Init project

birthday_pool_bot/repositories/migrations/migrator.py

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+import importlib.util
+import pathlib
+from types import ModuleType
+from typing import Generator, Iterable
+
+from alembic import command as alembic_command
+from alembic.config import Config as AlembicConfig
+
+from birthday_pool_bot.repositories import RepositorySettings
+
+
+class Migrator:
+    MIGRATION_FILENAME_TEMPLATE = (
+        "%%(year)d_%%(month)02d_%%(day)02d_%%(hour)02dh%%(minute)02dm%%(second)02ds_%%(slug)s"
+    )
+
+    def __init__(self, settings: RepositorySettings):
+        self._settings = settings
+
+        self._alembic_config = self._generate_alembic_config()
+
+    def _generate_alembic_config(self) -> AlembicConfig:
+        migrations_path = self.get_migrations_directory_path()
+
+        config = AlembicConfig()
+        config.set_main_option("script_location", str(migrations_path))
+        config.set_main_option("file_template", self.MIGRATION_FILENAME_TEMPLATE)
+        config.set_main_option("sqlalchemy.url", str(self._settings.dsn).replace("%", "%%"))
+
+        return config
+
+    def squash_migrations(
+            self,
+            new_migration_id: str | None = None,
+            **kwargs,
+    ) -> str:
+        new_message = kwargs.get("new_message", None)
+
+        if new_migration_id is None:
+            last_migration_id = self.get_latest_migration()
+            new_migration_id = last_migration_id
+
+        self.rollback(migration_id="base")
+        self._delete_all_migrations()
+        new_migration_id = self.create_migration(
+            migration_id=new_migration_id,
+            message=new_message,
+        )
+        return new_migration_id
+
+    def migrate(self, migration_id: str | None = None, **kwargs) -> str | None:
+        alembic_revision = migration_id or "head"
+        alembic_command.upgrade(config=self._alembic_config, revision=alembic_revision)
+
+        return self.get_current_migration()
+
+    def rollback(self, migration_id: str | None = None, **kwargs) -> str | None:
+        alembic_revision = migration_id or "-1"
+        alembic_command.downgrade(config=self._alembic_config, revision=alembic_revision)
+
+        return self.get_current_migration()
+
+    def get_current_migration(self) -> str | None:
+        return None
+
+    def create_migration(
+            self,
+            migration_id: str | None = None,
+            **kwargs,
+    ) -> str:
+        message = kwargs.get("message", None)
+
+        alembic_command.revision(
+            self._alembic_config,
+            message=message,
+            rev_id=migration_id,
+            autogenerate=True,
+        )
+
+        last_migration_id = self.get_latest_migration()
+        if last_migration_id is None:
+            raise RuntimeError("Migration not created")
+
+        return last_migration_id
+
+    def get_latest_migration(self) -> str | None:
+        last_migration_id = None
+        for migration_id in self.get_migrations():
+            last_migration_id = migration_id
+        return last_migration_id
+
+    def get_migrations(self) -> Generator[str, None, None]:
+        migrations_modules = self._get_migrations_modules()
+        sorted_migrations_modules = self._sort_migrations_modules(modules=migrations_modules)
+        for migration_module in sorted_migrations_modules:
+            yield migration_module.revision
+
+    def _get_migrations_modules(self) -> Iterable[ModuleType]:
+        migrations_path = self.get_migrations_directory_path()
+        versions_path = migrations_path / "versions"
+
+        for index, migration_module_path in enumerate(versions_path.glob("*.py")):
+            migration_module_name = f"migration_{index:08}"
+            migration_module_spec = importlib.util.spec_from_file_location(
+                name=migration_module_name,
+                location=migration_module_path,
+            )
+            if migration_module_spec is None or migration_module_spec.loader is None:
+                raise ValueError(f"Cannot load migration module '{migration_module_path}'")
+            migration_module = importlib.util.module_from_spec(spec=migration_module_spec)
+            migration_module_spec.loader.exec_module(migration_module)
+            yield migration_module
+
+    def _sort_migrations_modules(self, modules: Iterable[ModuleType]) -> list[ModuleType]:
+        next_module_map = {}
+        first_module = None
+        for module in modules:
+            if module.down_revision is None:
+                if first_module is not None:
+                    raise ValueError((
+                        "Found multiple first migrations: "
+                        f"'{module.revision}' and '{first_module.revision}'"
+                    ))
+                first_module = module
+            else:
+                next_module_map[module.down_revision] = module
+        if first_module is None:
+            raise ValueError("Doesn't found first migration")
+
+        current_module = first_module
+        sorted_modules = [current_module]
+        while next_module_map:
+            current_module = next_module_map.pop(current_module.revision)
+            sorted_modules.append(current_module)
+
+        return sorted_modules
+
+    def _delete_all_migrations(self):
+        migrations_path = self.get_migrations_directory_path()
+        versions_path = migrations_path / "versions"
+        for migration_file_path in versions_path.glob("*.py"):
+            migration_file_path.unlink()
+
+    def get_migrations_directory_path(self) -> pathlib.Path:
+        directory_path = pathlib.Path(__file__).parent
+        return directory_path