osm_common/dbbase.py

   1 # -*- coding: utf-8 -*-
   2
   3 # Copyright 2018 Telefonica S.A.
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #    http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  14 # implied.
  15 # See the License for the specific language governing permissions and
  16 # limitations under the License.
  17
  18 import yaml
  19 import logging
  20 from http import HTTPStatus
  21 from copy import deepcopy
  22 from Crypto.Cipher import AES
  23 from base64 import b64decode, b64encode
  24 from osm_common.common_utils import FakeLock
  25 from threading import Lock
  26
  27 __author__ = "Alfonso Tierno <alfonso.tiernosepulveda@telefonica.com>"
  28
  29
  30 class DbException(Exception):
  31
  32     def __init__(self, message, http_code=HTTPStatus.NOT_FOUND):
  33         self.http_code = http_code
  34         Exception.__init__(self, "database exception " + str(message))
  35
  36
  37 class DbBase(object):
  38
  39     def __init__(self, logger_name='db', lock=False):
  40         """
  41         Constructor of dbBase
  42         :param logger_name: logging name
  43         :param lock: Used to protect simultaneous access to the same instance class by several threads:
  44             False, None: Do not protect, this object will only be accessed by one thread
  45             True: This object needs to be protected by several threads accessing.
  46             Lock object. Use thi Lock for the threads access protection
  47         """
  48         self.logger = logging.getLogger(logger_name)
  49         self.secret_key = None  # 32 bytes length array used for encrypt/decrypt
  50         if not lock:
  51             self.lock = FakeLock()
  52         elif lock is True:
  53             self.lock = Lock()
  54         elif isinstance(lock, Lock):
  55             self.lock = lock
  56         else:
  57             raise ValueError("lock parameter must be a Lock classclass or boolean")
  58
  59     def db_connect(self, config, target_version=None):
  60         """
  61         Connect to database
  62         :param config: Configuration of database. Contains among others:
  63             host:   database hosst (mandatory)
  64             port:   database port (mandatory)
  65             name:   database name (mandatory)
  66             user:   database username
  67             password:   database password
  68             commonkey: common OSM key used for sensible information encryption
  69             materpassword: same as commonkey, for backward compatibility. Deprecated, to be removed in the future
  70         :param target_version: if provided it checks if database contains required version, raising exception otherwise.
  71         :return: None or raises DbException on error
  72         """
  73         raise DbException("Method 'db_connect' not implemented")
  74
  75     def db_disconnect(self):
  76         """
  77         Disconnect from database
  78         :return: None
  79         """
  80         pass
  81
  82     def get_list(self, table, q_filter=None):
  83         """
  84         Obtain a list of entries matching q_filter
  85         :param table: collection or table
  86         :param q_filter: Filter
  87         :return: a list (can be empty) with the found entries. Raises DbException on error
  88         """
  89         raise DbException("Method 'get_list' not implemented")
  90
  91     def get_one(self, table, q_filter=None, fail_on_empty=True, fail_on_more=True):
  92         """
  93         Obtain one entry matching q_filter
  94         :param table: collection or table
  95         :param q_filter: Filter
  96         :param fail_on_empty: If nothing matches filter it returns None unless this flag is set tu True, in which case
  97         it raises a DbException
  98         :param fail_on_more: If more than one matches filter it returns one of then unless this flag is set tu True, so
  99         that it raises a DbException
 100         :return: The requested element, or None
 101         """
 102         raise DbException("Method 'get_one' not implemented")
 103
 104     def del_list(self, table, q_filter=None):
 105         """
 106         Deletes all entries that match q_filter
 107         :param table: collection or table
 108         :param q_filter: Filter
 109         :return: Dict with the number of entries deleted
 110         """
 111         raise DbException("Method 'del_list' not implemented")
 112
 113     def del_one(self, table, q_filter=None, fail_on_empty=True):
 114         """
 115         Deletes one entry that matches q_filter
 116         :param table: collection or table
 117         :param q_filter: Filter
 118         :param fail_on_empty: If nothing matches filter it returns '0' deleted unless this flag is set tu True, in
 119         which case it raises a DbException
 120         :return: Dict with the number of entries deleted
 121         """
 122         raise DbException("Method 'del_one' not implemented")
 123
 124     def create(self, table, indata):
 125         """
 126         Add a new entry at database
 127         :param table: collection or table
 128         :param indata: content to be added
 129         :return: database id of the inserted element. Raises a DbException on error
 130         """
 131         raise DbException("Method 'create' not implemented")
 132
 133     def set_one(self, table, q_filter, update_dict, fail_on_empty=True):
 134         """
 135         Modifies an entry at database
 136         :param table: collection or table
 137         :param q_filter: Filter
 138         :param update_dict: Plain dictionary with the content to be updated. It is a dot separated keys and a value
 139         :param fail_on_empty: If nothing matches filter it returns None unless this flag is set tu True, in which case
 140         it raises a DbException
 141         :return: Dict with the number of entries modified. None if no matching is found.
 142         """
 143         raise DbException("Method 'set_one' not implemented")
 144
 145     def set_list(self, table, q_filter, update_dict):
 146         """
 147         Modifies al matching entries at database
 148         :param table: collection or table
 149         :param q_filter: Filter
 150         :param update_dict: Plain dictionary with the content to be updated. It is a dot separated keys and a value
 151         :return: Dict with the number of entries modified
 152         """
 153         raise DbException("Method 'set_list' not implemented")
 154
 155     def replace(self, table, _id, indata, fail_on_empty=True):
 156         """
 157         Replace the content of an entry
 158         :param table: collection or table
 159         :param _id: internal database id
 160         :param indata: content to replace
 161         :param fail_on_empty: If nothing matches filter it returns None unless this flag is set tu True, in which case
 162         it raises a DbException
 163         :return: Dict with the number of entries replaced
 164         """
 165         raise DbException("Method 'replace' not implemented")
 166
 167     def _join_secret_key(self, update_key):
 168         """
 169         Returns a xor byte combination of the internal secret_key and the provided update_key.
 170         It does not modify the internal secret_key. Used for adding salt, join keys, etc.
 171         :param update_key: Can be a string, byte or None. Recommended a long one (e.g. 32 byte length)
 172         :return: joined key in bytes with a 32 bytes length. Can be None if both internal secret_key and update_key
 173                  are None
 174         """
 175         if not update_key:
 176             return self.secret_key
 177         elif isinstance(update_key, str):
 178             update_key_bytes = update_key.encode()
 179         else:
 180             update_key_bytes = update_key
 181
 182         new_secret_key = bytearray(self.secret_key) if self.secret_key else bytearray(32)
 183         for i, b in enumerate(update_key_bytes):
 184             new_secret_key[i % 32] ^= b
 185         return bytes(new_secret_key)
 186
 187     def set_secret_key(self, new_secret_key, replace=False):
 188         """
 189         Updates internal secret_key used for encryption, with a byte xor
 190         :param new_secret_key: string or byte array. It is recommended a 32 byte length
 191         :param replace: if True, old value of internal secret_key is ignored and replaced. If false, a byte xor is used
 192         :return: None
 193         """
 194         if replace:
 195             self.secret_key = None
 196         self.secret_key = self._join_secret_key(new_secret_key)
 197
 198     def encrypt(self, value, schema_version=None, salt=None):
 199         """
 200         Encrypt a value
 201         :param value: value to be encrypted. It is string/unicode
 202         :param schema_version: used for version control. If None or '1.0' no encryption is done.
 203                If '1.1' symmetric AES encryption is done
 204         :param salt: optional salt to be used. Must be str
 205         :return: Encrypted content of value
 206         """
 207         if not self.secret_key or not schema_version or schema_version == '1.0':
 208             return value
 209         else:
 210             secret_key = self._join_secret_key(salt)
 211             cipher = AES.new(secret_key)
 212             padded_private_msg = value + ('\0' * ((16-len(value)) % 16))
 213             encrypted_msg = cipher.encrypt(padded_private_msg)
 214             encoded_encrypted_msg = b64encode(encrypted_msg)
 215             return encoded_encrypted_msg.decode("ascii")
 216
 217     def decrypt(self, value, schema_version=None, salt=None):
 218         """
 219         Decrypt an encrypted value
 220         :param value: value to be decrypted. It is a base64 string
 221         :param schema_version: used for known encryption method used. If None or '1.0' no encryption has been done.
 222                If '1.1' symmetric AES encryption has been done
 223         :param salt: optional salt to be used
 224         :return: Plain content of value
 225         """
 226         if not self.secret_key or not schema_version or schema_version == '1.0':
 227             return value
 228         else:
 229             secret_key = self._join_secret_key(salt)
 230             encrypted_msg = b64decode(value)
 231             cipher = AES.new(secret_key)
 232             decrypted_msg = cipher.decrypt(encrypted_msg)
 233             unpadded_private_msg = decrypted_msg.decode().rstrip('\0')
 234             return unpadded_private_msg
 235
 236
 237 def deep_update_rfc7396(dict_to_change, dict_reference, key_list=None):
 238     """
 239     Modifies one dictionary with the information of the other following https://tools.ietf.org/html/rfc7396
 240     Basically is a recursive python 'dict_to_change.update(dict_reference)', but a value of None is used to delete.
 241     It implements an extra feature that allows modifying an array. RFC7396 only allows replacing the entire array.
 242     For that, dict_reference should contains a dict with keys starting by "$" with the following meaning:
 243         $[index]    <index> is an integer for targeting a concrete index from dict_to_change array. If the value is None
 244                     the element of the array is deleted, otherwise it is edited.
 245         $+[index]   The value is inserted at this <index>. A value of None has not sense and an exception is raised.
 246         $+          The value is appended at the end. A value of None has not sense and an exception is raised.
 247         $val        It looks for all the items in the array dict_to_change equal to <val>. <val> is evaluated as yaml,
 248                     that is, numbers are taken as type int, true/false as boolean, etc. Use quotes to force string.
 249                     Nothing happens if no match is found. If the value is None the matched elements are deleted.
 250         $key: val   In case a dictionary is passed in yaml format, if looks for all items in the array dict_to_change
 251                     that are dictionaries and contains this <key> equal to <val>. Several keys can be used by yaml
 252                     format '{key: val, key: val, ...}'; and all of them mast match. Nothing happens if no match is
 253                     found. If value is None the matched items are deleted, otherwise they are edited.
 254         $+val       If no match if found (see '$val'), the value is appended to the array. If any match is found nothing
 255                     is changed. A value of None has not sense.
 256         $+key: val  If no match if found (see '$key: val'), the value is appended to the array. If any match is found
 257                     nothing is changed. A value of None has not sense.
 258     If there are several editions, insertions and deletions; editions and deletions are done first in reverse index
 259         order; then insertions also in reverse index order; and finally appends in any order. So indexes used at
 260         insertions must take into account the deleted items.
 261     :param dict_to_change:  Target dictionary to be changed.
 262     :param dict_reference: Dictionary that contains changes to be applied.
 263     :param key_list: This is used internally for recursive calls. Do not fill this parameter.
 264     :return: none or raises and exception only at array modification when there is a bad format or conflict.
 265     """
 266     def _deep_update_array(array_to_change, _dict_reference, _key_list):
 267         to_append = {}
 268         to_insert_at_index = {}
 269         values_to_edit_delete = {}
 270         indexes_to_edit_delete = []
 271         array_edition = None
 272         _key_list.append("")
 273         for k in _dict_reference:
 274             _key_list[-1] = str(k)
 275             if not isinstance(k, str) or not k.startswith("$"):
 276                 if array_edition is True:
 277                     raise DbException("Found array edition (keys starting with '$') and pure dictionary edition in the"
 278                                       " same dict at '{}'".format(":".join(_key_list[:-1])))
 279                 array_edition = False
 280                 continue
 281             else:
 282                 if array_edition is False:
 283                     raise DbException("Found array edition (keys starting with '$') and pure dictionary edition in the"
 284                                       " same dict at '{}'".format(":".join(_key_list[:-1])))
 285                 array_edition = True
 286             insert = False
 287             indexes = []  # indexes to edit or insert
 288             kitem = k[1:]
 289             if kitem.startswith('+'):
 290                 insert = True
 291                 kitem = kitem[1:]
 292                 if _dict_reference[k] is None:
 293                     raise DbException("A value of None has not sense for insertions at '{}'".format(
 294                         ":".join(_key_list)))
 295
 296             if kitem.startswith('[') and kitem.endswith(']'):
 297                 try:
 298                     index = int(kitem[1:-1])
 299                     if index < 0:
 300                         index += len(array_to_change)
 301                     if index < 0:
 302                         index = 0  # skip outside index edition
 303                     indexes.append(index)
 304                 except Exception:
 305                     raise DbException("Wrong format at '{}'. Expecting integer index inside quotes".format(
 306                         ":".join(_key_list)))
 307             elif kitem:
 308                 # match_found_skip = False
 309                 try:
 310                     filter_in = yaml.safe_load(kitem)
 311                 except Exception:
 312                     raise DbException("Wrong format at '{}'. Expecting '$<yaml-format>'".format(":".join(_key_list)))
 313                 if isinstance(filter_in, dict):
 314                     for index, item in enumerate(array_to_change):
 315                         for filter_k, filter_v in filter_in.items():
 316                             if not isinstance(item, dict) or filter_k not in item or item[filter_k] != filter_v:
 317                                 break
 318                         else:  # match found
 319                             if insert:
 320                                 # match_found_skip = True
 321                                 insert = False
 322                                 break
 323                             else:
 324                                 indexes.append(index)
 325                 else:
 326                     index = 0
 327                     try:
 328                         while True:  # if not match a ValueError exception will be raise
 329                             index = array_to_change.index(filter_in, index)
 330                             if insert:
 331                                 # match_found_skip = True
 332                                 insert = False
 333                                 break
 334                             indexes.append(index)
 335                             index += 1
 336                     except ValueError:
 337                         pass
 338
 339                 # if match_found_skip:
 340                 #     continue
 341             elif not insert:
 342                 raise DbException("Wrong format at '{}'. Expecting '$+', '$[<index]' or '$[<filter>]'".format(
 343                     ":".join(_key_list)))
 344             for index in indexes:
 345                 if insert:
 346                     if index in to_insert_at_index and to_insert_at_index[index] != _dict_reference[k]:
 347                         # Several different insertions on the same item of the array
 348                         raise DbException("Conflict at '{}'. Several insertions on same array index {}".format(
 349                             ":".join(_key_list), index))
 350                     to_insert_at_index[index] = _dict_reference[k]
 351                 else:
 352                     if index in indexes_to_edit_delete and values_to_edit_delete[index] != _dict_reference[k]:
 353                         # Several different editions on the same item of the array
 354                         raise DbException("Conflict at '{}'. Several editions on array index {}".format(
 355                             ":".join(_key_list), index))
 356                     indexes_to_edit_delete.append(index)
 357                     values_to_edit_delete[index] = _dict_reference[k]
 358             if not indexes:
 359                 if insert:
 360                     to_append[k] = _dict_reference[k]
 361                 # elif _dict_reference[k] is not None:
 362                 #     raise DbException("Not found any match to edit in the array, or wrong format at '{}'".format(
 363                 #         ":".join(_key_list)))
 364
 365         # edition/deletion is done before insertion
 366         indexes_to_edit_delete.sort(reverse=True)
 367         for index in indexes_to_edit_delete:
 368             _key_list[-1] = str(index)
 369             try:
 370                 if values_to_edit_delete[index] is None:  # None->Anything
 371                     try:
 372                         del (array_to_change[index])
 373                     except IndexError:
 374                         pass  # it is not consider an error if this index does not exist
 375                 elif not isinstance(values_to_edit_delete[index], dict):  # NotDict->Anything
 376                     array_to_change[index] = deepcopy(values_to_edit_delete[index])
 377                 elif isinstance(array_to_change[index], dict):  # Dict->Dict
 378                     deep_update_rfc7396(array_to_change[index], values_to_edit_delete[index], _key_list)
 379                 else:  # Dict->NotDict
 380                     if isinstance(array_to_change[index], list):  # Dict->List. Check extra array edition
 381                         if _deep_update_array(array_to_change[index], values_to_edit_delete[index], _key_list):
 382                             continue
 383                     array_to_change[index] = deepcopy(values_to_edit_delete[index])
 384                     # calling deep_update_rfc7396 to delete the None values
 385                     deep_update_rfc7396(array_to_change[index], values_to_edit_delete[index], _key_list)
 386             except IndexError:
 387                 raise DbException("Array edition index out of range at '{}'".format(":".join(_key_list)))
 388
 389         # insertion with indexes
 390         to_insert_indexes = list(to_insert_at_index.keys())
 391         to_insert_indexes.sort(reverse=True)
 392         for index in to_insert_indexes:
 393             array_to_change.insert(index, to_insert_at_index[index])
 394
 395         # append
 396         for k, insert_value in to_append.items():
 397             _key_list[-1] = str(k)
 398             insert_value_copy = deepcopy(insert_value)
 399             if isinstance(insert_value_copy, dict):
 400                 # calling deep_update_rfc7396 to delete the None values
 401                 deep_update_rfc7396(insert_value_copy, insert_value, _key_list)
 402             array_to_change.append(insert_value_copy)
 403
 404         _key_list.pop()
 405         if array_edition:
 406             return True
 407         return False
 408
 409     if key_list is None:
 410         key_list = []
 411     key_list.append("")
 412     for k in dict_reference:
 413         key_list[-1] = str(k)
 414         if dict_reference[k] is None:   # None->Anything
 415             if k in dict_to_change:
 416                 del dict_to_change[k]
 417         elif not isinstance(dict_reference[k], dict):  # NotDict->Anything
 418             dict_to_change[k] = deepcopy(dict_reference[k])
 419         elif k not in dict_to_change:  # Dict->Empty
 420             dict_to_change[k] = deepcopy(dict_reference[k])
 421             # calling deep_update_rfc7396 to delete the None values
 422             deep_update_rfc7396(dict_to_change[k], dict_reference[k], key_list)
 423         elif isinstance(dict_to_change[k], dict):  # Dict->Dict
 424             deep_update_rfc7396(dict_to_change[k], dict_reference[k], key_list)
 425         else:       # Dict->NotDict
 426             if isinstance(dict_to_change[k], list):  # Dict->List. Check extra array edition
 427                 if _deep_update_array(dict_to_change[k], dict_reference[k], key_list):
 428                     continue
 429             dict_to_change[k] = deepcopy(dict_reference[k])
 430             # calling deep_update_rfc7396 to delete the None values
 431             deep_update_rfc7396(dict_to_change[k], dict_reference[k], key_list)
 432     key_list.pop()
 433
 434
 435 def deep_update(dict_to_change, dict_reference):
 436     """ Maintained for backward compatibility. Use deep_update_rfc7396 instead"""
 437     return deep_update_rfc7396(dict_to_change, dict_reference)