feat(v2): add validated runtime and metadata store

backend/alembic/env.py

@@ -0,0 +1,61 @@
+from __future__ import annotations
+
+import importlib
+import os
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import create_engine, pool
+from sqlalchemy.engine import URL, make_url
+
+Base = importlib.import_module("backup_tool.db.models").Base
+
+config = context.config
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+target_metadata = Base.metadata
+
+
+def configured_url() -> str:
+    raw_url = os.environ.get("BACKUP_TOOL_DATABASE_URL") or config.get_main_option("sqlalchemy.url")
+    if raw_url is None:
+        raise RuntimeError("sqlalchemy.url is required")
+    return raw_url
+
+
+def synchronous_url(raw_url: str) -> URL:
+    url = make_url(raw_url)
+    if url.drivername != "sqlite+aiosqlite":
+        raise RuntimeError("v2 migrations require sqlite+aiosqlite")
+    return url.set(drivername="sqlite")
+
+
+def run_migrations_offline() -> None:
+    url = synchronous_url(configured_url())
+    context.configure(
+        url=url.render_as_string(hide_password=False),
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+        compare_type=True,
+    )
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    engine = create_engine(
+        synchronous_url(configured_url()),
+        poolclass=pool.NullPool,
+    )
+    with engine.connect() as connection:
+        context.configure(connection=connection, target_metadata=target_metadata, compare_type=True)
+        with context.begin_transaction():
+            context.run_migrations()
+    engine.dispose()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()