feat: wire the mutagen tagger into the worker loop

worker/lyra_worker/main.py

@@ -4,7 +4,7 @@ from lyra_worker.claim import claim_next
 from lyra_worker.config import get_config
 from lyra_worker.db import wait_for_db
 from lyra_worker.pipeline import run_pipeline
-from lyra_worker.registry import build_adapters, build_resolver
+from lyra_worker.registry import build_adapters, build_resolver, build_tagger
 
 IDLE_SLEEP = 2.0
 
@@ -13,6 +13,7 @@ def run_forever() -> None:
     conn = wait_for_db()
     adapters = build_adapters(get_config(conn))
     resolver = build_resolver()
+    tagger = build_tagger()
     print(f"worker: {len(adapters)} adapter(s) enabled: {[a.name for a in adapters]}", flush=True)
     print("worker: waiting for jobs", flush=True)
     try:
@@ -22,7 +23,7 @@ def run_forever() -> None:
                 time.sleep(IDLE_SLEEP)
                 continue
             print(f"worker: claimed job {job_id}", flush=True)
-            run_pipeline(conn, job_id, adapters, resolver=resolver)
+            run_pipeline(conn, job_id, adapters, resolver=resolver, tagger=tagger)
             print(f"worker: finished job {job_id}", flush=True)
     finally:
         conn.close()

worker/lyra_worker/registry.py

@@ -1,4 +1,5 @@
 from lyra_worker._musicbrainz import MusicBrainzResolver
+from lyra_worker._mutagen import MutagenTagger
 from lyra_worker.adapters._slskd import SlskdClient
 from lyra_worker.adapters._streamrip import StreamripClient
 from lyra_worker.adapters._ytdlp import YtDlpClient
@@ -7,6 +8,7 @@ from lyra_worker.adapters.qobuz import QobuzAdapter
 from lyra_worker.adapters.soulseek import SoulseekAdapter
 from lyra_worker.adapters.youtube import YouTubeAdapter
 from lyra_worker.resolver import MbResolver
+from lyra_worker.tagger import Tagger
 
 
 def build_adapters(config: dict) -> list[SourceAdapter]:
@@ -26,3 +28,8 @@ def build_adapters(config: dict) -> list[SourceAdapter]:
 def build_resolver() -> MbResolver:
     """The MusicBrainz resolver used to canonicalize requests in intake."""
     return MusicBrainzResolver()
+
+
+def build_tagger() -> Tagger:
+    """The tagger that writes canonical metadata onto downloaded files."""
+    return MutagenTagger()

worker/tests/test_tag_pipeline.py

@@ -0,0 +1,49 @@
+import os
+
+from lyra_worker.adapters.youtube import YouTubeAdapter
+from lyra_worker.claim import claim_next
+from lyra_worker.pipeline import run_pipeline
+from lyra_worker.registry import build_tagger
+from lyra_worker.types import MBTarget
+from tests.conftest import insert_request
+from tests.test_youtube_adapter import FakeYtClient
+
+
+def test_build_tagger_returns_a_tagger():
+    t = build_tagger()
+    assert hasattr(t, "tag_album")
+
+
+def test_download_dir_receives_files_and_tagger_runs(conn, tmp_path):
+    # A fake YouTube client that actually writes a file into dest, so a real MutagenTagger-shaped
+    # tagger has something to operate on. Here we use a recording tagger to assert it's invoked
+    # on the album directory the download wrote to.
+    written = {}
+
+    def fake_download(source_ref, dest, on_progress):
+        os.makedirs(dest, exist_ok=True)
+        open(os.path.join(dest, "track.opus"), "wb").close()
+        written["dir"] = dest
+        on_progress(1.0)
+        return {"track_count": 1, "path": dest}
+
+    client = FakeYtClient(results=[{"source_ref": "yt1", "title": "Continuum", "artist": "John Mayer", "track_count": 1}])
+    client.download = fake_download
+
+    class RecordingTagger:
+        def __init__(self):
+            self.seen = None
+
+        def tag_album(self, album_dir, target):
+            self.seen = album_dir
+
+    tagger = RecordingTagger()
+    job_id = insert_request(conn, artist="John Mayer", album="Continuum")
+    claim_next(conn)
+    run_pipeline(conn, job_id, [YouTubeAdapter(client)], tagger=tagger, dest_root=str(tmp_path))
+
+    with conn.cursor() as cur:
+        cur.execute('SELECT state FROM "Job" WHERE id = %s', (job_id,))
+        assert cur.fetchone()[0] == "imported"
+    assert tagger.seen == written["dir"]  # tagger ran on the exact directory the download wrote to
+    assert os.path.isdir(tagger.seen)