome142` to prefer a specific curl-compatible binary. Playlist, segment, and encryption-key requests preserve provider CDN session cookies for the duration of the download process.
 
 ## Docker

VERSION

@@ -1 +1 @@
-0.52.28
+0.52.29

provider_downloader.py

@@ -420,6 +420,20 @@ def fetch_bytes_with_retries(url, headers=None, timeout=30, retries=None, retry_
             )
             if delay:
                 time.sleep(delay)
+        except (urllib.error.URLError, TimeoutError, ConnectionError) as exc:
+            if attempt >= attempts:
+                raise
+            delay = base_delay * (2 ** attempt)
+            if max_delay:
+                delay = min(delay, max_delay)
+            print(
+                f"{retry_label} had a temporary network failure; retrying in {delay:.1f}s "
+                f"({attempt + 1}/{attempts}): {exc}",
+                file=sys.stderr,
+                flush=True,
+            )
+            if delay:
+                time.sleep(delay)
 
 
 def segment_download_delay_seconds():

test_app.py

@@ -4758,6 +4758,39 @@ https://shard-102.snapcdn.top/anime/show/episode/seg-f1-00083.css
         self.assertEqual(fetch_bytes.call_count, 2)
         sleep.assert_called_once()
 
+    def test_fetch_bytes_with_retries_recovers_from_temporary_dns_failure(self):
+        error = urllib.error.URLError(OSError(-3, "Temporary failure in name resolution"))
+
+        with mock.patch.object(
+            provider_downloader,
+            "fetch_bytes",
+            side_effect=[error, b"video"],
+        ) as fetch_bytes, mock.patch.object(provider_downloader.time, "sleep") as sleep:
+            data = provider_downloader.fetch_bytes_with_retries(
+                "https://cdn.example/video/raw-segment",
+                retries=1,
+                retry_label="segment",
+            )
+
+        self.assertEqual(data, b"video")
+        self.assertEqual(fetch_bytes.call_count, 2)
+        sleep.assert_called_once()
+
+    def test_fetch_bytes_with_retries_raises_dns_failure_after_limit(self):
+        error = urllib.error.URLError(OSError(-3, "Temporary failure in name resolution"))
+
+        with mock.patch.object(provider_downloader, "fetch_bytes", side_effect=error), mock.patch.object(
+            provider_downloader.time, "sleep"
+        ) as sleep:
+            with self.assertRaises(urllib.error.URLError):
+                provider_downloader.fetch_bytes_with_retries(
+                    "https://cdn.example/video/raw-segment",
+                    retries=1,
+                    retry_label="segment",
+                )
+
+        sleep.assert_called_once()
+
     def test_provider_stream_candidates_returns_resolved_sources(self):
         with mock.patch.object(
             provider_downloader,