fix: multiprocessing problems

Author: cwilvx

app/db/engine.py

@@ -1,7 +1,9 @@
 from contextlib import contextmanager
-from sqlalchemy import Engine, event
+from sqlalchemy import Engine, create_engine, event
 from sqlalchemy.orm import sessionmaker
 
+from app.settings import DbPaths
+
 
 @event.listens_for(Engine, "connect")
 def set_sqlite_pragma(dbapi_connection, connection_record):
@@ -14,13 +16,35 @@ def set_sqlite_pragma(dbapi_connection, connection_record):
     cursor.execute("PRAGMA mmap_size=0")
     cursor.close()
 
+class classproperty(property):
+    """
+    A class property decorator.
+    """
+
+    def __get__(self, owner_self, owner_cls):
+        if self.fget:
+            return self.fget(owner_cls)
+
+
 
 class DbEngine:
     """
     The database engine instance.
     """
 
-    engine: Engine
+    _engine: Engine | None = None
+
+    @classproperty
+    def engine(cls) -> Engine:
+        if not cls._engine:
+            cls._engine = create_engine(
+                f"sqlite+pysqlite:///{DbPaths.get_app_db_path()}",
+                echo=False,
+                max_overflow=20,
+                pool_size=10,
+            )
+
+        return cls._engine
 
     @classmethod
     @contextmanager

app/lib/artistlib.py

@@ -1,9 +1,8 @@
-import math
 import os
 import time
+import random
 import urllib
 import requests
-import multiprocessing
 
 from io import BytesIO
 from pathlib import Path
@@ -29,8 +28,6 @@
 PngImagePlugin.MAX_TEXT_CHUNK = LARGE_ENOUGH_NUMBER * (1024**2)
 # https://stackoverflow.com/a/61466412
 
-import random
-
 
 def get_artist_image_link(artist: str):
     """

app/lib/tagger.py

@@ -69,7 +69,7 @@ def extract_thumb_with_overwrite(tracks: list[dict[str, str]]):
                 extract_thumb(
                     track["filepath"], track["albumhash"] + ".webp", overwrite=True
                 )
-            except FileNotFoundError:
+            except (FileNotFoundError, KeyError):
                 continue
 
     @staticmethod

app/settings.py

@@ -29,7 +29,11 @@ def set_config_dir(cls, path: str):
 
     @classmethod
     def get_config_dir(cls):
-        return cls.XDG_CONFIG_DIR or os.path.realpath(".")
+        return (
+            cls.XDG_CONFIG_DIR
+            or os.environ.get("SWINGMUSIC_XDG_CONFIG_DIR")
+            or os.path.realpath(".")
+        )
 
     @classmethod
     def get_config_folder(cls):

app/setup/sqlite.py

@@ -24,7 +24,7 @@ def setup_sqlite():
     """
     Create Sqlite databases and tables.
     """
-    DbEngine.engine = create_engine(
+    DbEngine._engine = create_engine(
         f"sqlite+pysqlite:///{DbPaths.get_app_db_path()}",
         echo=False,
         max_overflow=20,

main.py

@@ -1,7 +1,8 @@
-import multiprocessing
-import pathlib
-import click
+import os
 import sys
+import click
+import pathlib
+import multiprocessing
 from app.arg_handler import handle_build, handle_password_reset
 from app.utils.filesystem import get_home_res_path
 from app.utils.xdg_utils import get_xdg_config_dir
@@ -66,6 +67,10 @@ def version(*args, **kwargs):
     is_eager=True,
 )
 def run(*args, **kwargs):
+    # INFO: Set the config dir as an environment variable
+    os.environ["SWINGMUSIC_XDG_CONFIG_DIR"] = str(
+        pathlib.Path(kwargs["config"]).resolve()
+    )
     run_app(kwargs["host"], kwargs["port"], kwargs["config"])