plomlompom.com Git - plomtask/blob - plomtask/db.py

   1 """Database management."""
   2 from os.path import isfile
   3 from difflib import Differ
   4 from sqlite3 import connect as sql_connect, Cursor
   5 from typing import Any
   6 from plomtask.exceptions import HandledException
   7
   8 PATH_DB_SCHEMA = 'scripts/init.sql'
   9
  10
  11 class DatabaseFile:  # pylint: disable=too-few-public-methods
  12     """Represents the sqlite3 database's file."""
  13
  14     def __init__(self, path: str) -> None:
  15         self.path = path
  16         self._check()
  17
  18     def remake(self) -> None:
  19         """Create tables in self.path file as per PATH_DB_SCHEMA sql file."""
  20         with sql_connect(self.path) as conn:
  21             with open(PATH_DB_SCHEMA, 'r', encoding='utf-8') as f:
  22                 conn.executescript(f.read())
  23         self._check()
  24
  25     def _check(self) -> None:
  26         """Check file exists and is of proper schema."""
  27         self.exists = isfile(self.path)
  28         if self.exists:
  29             self._validate_schema()
  30
  31     def _validate_schema(self) -> None:
  32         """Compare found schema with what's stored at PATH_DB_SCHEMA."""
  33         sql_for_schema = 'SELECT sql FROM sqlite_master ORDER BY sql'
  34         msg_err = 'Database has wrong tables schema. Diff:\n'
  35         with sql_connect(self.path) as conn:
  36             schema_rows = [r[0] for r in conn.execute(sql_for_schema) if r[0]]
  37             retrieved_schema = ';\n'.join(schema_rows) + ';'
  38             with open(PATH_DB_SCHEMA, 'r', encoding='utf-8') as f:
  39                 stored_schema = f.read().rstrip()
  40                 if stored_schema != retrieved_schema:
  41                     diff_msg = Differ().compare(retrieved_schema.splitlines(),
  42                                                 stored_schema.splitlines())
  43                     raise HandledException(msg_err + '\n'.join(diff_msg))
  44
  45
  46 class DatabaseConnection:
  47     """A single connection to the database."""
  48
  49     def __init__(self, db_file: DatabaseFile) -> None:
  50         self.file = db_file
  51         self.conn = sql_connect(self.file.path)
  52
  53     def commit(self) -> None:
  54         """Commit SQL transaction."""
  55         self.conn.commit()
  56
  57     def exec(self, code: str, inputs: tuple[Any, ...] = tuple()) -> Cursor:
  58         """Add commands to SQL transaction."""
  59         return self.conn.execute(code, inputs)
  60
  61     def close(self) -> None:
  62         """Close DB connection."""
  63         self.conn.close()