Limit result set sizes (fix #1068)

beetsplug/chroma.py

@@ -29,6 +29,8 @@ API_KEY = '1vOwZtEn'
 SCORE_THRESH = 0.5
 TRACK_ID_WEIGHT = 10.0
 COMMON_REL_THRESH = 0.6  # How many tracks must have an album in common?
+MAX_RECORDINGS = 5
+MAX_RELEASES = 5
 
 log = logging.getLogger('beets')
 
@@ -46,6 +48,15 @@ _fingerprints = {}
 _acoustids = {}
 
 
+def prefix(it, count):
+    """Truncate an iterable to at most `count` items.
+    """
+    for i, v in enumerate(it):
+        if i >= count:
+            break
+        yield v
+
+
 def acoustid_match(path):
     """Gets metadata for a file from Acoustid and populates the
     _matches, _fingerprints, and _acoustids dictionaries accordingly.
@@ -88,7 +99,9 @@ def acoustid_match(path):
         if 'releases' in recording:
             release_ids += [rel['id'] for rel in recording['releases']]
 
-    log.debug(u'chroma: matched recordings {0}'.format(recording_ids))
+    log.debug(u'chroma: matched recordings {0} on releases {1}'.format(
+        recording_ids, release_ids,
+    ))
     _matches[path] = recording_ids, release_ids
 
 
@@ -137,7 +150,7 @@ class AcoustidPlugin(plugins.BeetsPlugin):
 
     def candidates(self, items, artist, album, va_likely):
         albums = []
-        for relid in _all_releases(items):
+        for relid in prefix(_all_releases(items), MAX_RELEASES):
             album = hooks.album_for_mbid(relid)
             if album:
                 albums.append(album)
@@ -151,7 +164,7 @@ class AcoustidPlugin(plugins.BeetsPlugin):
 
         recording_ids, _ = _matches[item.path]
         tracks = []
-        for recording_id in recording_ids:
+        for recording_id in prefix(recording_ids, MAX_RECORDINGS):
             track = hooks.track_for_mbid(recording_id)
             if track:
                 tracks.append(track)

docs/changelog.rst

@@ -82,6 +82,9 @@ Fixes:
   alongside converted files. Thanks to Ángel Alonso. :bug:`1050`, :bug:`1055`
 * There is no longer a "conflict" between two plugins that declare the same
   field with the same type. Thanks to Peter Schnebel. :bug:`1059` :bug:`1061`
+* :doc:`/plugins/chroma`: Limit the number of releases and recordings fetched
+  as the result of an Acoustid match to avoid extremely long processing times
+  for very popular music. :bug:`1068`
 
 
 1.3.8 (September 17, 2014)