Fix LastFM rate limiting dropping scrobbles (f91fdd53 follow-up)

vrobbler/apps/scrobbles/importers/lastfm.py

@@ -1,5 +1,6 @@
 import calendar
 import logging
+import time
 from datetime import datetime, timedelta
 
 import pylast
@@ -138,30 +139,38 @@ class LastFM:
 
         for scrobble in found_scrobbles:
             logger.info(f"Processing {scrobble}")
+            log_dict = {"scrobble": scrobble}
+
+            # Artist/title/album come from the recent-tracks response itself,
+            # no extra API call required.
+            artist = scrobble.track.artist.name if scrobble.track.artist else None
+            log_dict["artist"] = artist
+
+            # Duration and MBID require a per-track `getInfo` API call, which
+            # quickly exhausts Last.fm's rate limit for large historical
+            # imports. Treat them as best-effort so one failure doesn't drop
+            # the whole scrobble.
             run_time = None
             mbid = None
-            artist = None
-
-            log_dict = {"scrobble": scrobble}
             try:
                 run_time = int(scrobble.track.get_duration() / 1000)
                 mbid = scrobble.track.get_mbid()
-                artist = scrobble.track.get_artist().name
-                log_dict["artist"] = artist
                 log_dict["mbid"] = mbid
                 log_dict["run_time"] = run_time
             except pylast.MalformedResponseError as e:
                 logger.warning(e)
             except pylast.WSError as e:
                 logger.info(
-                    "LastFM barfed trying to get the track for {scrobble.track}",
-                    extra=log_dict,
+                    f"LastFM barfed trying to enrich {scrobble.track}", extra=log_dict
                 )
             except pylast.NetworkError as e:
                 logger.info(
-                    "LastFM barfed trying to get the track for {scrobble.track}",
-                    extra=log_dict,
+                    f"LastFM barfed trying to enrich {scrobble.track}", extra=log_dict
                 )
+            finally:
+                # Last.fm rate limit is ~5 req/sec; keep per-track enrichment
+                # calls spaced out so large imports don't trip it.
+                time.sleep(0.2)
 
             if not artist:
                 logger.info(