replace migration system with db erasure

conftest.py

@@ -1,14 +1,14 @@
+import hashlib
 import logging
 import sqlite3
 from collections.abc import Iterator
 from pathlib import Path
 
 import _pytest.pathlib
 import pytest
-import yoyo
 from click.testing import CliRunner
 
-from rose.foundation.conf import MIGRATIONS_PATH, Config
+from rose.foundation.conf import SCHEMA_PATH, Config
 
 logger = logging.getLogger(__name__)
 
@@ -25,10 +25,13 @@ def config(isolated_dir: Path) -> Config:
     cache_dir.mkdir()
     cache_database_path = cache_dir / "cache.sqlite3"
 
-    db_backend = yoyo.get_backend(f"sqlite:///{cache_database_path}")
-    db_migrations = yoyo.read_migrations(str(MIGRATIONS_PATH))
-    with db_backend.lock():
-        db_backend.apply_migrations(db_backend.to_apply(db_migrations))
+    with sqlite3.connect(cache_database_path) as conn:
+        with SCHEMA_PATH.open("r") as fp:
+            conn.executescript(fp.read())
+        conn.execute("CREATE TABLE _schema_hash (value TEXT PRIMARY KEY)")
+        with SCHEMA_PATH.open("rb") as fp:
+            latest_schema_hash = hashlib.sha256(fp.read()).hexdigest()
+        conn.execute("INSERT INTO _schema_hash (value) VALUES (?)", (latest_schema_hash,))
 
     return Config(
         music_source_dir=isolated_dir / "source",

flake.nix

@@ -31,7 +31,6 @@
         fuse
         mutagen
         uuid6-python
-        yoyo-migrations
       ];
       dev-deps = with python.pkgs; [
         black

pyproject.toml

@@ -59,9 +59,6 @@ strict = true
 strict_optional = true
 explicit_package_bases = true
 
-[[tool.mypy.overrides]]
-module = "yoyo"
-ignore_missing_imports = true
 [[tool.mypy.overrides]]
 module = "fuse"
 ignore_missing_imports = true

rose/cache/database.py

@@ -1,14 +1,13 @@
 import binascii
+import hashlib
 import logging
 import random
 import sqlite3
 import time
 from collections.abc import Iterator
 from contextlib import contextmanager
 
-import yoyo
-
-from rose.foundation.conf import MIGRATIONS_PATH, Config
+from rose.foundation.conf import SCHEMA_PATH, Config
 
 logger = logging.getLogger(__name__)
 
@@ -72,9 +71,34 @@ def connect_fn(c: Config) -> sqlite3.Connection:
 
 
 def migrate_database(c: Config) -> None:
-    db_backend = yoyo.get_backend(f"sqlite:///{c.cache_database_path}")
-    db_migrations = yoyo.read_migrations(str(MIGRATIONS_PATH))
+    """
+    "Migrate" the database. If the schema in the database does not match that on disk, then nuke the
+    database and recreate it from scratch. Otherwise, no op.
 
-    logger.debug("Applying database migrations")
-    with db_backend.lock():
-        db_backend.apply_migrations(db_backend.to_apply(db_migrations))
+    We can do this because the database is just a read cache. It is not source-of-truth for any of
+    its own data.
+    """
+    with SCHEMA_PATH.open("rb") as fp:
+        latest_schema_hash = hashlib.sha256(fp.read()).hexdigest()
+
+    with connect(c) as conn:
+        cursor = conn.execute(
+            """
+            SELECT EXISTS(
+                SELECT * FROM sqlite_master
+                WHERE type = 'table' AND name = '_schema_hash'
+            )
+            """
+        )
+        if cursor.fetchone()[0]:
+            cursor = conn.execute("SELECT value FROM _schema_hash")
+            if (row := cursor.fetchone()) and row[0] == latest_schema_hash:
+                # Everything matches! Exit!
+                return
+
+    c.cache_database_path.unlink(missing_ok=True)
+    with connect(c) as conn:
+        with SCHEMA_PATH.open("r") as fp:
+            conn.executescript(fp.read())
+        conn.execute("CREATE TABLE _schema_hash (value TEXT PRIMARY KEY)")
+        conn.execute("INSERT INTO _schema_hash (value) VALUES (?)", (latest_schema_hash,))

rose/cache/database_test.py

@@ -1,34 +1,31 @@
-import sqlite3
-from pathlib import Path
+import hashlib
 
-import yoyo
+from rose.cache.database import connect, migrate_database
+from rose.foundation.conf import SCHEMA_PATH, Config
 
-from conftest import freeze_database_time
-from rose.cache.database import migrate_database
-from rose.foundation.conf import MIGRATIONS_PATH, Config
 
-
-def test_run_database_migrations(config: Config) -> None:
+def test_schema(config: Config) -> None:
+    # Test that the schema successfully bootstraps.
+    with SCHEMA_PATH.open("rb") as fp:
+        latest_schema_hash = hashlib.sha256(fp.read()).hexdigest()
     migrate_database(config)
-    assert config.cache_database_path.exists()
-
-    with sqlite3.connect(str(config.cache_database_path)) as conn:
-        freeze_database_time(conn)
-        cursor = conn.execute("SELECT 1 FROM _yoyo_version")
-        assert len(cursor.fetchall()) > 0
+    with connect(config) as conn:
+        cursor = conn.execute("SELECT value FROM _schema_hash")
+        assert cursor.fetchone()[0] == latest_schema_hash
 
 
-def test_migrations(isolated_dir: Path) -> None:
-    """
-    Test that, for each migration, the up -> down -> up path doesn't
-    cause an error. Basically, ladder our way up through the migration
-    chain.
-    """
-    backend = yoyo.get_backend(f"sqlite:///{isolated_dir / 'db.sqlite3'}")
-    migrations = yoyo.read_migrations(str(MIGRATIONS_PATH))
+def test_migration(config: Config) -> None:
+    # Test that "migrating" the database correctly migrates it.
+    config.cache_database_path.unlink()
+    with connect(config) as conn:
+        conn.execute("CREATE TABLE _schema_hash (value TEXT PRIMARY KEY)")
+        conn.execute("INSERT INTO _schema_hash (value) VALUES ('haha')")
 
-    assert len(migrations) > 0
-    for mig in migrations:
-        backend.apply_one(mig)
-        backend.rollback_one(mig)
-        backend.apply_one(mig)
+    with SCHEMA_PATH.open("rb") as fp:
+        latest_schema_hash = hashlib.sha256(fp.read()).hexdigest()
+    migrate_database(config)
+    with connect(config) as conn:
+        cursor = conn.execute("SELECT value FROM _schema_hash")
+        assert cursor.fetchone()[0] == latest_schema_hash
+        cursor = conn.execute("SELECT COUNT(*) FROM _schema_hash")
+        assert cursor.fetchone()[0] == 1

migrations/20231009_01_qlEHa-bootstrap.sql → rose/cache/schema.sql

@@ -1,6 +1,3 @@
--- bootstrap
--- depends: 
-
 CREATE TABLE release_type_enum (value TEXT PRIMARY KEY);
 INSERT INTO release_type_enum (value) VALUES
     ('album'),

rose/foundation/conf.py

@@ -13,7 +13,7 @@
 XDG_CACHE_HOME = Path(os.environ.get("XDG_CACHE_HOME", os.environ["HOME"] + "/.cache"))
 CACHE_PATH = XDG_CACHE_HOME / "rose"
 
-MIGRATIONS_PATH = Path(__file__).resolve().parent.parent.parent / "migrations"
+SCHEMA_PATH = Path(__file__).resolve().parent.parent / "cache" / "schema.sql"
 
 
 class ConfigNotFoundError(RoseError):

setup.py

@@ -14,6 +14,5 @@
         "fuse-python",
         "mutagen",
         "uuid6-python",
-        "yoyo-migrations",
     ],
 )