X-Git-Url: https://plomlompom.com/repos/feed.xml?a=blobdiff_plain;f=plomtask%2Fdb.py;h=99998a6ab29f760ba0d62f90395739dad4b521ff;hb=c5449a0b00f8865b1129ed56bdd16f1cc055bc87;hp=4396b444a61f0c2f59e2046b554e79c56e541faa;hpb=f92de64d072009c8c4bf96b9eeb9fa245045662b;p=plomtask diff --git a/plomtask/db.py b/plomtask/db.py index 4396b44..99998a6 100644 --- a/plomtask/db.py +++ b/plomtask/db.py @@ -6,9 +6,9 @@ from difflib import Differ from sqlite3 import connect as sql_connect, Cursor, Row from typing import Any, Self, TypeVar, Generic from plomtask.exceptions import HandledException, NotFoundException -from plomtask.dating import (MIN_RANGE_DATE, MAX_RANGE_DATE, valid_date) +from plomtask.dating import valid_date -EXPECTED_DB_VERSION = 4 +EXPECTED_DB_VERSION = 5 MIGRATIONS_DIR = 'migrations' FILENAME_DB_SCHEMA = f'init_{EXPECTED_DB_VERSION}.sql' PATH_DB_SCHEMA = f'{MIGRATIONS_DIR}/{FILENAME_DB_SCHEMA}' @@ -18,8 +18,9 @@ class UnmigratedDbException(HandledException): """To identify case of unmigrated DB file.""" -class DatabaseFile: # pylint: disable=too-few-public-methods +class DatabaseFile: """Represents the sqlite3 database's file.""" + # pylint: disable=too-few-public-methods def __init__(self, path: str) -> None: self.path = path @@ -38,7 +39,7 @@ class DatabaseFile: # pylint: disable=too-few-public-methods def migrate(cls, path: str) -> DatabaseFile: """Apply migrations from_version to EXPECTED_DB_VERSION.""" migrations = cls._available_migrations() - from_version = cls.get_version_of_db(path) + from_version = cls._get_version_of_db(path) migrations_todo = migrations[from_version+1:] for j, filename in enumerate(migrations_todo): with sql_connect(path) as conn: @@ -54,7 +55,7 @@ class DatabaseFile: # pylint: disable=too-few-public-methods """Check file exists, and is of proper DB version and schema.""" if not isfile(self.path): raise NotFoundException - if self.user_version != EXPECTED_DB_VERSION: + if self._user_version != EXPECTED_DB_VERSION: raise UnmigratedDbException() self._validate_schema() @@ -86,7 +87,7 @@ class DatabaseFile: # pylint: disable=too-few-public-methods return migrations_list @staticmethod - def get_version_of_db(path: str) -> int: + def _get_version_of_db(path: str) -> int: """Get DB user_version, fail if outside expected range.""" sql_for_db_version = 'PRAGMA user_version' with sql_connect(path) as conn: @@ -99,9 +100,9 @@ class DatabaseFile: # pylint: disable=too-few-public-methods return db_version @property - def user_version(self) -> int: + def _user_version(self) -> int: """Get DB user_version.""" - return self.__class__.get_version_of_db(self.path) + return self._get_version_of_db(self.path) def _validate_schema(self) -> None: """Compare found schema with what's stored at PATH_DB_SCHEMA.""" @@ -156,8 +157,7 @@ class DatabaseConnection: """A single connection to the database.""" def __init__(self, db_file: DatabaseFile) -> None: - self.file = db_file - self.conn = sql_connect(self.file.path) + self.conn = sql_connect(db_file.path) def commit(self) -> None: """Commit SQL transaction.""" @@ -167,18 +167,28 @@ class DatabaseConnection: """Add commands to SQL transaction.""" return self.conn.execute(code, inputs) + def exec_on_vals(self, code: str, inputs: tuple[Any, ...]) -> Cursor: + """Wrapper around .exec appending adequate " (?, …)" to code.""" + q_marks_from_values = '(' + ','.join(['?'] * len(inputs)) + ')' + return self.exec(f'{code} {q_marks_from_values}', inputs) + def close(self) -> None: """Close DB connection.""" self.conn.close() def rewrite_relations(self, table_name: str, key: str, target: int | str, - rows: list[list[Any]]) -> None: - """Rewrite relations in table_name to target, with rows values.""" + rows: list[list[Any]], key_index: int = 0) -> None: + # pylint: disable=too-many-arguments + """Rewrite relations in table_name to target, with rows values. + + Note that single rows are expected without the column and value + identified by key and target, which are inserted inside the function + at key_index. + """ self.delete_where(table_name, key, target) for row in rows: - values = tuple([target] + row) - q_marks = self.__class__.q_marks_from_values(values) - self.exec(f'INSERT INTO {table_name} VALUES {q_marks}', values) + values = tuple(row[:key_index] + [target] + row[key_index:]) + self.exec_on_vals(f'INSERT INTO {table_name} VALUES', values) def row_where(self, table_name: str, key: str, target: int | str) -> list[Row]: @@ -214,11 +224,6 @@ class DatabaseConnection: """Delete from table where key == target.""" self.exec(f'DELETE FROM {table_name} WHERE {key} = ?', (target,)) - @staticmethod - def q_marks_from_values(values: tuple[Any]) -> str: - """Return placeholder to insert values into SQL code.""" - return '(' + ','.join(['?'] * len(values)) + ')' - BaseModelId = TypeVar('BaseModelId', int, str) BaseModelInstance = TypeVar('BaseModelInstance', bound='BaseModel[Any]') @@ -229,25 +234,34 @@ class BaseModel(Generic[BaseModelId]): table_name = '' to_save: list[str] = [] to_save_versioned: list[str] = [] - to_save_relations: list[tuple[str, str, str]] = [] + to_save_relations: list[tuple[str, str, str, int]] = [] id_: None | BaseModelId cache_: dict[BaseModelId, Self] to_search: list[str] = [] + _exists = True def __init__(self, id_: BaseModelId | None) -> None: if isinstance(id_, int) and id_ < 1: msg = f'illegal {self.__class__.__name__} ID, must be >=1: {id_}' raise HandledException(msg) + if isinstance(id_, str) and "" == id_: + msg = f'illegal {self.__class__.__name__} ID, must be non-empty' + raise HandledException(msg) self.id_ = id_ + def __hash__(self) -> int: + hashable = [self.id_] + [getattr(self, name) for name in self.to_save] + for definition in self.to_save_relations: + attr = getattr(self, definition[2]) + hashable += [tuple(rel.id_ for rel in attr)] + for name in self.to_save_versioned: + hashable += [hash(getattr(self, name))] + return hash(tuple(hashable)) + def __eq__(self, other: object) -> bool: if not isinstance(other, self.__class__): return False - to_hash_me = tuple([self.id_] + - [getattr(self, name) for name in self.to_save]) - to_hash_other = tuple([other.id_] + - [getattr(other, name) for name in other.to_save]) - return hash(to_hash_me) == hash(to_hash_other) + return hash(self) == hash(other) def __lt__(self, other: Any) -> bool: if not isinstance(other, self.__class__): @@ -257,17 +271,27 @@ class BaseModel(Generic[BaseModelId]): assert isinstance(other.id_, int) return self.id_ < other.id_ - @classmethod - def get_cached(cls: type[BaseModelInstance], - id_: BaseModelId) -> BaseModelInstance | None: - """Get object of id_ from class's cache, or None if not found.""" - # pylint: disable=consider-iterating-dictionary - cache = cls.get_cache() - if id_ in cache.keys(): - obj = cache[id_] - assert isinstance(obj, cls) - return obj - return None + # cache management + # (we primarily use the cache to ensure we work on the same object in + # memory no matter where and how we retrieve it, e.g. we don't want + # .by_id() calls to create a new object each time, but rather a pointer + # to the one already instantiated) + + def __getattribute__(self, name: str) -> Any: + """Ensure fail if ._disappear() was called, except to check ._exists""" + if name != '_exists' and not super().__getattribute__('_exists'): + raise HandledException('Object does not exist.') + return super().__getattribute__(name) + + def _disappear(self) -> None: + """Invalidate object, make future use raise exceptions.""" + assert self.id_ is not None + if self._get_cached(self.id_): + self._uncache() + to_kill = list(self.__dict__.keys()) + for attr in to_kill: + delattr(self, attr) + self._exists = False @classmethod def empty_cache(cls) -> None: @@ -282,28 +306,52 @@ class BaseModel(Generic[BaseModelId]): cls.cache_ = d return cls.cache_ - def cache(self) -> None: - """Update object in class's cache.""" + @classmethod + def _get_cached(cls: type[BaseModelInstance], + id_: BaseModelId) -> BaseModelInstance | None: + """Get object of id_ from class's cache, or None if not found.""" + # pylint: disable=consider-iterating-dictionary + cache = cls.get_cache() + if id_ in cache.keys(): + obj = cache[id_] + assert isinstance(obj, cls) + return obj + return None + + def _cache(self) -> None: + """Update object in class's cache. + + Also calls ._disappear if cache holds older reference to object of same + ID, but different memory address, to avoid doing anything with + dangling leftovers. + """ if self.id_ is None: raise HandledException('Cannot cache object without ID.') - cache = self.__class__.get_cache() + cache = self.get_cache() + old_cached = self._get_cached(self.id_) + if old_cached and id(old_cached) != id(self): + # pylint: disable=protected-access + # (cause we remain within the class) + old_cached._disappear() cache[self.id_] = self - def uncache(self) -> None: + def _uncache(self) -> None: """Remove self from cache.""" if self.id_ is None: raise HandledException('Cannot un-cache object without ID.') - cache = self.__class__.get_cache() + cache = self.get_cache() del cache[self.id_] + # object retrieval and generation + @classmethod def from_table_row(cls: type[BaseModelInstance], # pylint: disable=unused-argument db_conn: DatabaseConnection, row: Row | list[Any]) -> BaseModelInstance: - """Make from DB row, write to DB cache.""" + """Make from DB row, update DB cache with it.""" obj = cls(*row) - obj.cache() + obj._cache() return obj @classmethod @@ -320,11 +368,10 @@ class BaseModel(Generic[BaseModelId]): """ obj = None if id_ is not None: - obj = cls.get_cached(id_) + obj = cls._get_cached(id_) if not obj: for row in db_conn.row_where(cls.table_name, 'id', id_): obj = cls.from_table_row(db_conn, row) - obj.cache() break if obj: return obj @@ -358,19 +405,19 @@ class BaseModel(Generic[BaseModelId]): @classmethod def by_date_range_with_limits(cls: type[BaseModelInstance], db_conn: DatabaseConnection, - date_range: tuple[str, str] = ('', ''), + date_range: tuple[str, str], date_col: str = 'day' ) -> tuple[list[BaseModelInstance], str, str]: - """Return list of Days in database within (open) date_range interval. + """Return list of items in database within (open) date_range interval. - If no range values provided, defaults them to MIN_RANGE_DATE and - MAX_RANGE_DATE. Also knows to properly interpret 'today' as value. + If no range values provided, defaults them to 'yesterday' and + 'tomorrow'. Knows to properly interpret these and 'today' as value. """ - min_date = MIN_RANGE_DATE - max_date = MAX_RANGE_DATE - start_date = valid_date(date_range[0] if date_range[0] else min_date) - end_date = valid_date(date_range[1] if date_range[1] else max_date) + start_str = date_range[0] if date_range[0] else 'yesterday' + end_str = date_range[1] if date_range[1] else 'tomorrow' + start_date = valid_date(start_str) + end_date = valid_date(end_str) items = [] sql = f'SELECT id FROM {cls.table_name} ' sql += f'WHERE {date_col} >= ? AND {date_col} <= ?' @@ -398,6 +445,8 @@ class BaseModel(Generic[BaseModelId]): return filtered return items + # database writing + def save(self, db_conn: DatabaseConnection) -> None: """Write self to DB and cache and ensure .id_. @@ -411,28 +460,28 @@ class BaseModel(Generic[BaseModelId]): """ values = tuple([self.id_] + [getattr(self, key) for key in self.to_save]) - q_marks = DatabaseConnection.q_marks_from_values(values) table_name = self.table_name - cursor = db_conn.exec(f'REPLACE INTO {table_name} VALUES {q_marks}', - values) + cursor = db_conn.exec_on_vals(f'REPLACE INTO {table_name} VALUES', + values) if not isinstance(self.id_, str): self.id_ = cursor.lastrowid # type: ignore[assignment] - self.cache() + self._cache() for attr_name in self.to_save_versioned: getattr(self, attr_name).save(db_conn) - for table, column, attr_name in self.to_save_relations: + for table, column, attr_name, key_index in self.to_save_relations: assert isinstance(self.id_, (int, str)) db_conn.rewrite_relations(table, column, self.id_, [[i.id_] for i - in getattr(self, attr_name)]) + in getattr(self, attr_name)], key_index) def remove(self, db_conn: DatabaseConnection) -> None: """Remove from DB and cache, including dependencies.""" - if self.id_ is None or self.__class__.get_cached(self.id_) is None: + if self.id_ is None or self._get_cached(self.id_) is None: raise HandledException('cannot remove unsaved item') for attr_name in self.to_save_versioned: getattr(self, attr_name).remove(db_conn) - for table, column, attr_name in self.to_save_relations: + for table, column, attr_name, _ in self.to_save_relations: db_conn.delete_where(table, column, self.id_) - self.uncache() + self._uncache() db_conn.delete_where(self.table_name, 'id', self.id_) + self._disappear()