Fix #777: Added a prune_library management command to remove obsolete metadata

api/funkwhale_api/music/management/commands/prune_library.py

+from argparse import RawTextHelpFormatter
+
+from django.core.management.base import BaseCommand
+from django.core.management.base import CommandError
+
+from django.db import transaction
+
+from funkwhale_api.music import models, tasks
+
+
+class Command(BaseCommand):
+    help = """
+    Remove tracks, albums and artists that are not associated with any file from the instance library:
+
+    - Tracks without uploads are deleted, if the --tracks flag is passed
+    - Albums without tracks are deleted, if the --albums flag is passed
+    - Artists without albums are deleted, if the --artists flag is passed
+
+    Tracks with associated favorites, playlists or listening won't be deleted
+    by default, unless you pass the corresponding --ignore-* flags.
+
+    """
+
+    def create_parser(self, *args, **kwargs):
+        parser = super().create_parser(*args, **kwargs)
+        parser.formatter_class = RawTextHelpFormatter
+        return parser
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "--no-dry-run",
+            action="store_false",
+            dest="dry_run",
+            default=True,
+            help="Disable dry run mode and apply pruning for real on the database",
+        )
+        parser.add_argument(
+            "--artists",
+            action="store_true",
+            dest="prune_artists",
+            default=False,
+            help="Prune artists without albums/tracks",
+        )
+        parser.add_argument(
+            "--albums",
+            action="store_true",
+            dest="prune_albums",
+            default=False,
+            help="Prune albums without tracks",
+        )
+        parser.add_argument(
+            "--tracks",
+            action="store_true",
+            dest="prune_tracks",
+            default=False,
+            help="Prune tracks without uploads",
+        )
+
+        parser.add_argument(
+            "--ignore-favorites",
+            action="store_false",
+            dest="exclude_favorites",
+            default=True,
+            help="Allow favorited tracks to be pruned",
+        )
+
+        parser.add_argument(
+            "--ignore-playlists",
+            action="store_false",
+            dest="exclude_playlists",
+            default=True,
+            help="Allow tracks included in playlists to be pruned",
+        )
+
+        parser.add_argument(
+            "--ignore-listenings",
+            action="store_false",
+            dest="exclude_listenings",
+            default=True,
+            help="Allow tracks with listening history to be pruned",
+        )
+
+    @transaction.atomic
+    def handle(self, *args, **options):
+        if not any(
+            [options["prune_albums"], options["prune_tracks"], options["prune_artists"]]
+        ):
+            raise CommandError(
+                "You need to provide at least one of the --tracks, --albums or --artists flags"
+            )
+
+        if options["dry_run"]:
+            self.stdout.write("Dry-run on, will not commit anything")
+        else:
+            self.stdout.write("Dry-run off, *pruning for real*")
+        self.stdout.write("")
+        if options["prune_tracks"]:
+            prunable = tasks.get_prunable_tracks(
+                exclude_favorites=options["exclude_favorites"],
+                exclude_playlists=options["exclude_playlists"],
+                exclude_listenings=options["exclude_listenings"],
+            )
+            pruned_total = prunable.count()
+            total = models.Track.objects.count()
+            if options["dry_run"]:
+                self.stdout.write(
+                    "Would prune {}/{} tracks".format(pruned_total, total)
+                )
+            else:
+                self.stdout.write("Deleting {}/{} tracks…".format(pruned_total, total))
+                prunable.delete()
+
+        if options["prune_albums"]:
+            prunable = tasks.get_prunable_albums()
+            pruned_total = prunable.count()
+            total = models.Album.objects.count()
+            if options["dry_run"]:
+                self.stdout.write(
+                    "Would prune {}/{} albums".format(pruned_total, total)
+                )
+            else:
+                self.stdout.write("Deleting {}/{} albums…".format(pruned_total, total))
+                prunable.delete()
+
+        if options["prune_artists"]:
+            prunable = tasks.get_prunable_artists()
+            pruned_total = prunable.count()
+            total = models.Artist.objects.count()
+            if options["dry_run"]:
+                self.stdout.write(
+                    "Would prune {}/{} artists".format(pruned_total, total)
+                )
+            else:
+                self.stdout.write("Deleting {}/{} artists…".format(pruned_total, total))
+                prunable.delete()
+
+        self.stdout.write("")
+        if options["dry_run"]:
+            self.stdout.write(
+                "Nothing was pruned, rerun this command with --no-dry-run to apply the changes"
+            )
+        else:
+            self.stdout.write("Pruning completed!")
+
+        self.stdout.write("")

api/funkwhale_api/music/tasks.py

@@ -568,3 +568,31 @@ def clean_transcoding_cache():
         .order_by("id")
     )
     return candidates.delete()
+
+
+def get_prunable_tracks(
+    exclude_favorites=True, exclude_playlists=True, exclude_listenings=True
+):
+    """
+    Returns a list of tracks with no associated uploads,
+    excluding the one that were listened/favorited/included in playlists.
+    """
+
+    queryset = models.Track.objects.all()
+    queryset = queryset.filter(uploads__isnull=True)
+    if exclude_favorites:
+        queryset = queryset.filter(track_favorites__isnull=True)
+    if exclude_playlists:
+        queryset = queryset.filter(playlist_tracks__isnull=True)
+    if exclude_listenings:
+        queryset = queryset.filter(listenings__isnull=True)
+
+    return queryset
+
+
+def get_prunable_albums():
+    return models.Album.objects.filter(tracks__isnull=True)
+
+
+def get_prunable_artists():
+    return models.Artist.objects.filter(tracks__isnull=True, albums__isnull=True)

api/tests/music/test_commands.py

 import os
+import pytest
 
 from funkwhale_api.music.management.commands import fix_uploads
+from funkwhale_api.music.management.commands import prune_library
 
 DATA_DIR = os.path.dirname(os.path.abspath(__file__))
 
@@ -73,3 +75,78 @@ def test_fix_uploads_mimetype(factories, mocker):
 
     assert upload1.mimetype == "audio/mpeg"
     assert upload2.mimetype == "audio/something"
+
+
+def test_prune_library_dry_run(factories):
+    prunable = factories["music.Track"]()
+    not_prunable = factories["music.Track"]()
+    c = prune_library.Command()
+    options = {
+        "prune_artists": True,
+        "prune_albums": True,
+        "prune_tracks": True,
+        "exclude_favorites": False,
+        "exclude_listenings": False,
+        "exclude_playlists": False,
+        "dry_run": True,
+    }
+    c.handle(**options)
+
+    for t in [prunable, not_prunable]:
+        # nothing pruned, because dry run
+        t.refresh_from_db()
+
+
+def test_prune_library(factories, mocker):
+    prunable_track = factories["music.Track"]()
+    not_prunable_track = factories["music.Track"]()
+    prunable_tracks = prunable_track.__class__.objects.filter(pk=prunable_track.pk)
+    get_prunable_tracks = mocker.patch(
+        "funkwhale_api.music.tasks.get_prunable_tracks", return_value=prunable_tracks
+    )
+
+    prunable_album = factories["music.Album"]()
+    not_prunable_album = factories["music.Album"]()
+    prunable_albums = prunable_album.__class__.objects.filter(pk=prunable_album.pk)
+    get_prunable_albums = mocker.patch(
+        "funkwhale_api.music.tasks.get_prunable_albums", return_value=prunable_albums
+    )
+
+    prunable_artist = factories["music.Artist"]()
+    not_prunable_artist = factories["music.Artist"]()
+    prunable_artists = prunable_artist.__class__.objects.filter(pk=prunable_artist.pk)
+    get_prunable_artists = mocker.patch(
+        "funkwhale_api.music.tasks.get_prunable_artists", return_value=prunable_artists
+    )
+
+    c = prune_library.Command()
+    options = {
+        "exclude_favorites": mocker.Mock(),
+        "exclude_listenings": mocker.Mock(),
+        "exclude_playlists": mocker.Mock(),
+        "prune_artists": True,
+        "prune_albums": True,
+        "prune_tracks": True,
+        "dry_run": False,
+    }
+    c.handle(**options)
+
+    get_prunable_tracks.assert_called_once_with(
+        exclude_favorites=options["exclude_favorites"],
+        exclude_listenings=options["exclude_listenings"],
+        exclude_playlists=options["exclude_playlists"],
+    )
+    get_prunable_albums.assert_called_once()
+    get_prunable_artists.assert_called_once()
+
+    with pytest.raises(prunable_track.DoesNotExist):
+        prunable_track.refresh_from_db()
+
+    with pytest.raises(prunable_album.DoesNotExist):
+        prunable_album.refresh_from_db()
+
+    with pytest.raises(prunable_artist.DoesNotExist):
+        prunable_artist.refresh_from_db()
+
+    for o in [not_prunable_track, not_prunable_album, not_prunable_artist]:
+        o.refresh_from_db()

api/tests/music/test_tasks.py

@@ -637,3 +637,72 @@ def test_clean_transcoding_cache(preferences, now, factories):
 
     with pytest.raises(u1.__class__.DoesNotExist):
         u1.refresh_from_db()
+
+
+def test_get_prunable_tracks(factories):
+    prunable_track = factories["music.Track"]()
+    # non prunable tracks
+    factories["music.Upload"]()
+    factories["favorites.TrackFavorite"]()
+    factories["history.Listening"]()
+    factories["playlists.PlaylistTrack"]()
+
+    assert list(tasks.get_prunable_tracks()) == [prunable_track]
+
+
+def test_get_prunable_tracks_include_favorites(factories):
+    prunable_track = factories["music.Track"]()
+    favorited = factories["favorites.TrackFavorite"]().track
+    # non prunable tracks
+    factories["favorites.TrackFavorite"](track__playable=True)
+    factories["music.Upload"]()
+    factories["history.Listening"]()
+    factories["playlists.PlaylistTrack"]()
+
+    qs = tasks.get_prunable_tracks(exclude_favorites=False).order_by("id")
+    assert list(qs) == [prunable_track, favorited]
+
+
+def test_get_prunable_tracks_include_playlists(factories):
+    prunable_track = factories["music.Track"]()
+    in_playlist = factories["playlists.PlaylistTrack"]().track
+    # non prunable tracks
+    factories["favorites.TrackFavorite"]()
+    factories["music.Upload"]()
+    factories["history.Listening"]()
+    factories["playlists.PlaylistTrack"](track__playable=True)
+
+    qs = tasks.get_prunable_tracks(exclude_playlists=False).order_by("id")
+    assert list(qs) == [prunable_track, in_playlist]
+
+
+def test_get_prunable_tracks_include_listenings(factories):
+    prunable_track = factories["music.Track"]()
+    listened = factories["history.Listening"]().track
+    # non prunable tracks
+    factories["favorites.TrackFavorite"]()
+    factories["music.Upload"]()
+    factories["history.Listening"](track__playable=True)
+    factories["playlists.PlaylistTrack"]()
+
+    qs = tasks.get_prunable_tracks(exclude_listenings=False).order_by("id")
+    assert list(qs) == [prunable_track, listened]
+
+
+def test_get_prunable_albums(factories):
+    prunable_album = factories["music.Album"]()
+    # non prunable album
+    factories["music.Track"]().album
+
+    assert list(tasks.get_prunable_albums()) == [prunable_album]
+
+
+def test_get_prunable_artists(factories):
+    prunable_artist = factories["music.Artist"]()
+    # non prunable artist
+    non_prunable_artist = factories["music.Artist"]()
+    non_prunable_album_artist = factories["music.Artist"]()
+    factories["music.Track"](artist=non_prunable_artist)
+    factories["music.Track"](album__artist=non_prunable_album_artist)
+
+    assert list(tasks.get_prunable_artists()) == [prunable_artist]

changes/changelog.d/777.enhancement

+Added a prune_library management command to remove obsolete metadata from the database (#777)

changes/notes.rst

@@ -34,3 +34,13 @@ enabled in a future release).
 
 If you want to start building an app on top of Funkwhale's API, please check-out
 `https://docs.funkwhale.audio/api.html`_ and `https://docs.funkwhale.audio/developers/authentication.html`_.
+
+Prune library command
+^^^^^^^^^^^^^^^^^^^^^
+
+Users are often surprised by Funkwhale's tendency to keep track, album and artist
+metadata even if no associated files exist.
+
+To help with that, we now offer a ``prune_library`` management command you can run
+to purge your database from obsolete entry. `Please refer to our documentation
+for usage instructions <https://docs.funkwhale.audio/admin/commands.html#pruning-library>`_.

docs/admin/commands.rst

+Management commands
+===================
+
+Pruning library
+---------------
+
+Because Funkwhale is a multi-user and federated audio server, we don't delete any artist, album
+and track objects in the database when you delete the corresponding files.
+
+This is on purpose, because those objects may be referenced in user playlists, favorites,
+listening history or on other instances, or other users could have upload files matching
+linked to those entities in their own private libraries.
+
+Therefore, Funkwhale has a really conservative approach and doesn't delete metadata when
+audio files are deleted.
+
+This behaviour can be problematic in some situations though, e.g. if you imported
+a lot of wrongly tagged files, then deleted the files to reimport them later.
+
+To help with that, we provide a management you can run on the server and that will effectively
+prune you library from track, album and artist metadata that is not tied to any file:
+
+.. code-block:: sh
+
+    # print help
+    python manage.py prune_library --help
+
+    # prune tracks with no uploads
+    python manage.py prune_library --tracks
+
+    # prune albums with no tracks
+    python manage.py prune_library --albums
+
+    # prune artists with no tracks/albums
+    python manage.py prune_library --artists
+
+    # prune everything (tracks, albums and artists)
+    python manage.py prune_library --tracks --albums --artists
+
+The ``prune_library`` command will not delete anything by default, and only gives
+you an estimate of how many database objects would be affected by the pruning.
+
+Once you have reviewed the output and are comfortable with the changes, you should rerun
+the command with the ``--no-dry-run`` flag to disable dry run mode and actually apply
+the changes on the database.
+
+.. warning::
+
+    Running this command with ``--no-dry-run`` is irreversible. Unless you have a backup,
+    there will be no way to retrieve the deleted data.
+
+.. note::
+
+    The command will exclude tracks that are favorited, included in playlists or listening
+    history by default. If you want to include those in the pruning process as well,
+    add the corresponding ``--ignore-favorites``, ``--ignore-playlists`` and ``--ignore-listenings``
+    flags.

docs/admin/index.rst

@@ -22,6 +22,7 @@ Administration
    :maxdepth: 2
 
    django
+   commands
    url
    upgrading