ArtResizer holds file handles for every album art created when using the convert plugin

[afontenot]

Problem

I was trying to convert a large number of files with beet convert -d <dest>, and eventually got an error:

error: convert: couldn't invoke 'ffmpeg -i <SOURCEFILE> -y -vn -acodec libopus -ab 96k <DESTFILE>': [Errno 24] Too many open files

So far I'm on my third invocation of beet convert (existing files get skipped, so it eventually completes). Looking at lsof, it seems that many hundreds of file handles are kept open in /tmp/beets/util_artresizer/, which can run up against default OS limits pretty easily.

I don't think the art resizer should need to keep file handles open, it could just keep the path to the file in case it is needed again.

Setup

• OS: Ubuntu 22.04.4
• Python version: 3.10.12
• beets version: 2.2.0
• Turning off plugins made problem go away (yes/no): n/a (problem affects a plugin)

My configuration (output of beet config) is:

directory: /mnt/data/audio
# --------------- Main ---------------

library: ~/.config/beets/music.blb
pluginpath: ~/.local/share/beets/plugins

# --------------- Plugins ---------------

plugins: convert copyartifacts fetchart inline permissions replaygain zero info mbsync
medium_rec_thresh: -1.0

import:
    detail: yes
    move: yes
    timid: yes
    searchlimit: 8
copyartifacts:
    extensions: .cue .log
    print_ignored: no
zero:
    fields: albumartist_credit albumstatus artist_credit acoustid_id acoustid_fingerprint
    auto: yes
    keep_fields: []
    update_database: no
art_filename: folder

# --------------- Tagging ---------------

per_disc_numbering: yes
incremental: yes
artist_credit: yes
paths:
    albumtype:soundtrack: soundtracks/$authorcredit/$album ($year)%aunique{}/%if{$multidisc,Disc $disc/}$track - $title
    albumtype:single: singles/$albumartist/$album ($year)%aunique{}/%if{$multidisc,Disc $disc/}$track - $title
    albumgenre:soundtrack: soundtracks/$authorcredit/$album ($year)%aunique{}/%if{$multidisc,Disc $disc/}$track - $title
    albumgenre:classical: composers/$authorcredit/$album ($year)%aunique{}/%if{$multidisc,Disc $disc/}$track - $title
    albumgenre:instrumental: composers/$authorcredit/$album ($year)%aunique{}/%if{$multidisc,Disc $disc/}$track - $title
    albumgenre:experimental: experimental/$albumartist/$album ($year)%aunique{}/%if{$multidisc,Disc $disc/}$track - $title
    albumgenre:jazz: jazz/$albumartist/$album ($year)%aunique{}/%if{$multidisc,Disc $disc/}$track - $title
    comp: music/$albumartist/$album ($year)%aunique{}/%if{$multidisc,Disc $disc/}$track - $title
    default: music/$albumartist/$album ($year)%aunique{}/%if{$multidisc,Disc $disc/}$track - $title

aunique:
    keys: albumartist album year
    disambiguators: albummediatype albummedia label catalognum
album_fields:
    albummediatype: "m_0 = items[0].get(\"mediatype\")\nif m_0 and all(m_0 == item.get(\"mediatype\") for item in items[1:]):\n    return m_0\nreturn \"\"\n"
    albummedia: "m_0 = items[0].get(\"media\")\nif m_0 and all(m_0 == item.get(\"media\") for item in items[1:]):\n    return m_0\nreturn \"\"\n"
    albumgenre: "try:\n    return classification\nexcept NameError:\n    pass\ntry:\n    return genre.lower()\nexcept NameError:\n    return \"\"\n"
    authorcredit: "c_0 = items[0].get(\"composer\")\nif c_0 and all(c_0 == item.get(\"composer\") for item in items[1:]):\n    return c_0\na_0 = items[0].get(\"artist\")\nif a_0 and all(a_0 == item.get(\"artist\") for item in items[1:]):\n    return a_0\nreturn albumartist\n"
item_fields:
    multidisc: 1 if disctotal > 1 else 0

# --------------- Paths ---------------

path_sep_replace: "\u29F8"
replace:
    \\: "\u29F8"
    ^\.: ''
    '[\x00-\x1f]': ''
    \.$: ''
    \s+$: ''
convert:
    format: opus
    never_convert_lossy_files: yes
    album_art_maxwidth: 1080
    dest:
    pretend: no
    link: no
    hardlink: no
    threads: 8
    id3v23: inherit
    formats:
        aac:
            command: ffmpeg -i $source -y -vn -acodec aac -aq 1 $dest
            extension: m4a
        alac:
            command: ffmpeg -i $source -y -vn -acodec alac $dest
            extension: m4a
        flac: ffmpeg -i $source -y -vn -acodec flac $dest
        mp3: ffmpeg -i $source -y -vn -aq 2 $dest
        opus: ffmpeg -i $source -y -vn -acodec libopus -ab 96k $dest
        ogg: ffmpeg -i $source -y -vn -acodec libvorbis -aq 3 $dest
        wma: ffmpeg -i $source -y -vn -acodec wmav2 -vn $dest
    max_bitrate:
    auto: no
    auto_keep: no
    tmpdir:
    quiet: no
    embed: yes
    paths: {}
    no_convert: ''
    copy_album_art: no
    delete_originals: no
    playlist:
replaygain:
    backend: ffmpeg
    overwrite: no
    auto: yes
    threads: 8
    parallel_on_import: no
    per_disc: no
    peak: 'true'
    targetlevel: 89
    r128: [Opus]
    r128_targetlevel: 84
pathfields: {}
fetchart:
    auto: yes
    minwidth: 0
    maxwidth: 0
    quality: 0
    max_filesize: 0
    enforce_ratio: no
    cautious: no
    cover_names:
    - cover
    - front
    - art
    - album
    - folder
    sources:
    - filesystem
    - coverart
    - itunes
    - amazon
    - albumart
    - cover_art_url
    store_source: no
    high_resolution: no
    deinterlace: no
    cover_format:
    google_key: REDACTED
    google_engine: 001442825323518660753:hrh5ch1gjzm
    fanarttv_key: REDACTED
    lastfm_key: REDACTED
permissions:
    file: '644'
    dir: '755'