py.lib

Yohn Y. 2020-12-25 Child:10227cc154fa

py.lib/db/migrator.py

+ Добавления инструмента миграций

awgur@16	1 # coding: utf-8
awgur@16	2 """\
awgur@16	3 Инструмент миграции схемы БД.
awgur@16	4
awgur@16	5 DOC: https://ws.a0fs.net/w/ncc.ws/devel/python/modules/db_migrator/
awgur@16	6 """
awgur@16	7
awgur@16	8 from os.path import exists, join as p_join, isdir
awgur@16	9 from os import listdir
awgur@16	10
awgur@16	11
awgur@16	12 class MigrateError(Exception): pass
awgur@16	13
awgur@16	14
awgur@16	15 class MigrateManager(object):
awgur@16	16 def __init__(self, control_table: str, migrate_env: str):
awgur@16	17 self.control_table = control_table
awgur@16	18
awgur@16	19 if not exists(migrate_env):
awgur@16	20 raise MigrateError('Migrate enviroment not found')
awgur@16	21
awgur@16	22 self.schema = p_join(migrate_env, 'schema.sql')
awgur@16	23 if not exists(self.schema):
awgur@16	24 raise MigrateError('Schema file not found: %s' % self.schema)
awgur@16	25
awgur@16	26 self.patch_dir = p_join(migrate_env, 'patch')
awgur@16	27 if not isdir(self.patch_dir):
awgur@16	28 raise MigrateError('Patch dir not found or not directory: %s' % self.patch_dir)
awgur@16	29
awgur@16	30 def get_patch_files(self, ver: int):
awgur@16	31 res = {}
awgur@16	32 for f in listdir(self.patch_dir):
awgur@16	33 if not f.lower().endswith('.sql'):
awgur@16	34 continue
awgur@16	35
awgur@16	36 _f = f.strip().split('.')
awgur@16	37
awgur@16	38 try:
awgur@16	39 _ver = int(_f[0])
awgur@16	40
awgur@16	41 except (TypeError, ValueError) as e:
awgur@16	42 raise MigrateError('Error on parse version "%(ver)s" of file "%(f)s": %(e)s' % {
awgur@16	43 'ver': _f[0],
awgur@16	44 'f': f,
awgur@16	45 'e': e,
awgur@16	46 })
awgur@16	47
awgur@16	48 except IndexError:
awgur@16	49 raise MigrateError('Error on get version from filename: %s' % f)
awgur@16	50
awgur@16	51 if _ver in res:
awgur@16	52 raise MigrateError('Version duplicates on parse file: %s' % f)
awgur@16	53
awgur@16	54 res[_ver] = p_join(self.patch_dir, f)
awgur@16	55
awgur@16	56 for i in sorted(res.keys()):
awgur@16	57 if i > ver:
awgur@16	58 yield i, res[i]
awgur@16	59
awgur@16	60 @staticmethod
awgur@16	61 def get_commands(file):
awgur@16	62 buf = []
awgur@16	63 with open(file) as IN:
awgur@16	64 for l in IN:
awgur@16	65 if l.lstrip().startswith('--'):
awgur@16	66 if buf:
awgur@16	67 yield '\n'.join(buf)
awgur@16	68 buf[:] = []
awgur@16	69
awgur@16	70 else:
awgur@16	71 buf.append(l)
awgur@16	72
awgur@16	73 if buf:
awgur@16	74 yield '\n'.join(buf)
awgur@16	75
awgur@16	76 def init_db(self, db):
awgur@16	77 cursor = db.cursor()
awgur@16	78 for c in self.get_commands(self.schema):
awgur@16	79 cursor.execute(c)
awgur@16	80 db.commit()
awgur@16	81
awgur@16	82 db.commit()
awgur@16	83
awgur@16	84 def check(self, db):
awgur@16	85 cursor = db.cursor()
awgur@16	86 cursor.execute("SELECT version FROM %s" % self.control_table)
awgur@16	87 q = cursor.fetchone()
awgur@16	88 del cursor
awgur@16	89
awgur@16	90 if q is None:
awgur@16	91 ver = -1
awgur@16	92 else:
awgur@16	93 ver = int(q[0])
awgur@16	94
awgur@16	95 new_ver = ver
awgur@16	96 cursor = db.cursor()
awgur@16	97 for up_ver, patch_file in self.get_patch_files(ver):
awgur@16	98 new_ver = up_ver
awgur@16	99 for cmd in self.get_commands(patch_file):
awgur@16	100 cursor.execute(cmd)
awgur@16	101 db.commit()
awgur@16	102
awgur@16	103 cursor.execute("""
awgur@16	104 UPDATE %s
awgur@16	105 SET version = %s
awgur@16	106 """ % (self.control_table, new_ver))
awgur@16	107
awgur@16	108