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
   5 from plomtask.misc import HandledException
   6
   7 PATH_DB_SCHEMA = 'scripts/init.sql'
   8
   9
  10 class DatabaseFile:
  11     """Represents the sqlite3 database's file."""
  12
  13     def __init__(self, path):
  14         self.path = path
  15         self.check()
  16
  17     def check(self):
  18         """Check file exists and is of proper schema."""
  19         self.exists = isfile(self.path)
  20         if self.exists:
  21             self.validate_schema()
  22
  23     def remake(self):
  24         """Create tables in self.path file as per PATH_DB_SCHEMA sql file."""
  25         with sql_connect(self.path) as conn:
  26             with open(PATH_DB_SCHEMA, 'r', encoding='utf-8') as f:
  27                 conn.executescript(f.read())
  28         self.check()
  29
  30     def validate_schema(self):
  31         """Compare found schema with what's stored at PATH_DB_SCHEMA."""
  32         sql_for_schema = 'SELECT sql FROM sqlite_master ORDER BY sql'
  33         msg_err = 'Database has wrong tables schema. Diff:\n'
  34         with sql_connect(self.path) as conn:
  35             schema_rows = [r[0] for r in conn.execute(sql_for_schema) if r[0]]
  36             retrieved_schema = ';\n'.join(schema_rows) + ';'
  37             with open(PATH_DB_SCHEMA, 'r', encoding='utf-8') as f:
  38                 stored_schema = f.read().rstrip()
  39                 if stored_schema != retrieved_schema:
  40                     diff_msg = Differ().compare(retrieved_schema.splitlines(),
  41                                                 stored_schema.splitlines())
  42                     raise HandledException(msg_err + '\n'.join(diff_msg))