X-Git-Url: https://plomlompom.com/repos/feed.xml?a=blobdiff_plain;f=plomtask%2Fdb.py;h=99998a6ab29f760ba0d62f90395739dad4b521ff;hb=c5449a0b00f8865b1129ed56bdd16f1cc055bc87;hp=8e5529062ae18c60a2ed222deb27305f9c18e54c;hpb=3a74c67ef298d16e7a7e5dd030e1fd813f42f0b4;p=plomtask diff --git a/plomtask/db.py b/plomtask/db.py index 8e55290..99998a6 100644 --- a/plomtask/db.py +++ b/plomtask/db.py @@ -1,67 +1,163 @@ """Database management.""" from __future__ import annotations +from os import listdir from os.path import isfile 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 valid_date -PATH_DB_SCHEMA = 'scripts/init.sql' -EXPECTED_DB_VERSION = 0 +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}' -class DatabaseFile: # pylint: disable=too-few-public-methods +class UnmigratedDbException(HandledException): + """To identify case of unmigrated DB file.""" + + +class DatabaseFile: """Represents the sqlite3 database's file.""" + # pylint: disable=too-few-public-methods def __init__(self, path: str) -> None: self.path = path self._check() - def remake(self) -> None: - """Create tables in self.path file as per PATH_DB_SCHEMA sql file.""" - with sql_connect(self.path) as conn: + @classmethod + def create_at(cls, path: str) -> DatabaseFile: + """Make new DB file at path.""" + with sql_connect(path) as conn: with open(PATH_DB_SCHEMA, 'r', encoding='utf-8') as f: conn.executescript(f.read()) - self._check() + conn.execute(f'PRAGMA user_version = {EXPECTED_DB_VERSION}') + return cls(path) + + @classmethod + 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) + migrations_todo = migrations[from_version+1:] + for j, filename in enumerate(migrations_todo): + with sql_connect(path) as conn: + with open(f'{MIGRATIONS_DIR}/{filename}', 'r', + encoding='utf-8') as f: + conn.executescript(f.read()) + user_version = from_version + j + 1 + with sql_connect(path) as conn: + conn.execute(f'PRAGMA user_version = {user_version}') + return cls(path) def _check(self) -> None: """Check file exists, and is of proper DB version and schema.""" - self.exists = isfile(self.path) - if self.exists: - self._validate_user_version() - self._validate_schema() + if not isfile(self.path): + raise NotFoundException + if self._user_version != EXPECTED_DB_VERSION: + raise UnmigratedDbException() + self._validate_schema() + + @staticmethod + def _available_migrations() -> list[str]: + """Validate migrations directory and return sorted entries.""" + msg_too_big = 'Migration directory points beyond expected DB version.' + msg_bad_entry = 'Migration directory contains unexpected entry: ' + msg_missing = 'Migration directory misses migration of number: ' + migrations = {} + for entry in listdir(MIGRATIONS_DIR): + if entry == FILENAME_DB_SCHEMA: + continue + toks = entry.split('_', 1) + if len(toks) < 2: + raise HandledException(msg_bad_entry + entry) + try: + i = int(toks[0]) + except ValueError as e: + raise HandledException(msg_bad_entry + entry) from e + if i > EXPECTED_DB_VERSION: + raise HandledException(msg_too_big) + migrations[i] = toks[1] + migrations_list = [] + for i in range(EXPECTED_DB_VERSION + 1): + if i not in migrations: + raise HandledException(msg_missing + str(i)) + migrations_list += [f'{i}_{migrations[i]}'] + return migrations_list - def _validate_user_version(self) -> None: - """Compare DB user_version with EXPECTED_DB_VERSION.""" + @staticmethod + 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(self.path) as conn: + with sql_connect(path) as conn: db_version = list(conn.execute(sql_for_db_version))[0][0] - if db_version != EXPECTED_DB_VERSION: - msg = f'Wrong DB version, expected '\ - f'{EXPECTED_DB_VERSION}, got {db_version}.' - raise HandledException(msg) + if db_version > EXPECTED_DB_VERSION: + msg = f'Wrong DB version, expected '\ + f'{EXPECTED_DB_VERSION}, got unknown {db_version}.' + raise HandledException(msg) + assert isinstance(db_version, int) + return db_version + + @property + def _user_version(self) -> int: + """Get DB user_version.""" + return self._get_version_of_db(self.path) def _validate_schema(self) -> None: """Compare found schema with what's stored at PATH_DB_SCHEMA.""" + + def reformat_rows(rows: list[str]) -> list[str]: + new_rows = [] + for row in rows: + new_row = [] + for subrow in row.split('\n'): + subrow = subrow.rstrip() + in_parentheses = 0 + split_at = [] + for i, c in enumerate(subrow): + if '(' == c: + in_parentheses += 1 + elif ')' == c: + in_parentheses -= 1 + elif ',' == c and 0 == in_parentheses: + split_at += [i + 1] + prev_split = 0 + for i in split_at: + segment = subrow[prev_split:i].strip() + if len(segment) > 0: + new_row += [f' {segment}'] + prev_split = i + segment = subrow[prev_split:].strip() + if len(segment) > 0: + new_row += [f' {segment}'] + new_row[0] = new_row[0].lstrip() + new_row[-1] = new_row[-1].lstrip() + if new_row[-1] != ')' and new_row[-3][-1] != ',': + new_row[-3] = new_row[-3] + ',' + new_row[-2:] = [' ' + new_row[-1][:-1]] + [')'] + new_rows += ['\n'.join(new_row)] + return new_rows + sql_for_schema = 'SELECT sql FROM sqlite_master ORDER BY sql' msg_err = 'Database has wrong tables schema. Diff:\n' with sql_connect(self.path) as conn: schema_rows = [r[0] for r in conn.execute(sql_for_schema) if r[0]] - retrieved_schema = ';\n'.join(schema_rows) + ';' - with open(PATH_DB_SCHEMA, 'r', encoding='utf-8') as f: - stored_schema = f.read().rstrip() - if stored_schema != retrieved_schema: - diff_msg = Differ().compare(retrieved_schema.splitlines(), - stored_schema.splitlines()) - raise HandledException(msg_err + '\n'.join(diff_msg)) + schema_rows = reformat_rows(schema_rows) + retrieved_schema = ';\n'.join(schema_rows) + ';' + with open(PATH_DB_SCHEMA, 'r', encoding='utf-8') as f: + stored_schema = f.read().rstrip() + if stored_schema != retrieved_schema: + diff_msg = Differ().compare(retrieved_schema.splitlines(), + stored_schema.splitlines()) + raise HandledException(msg_err + '\n'.join(diff_msg)) 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.""" @@ -71,18 +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, - rows: list[list[Any]]) -> None: - """Rewrite relations in table_name to target, with rows values.""" + def rewrite_relations(self, table_name: str, key: str, target: int | str, + 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]: @@ -90,6 +196,17 @@ class DatabaseConnection: return list(self.exec(f'SELECT * FROM {table_name} WHERE {key} = ?', (target,))) + # def column_where_pattern(self, + # table_name: str, + # column: str, + # pattern: str, + # keys: list[str]) -> list[Any]: + # """Return column of rows where one of keys matches pattern.""" + # targets = tuple([f'%{pattern}%'] * len(keys)) + # haystack = ' OR '.join([f'{k} LIKE ?' for k in keys]) + # sql = f'SELECT {column} FROM {table_name} WHERE {haystack}' + # return [row[0] for row in self.exec(sql, targets)] + def column_where(self, table_name: str, column: str, key: str, target: int | str) -> list[Any]: """Return column of table where key == target.""" @@ -107,11 +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]') @@ -121,26 +233,65 @@ class BaseModel(Generic[BaseModelId]): """Template for most of the models we use/derive from the DB.""" table_name = '' to_save: list[str] = [] + to_save_versioned: list[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_ - @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 __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 + return hash(self) == hash(other) + + def __lt__(self, other: Any) -> bool: + if not isinstance(other, self.__class__): + msg = 'cannot compare to object of different class' + raise HandledException(msg) + assert isinstance(self.id_, int) + assert isinstance(other.id_, int) + return self.id_ < other.id_ + + # 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: @@ -155,28 +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 @@ -193,11 +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 @@ -209,7 +383,13 @@ class BaseModel(Generic[BaseModelId]): @classmethod def all(cls: type[BaseModelInstance], db_conn: DatabaseConnection) -> list[BaseModelInstance]: - """Collect all objects of class.""" + """Collect all objects of class into list. + + Note that this primarily returns the contents of the cache, and only + _expands_ that by additional findings in the DB. This assumes the + cache is always instantly cleaned of any items that would be removed + from the DB. + """ items: dict[BaseModelId, BaseModelInstance] = {} for k, v in cls.get_cache().items(): assert isinstance(v, cls) @@ -222,21 +402,56 @@ class BaseModel(Generic[BaseModelId]): items[item.id_] = item return list(items.values()) - def __eq__(self, other: object) -> bool: - if not isinstance(other, self.__class__): - msg = 'cannot compare to object of different class' - raise HandledException(msg) - 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) + @classmethod + def by_date_range_with_limits(cls: type[BaseModelInstance], + db_conn: DatabaseConnection, + date_range: tuple[str, str], + date_col: str = 'day' + ) -> tuple[list[BaseModelInstance], str, + str]: + """Return list of items in database within (open) date_range interval. + + If no range values provided, defaults them to 'yesterday' and + 'tomorrow'. Knows to properly interpret these and 'today' as value. + """ + 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} <= ?' + for row in db_conn.exec(sql, (start_date, end_date)): + items += [cls.by_id(db_conn, row[0])] + return items, start_date, end_date - def save_core(self, db_conn: DatabaseConnection) -> None: - """Write bare-bones self (sans connected items), ensuring self.id_. + @classmethod + def matching(cls: type[BaseModelInstance], db_conn: DatabaseConnection, + pattern: str) -> list[BaseModelInstance]: + """Return all objects whose .to_search match pattern.""" + items = cls.all(db_conn) + if pattern: + filtered = [] + for item in items: + for attr_name in cls.to_search: + toks = attr_name.split('.') + parent = item + for tok in toks: + attr = getattr(parent, tok) + parent = attr + if pattern in attr: + filtered += [item] + break + return filtered + return items + + # database writing + + def save(self, db_conn: DatabaseConnection) -> None: + """Write self to DB and cache and ensure .id_. Write both to DB, and to cache. To DB, write .id_ and attributes - listed in cls.to_save. + listed in cls.to_save[_versioned|_relations]. Ensure self.id_ by setting it to what the DB command returns as the last saved row's ID (cursor.lastrowid), EXCEPT if self.id_ already @@ -245,16 +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, 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)], key_index) def remove(self, db_conn: DatabaseConnection) -> None: - """Remove from DB.""" - assert isinstance(self.id_, int | str) - self.uncache() + """Remove from DB and cache, including dependencies.""" + 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: + db_conn.delete_where(table, column, self.id_) + self._uncache() db_conn.delete_where(self.table_name, 'id', self.id_) + self._disappear()