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 import re
  21 from http import HTTPStatus
  22 from copy import deepcopy
  23 from Crypto.Cipher import AES
  24 from base64 import b64decode, b64encode
  25 from osm_common.common_utils import FakeLock
  26 from threading import Lock
  27
  28 __author__ = "Alfonso Tierno <alfonso.tiernosepulveda@telefonica.com>"
  29
  30
  31 class DbException(Exception):
  32
  33     def __init__(self, message, http_code=HTTPStatus.NOT_FOUND):
  34         self.http_code = http_code
  35         Exception.__init__(self, "database exception " + str(message))
  36
  37
  38 class DbBase(object):
  39
  40     def __init__(self, logger_name='db', lock=False):
  41         """
  42         Constructor of dbBase
  43         :param logger_name: logging name
  44         :param lock: Used to protect simultaneous access to the same instance class by several threads:
  45             False, None: Do not protect, this object will only be accessed by one thread
  46             True: This object needs to be protected by several threads accessing.
  47             Lock object. Use thi Lock for the threads access protection
  48         """
  49         self.logger = logging.getLogger(logger_name)
  50         self.secret_key = None  # 32 bytes length array used for encrypt/decrypt
  51         if not lock:
  52             self.lock = FakeLock()
  53         elif lock is True:
  54             self.lock = Lock()
  55         elif isinstance(lock, Lock):
  56             self.lock = lock
  57         else:
  58             raise ValueError("lock parameter must be a Lock classclass or boolean")
  59
  60     def db_connect(self, config, target_version=None):
  61         """
  62         Connect to database
  63         :param config: Configuration of database. Contains among others:
  64             host:   database hosst (mandatory)
  65             port:   database port (mandatory)
  66             name:   database name (mandatory)
  67             user:   database username
  68             password:   database password
  69             commonkey: common OSM key used for sensible information encryption
  70             materpassword: same as commonkey, for backward compatibility. Deprecated, to be removed in the future
  71         :param target_version: if provided it checks if database contains required version, raising exception otherwise.
  72         :return: None or raises DbException on error
  73         """
  74         raise DbException("Method 'db_connect' not implemented")
  75
  76     def db_disconnect(self):
  77         """
  78         Disconnect from database
  79         :return: None
  80         """
  81         pass
  82
  83     def get_list(self, table, q_filter=None):
  84         """
  85         Obtain a list of entries matching q_filter
  86         :param table: collection or table
  87         :param q_filter: Filter
  88         :return: a list (can be empty) with the found entries. Raises DbException on error
  89         """
  90         raise DbException("Method 'get_list' not implemented")
  91
  92     def count(self, table, q_filter=None):
  93         """
  94         Count the number of entries matching q_filter
  95         :param table: collection or table
  96         :param q_filter: Filter
  97         :return: number of entries found (can be zero)
  98         :raise: DbException on error
  99         """
 100         raise DbException("Method 'count' not implemented")
 101
 102     def get_one(self, table, q_filter=None, fail_on_empty=True, fail_on_more=True):
 103         """
 104         Obtain one entry matching q_filter
 105         :param table: collection or table
 106         :param q_filter: Filter
 107         :param fail_on_empty: If nothing matches filter it returns None unless this flag is set tu True, in which case
 108         it raises a DbException
 109         :param fail_on_more: If more than one matches filter it returns one of then unless this flag is set tu True, so
 110         that it raises a DbException
 111         :return: The requested element, or None
 112         """
 113         raise DbException("Method 'get_one' not implemented")
 114
 115     def del_list(self, table, q_filter=None):
 116         """
 117         Deletes all entries that match q_filter
 118         :param table: collection or table
 119         :param q_filter: Filter
 120         :return: Dict with the number of entries deleted
 121         """
 122         raise DbException("Method 'del_list' not implemented")
 123
 124     def del_one(self, table, q_filter=None, fail_on_empty=True):
 125         """
 126         Deletes one entry that matches q_filter
 127         :param table: collection or table
 128         :param q_filter: Filter
 129         :param fail_on_empty: If nothing matches filter it returns '0' deleted unless this flag is set tu True, in
 130         which case it raises a DbException
 131         :return: Dict with the number of entries deleted
 132         """
 133         raise DbException("Method 'del_one' not implemented")
 134
 135     def create(self, table, indata):
 136         """
 137         Add a new entry at database
 138         :param table: collection or table
 139         :param indata: content to be added
 140         :return: database id of the inserted element. Raises a DbException on error
 141         """
 142         raise DbException("Method 'create' not implemented")
 143
 144     def set_one(self, table, q_filter, update_dict, fail_on_empty=True, unset=None, pull=None, push=None):
 145         """
 146         Modifies an entry at database
 147         :param table: collection or table
 148         :param q_filter: Filter
 149         :param update_dict: Plain dictionary with the content to be updated. It is a dot separated keys and a value
 150         :param fail_on_empty: If nothing matches filter it returns None unless this flag is set tu True, in which case
 151         it raises a DbException
 152         :param unset: Plain dictionary with the content to be removed if exist. It is a dot separated keys, value is
 153                       ignored. If not exist, it is ignored
 154         :param pull: Plain dictionary with the content to be removed from an array. It is a dot separated keys and value
 155                      if exist in the array is removed. If not exist, it is ignored
 156         :param push: Plain dictionary with the content to be appended to an array. It is a dot separated keys and value
 157                      is appended to the end of the array
 158         :return: Dict with the number of entries modified. None if no matching is found.
 159         """
 160         raise DbException("Method 'set_one' not implemented")
 161
 162     def set_list(self, table, q_filter, update_dict):
 163         """
 164         Modifies al matching entries at database
 165         :param table: collection or table
 166         :param q_filter: Filter
 167         :param update_dict: Plain dictionary with the content to be updated. It is a dot separated keys and a value
 168         :return: Dict with the number of entries modified
 169         """
 170         raise DbException("Method 'set_list' not implemented")
 171
 172     def replace(self, table, _id, indata, fail_on_empty=True):
 173         """
 174         Replace the content of an entry
 175         :param table: collection or table
 176         :param _id: internal database id
 177         :param indata: content to replace
 178         :param fail_on_empty: If nothing matches filter it returns None unless this flag is set tu True, in which case
 179         it raises a DbException
 180         :return: Dict with the number of entries replaced
 181         """
 182         raise DbException("Method 'replace' not implemented")
 183
 184     def _join_secret_key(self, update_key):
 185         """
 186         Returns a xor byte combination of the internal secret_key and the provided update_key.
 187         It does not modify the internal secret_key. Used for adding salt, join keys, etc.
 188         :param update_key: Can be a string, byte or None. Recommended a long one (e.g. 32 byte length)
 189         :return: joined key in bytes with a 32 bytes length. Can be None if both internal secret_key and update_key
 190                  are None
 191         """
 192         if not update_key:
 193             return self.secret_key
 194         elif isinstance(update_key, str):
 195             update_key_bytes = update_key.encode()
 196         else:
 197             update_key_bytes = update_key
 198
 199         new_secret_key = bytearray(self.secret_key) if self.secret_key else bytearray(32)
 200         for i, b in enumerate(update_key_bytes):
 201             new_secret_key[i % 32] ^= b
 202         return bytes(new_secret_key)
 203
 204     def set_secret_key(self, new_secret_key, replace=False):
 205         """
 206         Updates internal secret_key used for encryption, with a byte xor
 207         :param new_secret_key: string or byte array. It is recommended a 32 byte length
 208         :param replace: if True, old value of internal secret_key is ignored and replaced. If false, a byte xor is used
 209         :return: None
 210         """
 211         if replace:
 212             self.secret_key = None
 213         self.secret_key = self._join_secret_key(new_secret_key)
 214
 215     def encrypt(self, value, schema_version=None, salt=None):
 216         """
 217         Encrypt a value
 218         :param value: value to be encrypted. It is string/unicode
 219         :param schema_version: used for version control. If None or '1.0' no encryption is done.
 220                If '1.1' symmetric AES encryption is done
 221         :param salt: optional salt to be used. Must be str
 222         :return: Encrypted content of value
 223         """
 224         if not self.secret_key or not schema_version or schema_version == '1.0':
 225             return value
 226         else:
 227             secret_key = self._join_secret_key(salt)
 228             cipher = AES.new(secret_key)
 229             padded_private_msg = value + ('\0' * ((16-len(value)) % 16))
 230             encrypted_msg = cipher.encrypt(padded_private_msg)
 231             encoded_encrypted_msg = b64encode(encrypted_msg)
 232             return encoded_encrypted_msg.decode("ascii")
 233
 234     def decrypt(self, value, schema_version=None, salt=None):
 235         """
 236         Decrypt an encrypted value
 237         :param value: value to be decrypted. It is a base64 string
 238         :param schema_version: used for known encryption method used. If None or '1.0' no encryption has been done.
 239                If '1.1' symmetric AES encryption has been done
 240         :param salt: optional salt to be used
 241         :return: Plain content of value
 242         """
 243         if not self.secret_key or not schema_version or schema_version == '1.0':
 244             return value
 245         else:
 246             secret_key = self._join_secret_key(salt)
 247             encrypted_msg = b64decode(value)
 248             cipher = AES.new(secret_key)
 249             decrypted_msg = cipher.decrypt(encrypted_msg)
 250             try:
 251                 unpadded_private_msg = decrypted_msg.decode().rstrip('\0')
 252             except UnicodeDecodeError:
 253                 raise DbException("Cannot decrypt information. Are you using same COMMONKEY in all OSM components?",
 254                                   http_code=HTTPStatus.INTERNAL_SERVER_ERROR)
 255             return unpadded_private_msg
 256
 257     def encrypt_decrypt_fields(self, item, action, fields=None, flags=re.I, schema_version=None, salt=None):
 258         if not fields:
 259             return
 260         actions = ['encrypt', 'decrypt']
 261         if action.lower() not in actions:
 262             raise DbException("Unknown action ({}): Must be one of {}".format(action, actions),
 263                               http_code=HTTPStatus.INTERNAL_SERVER_ERROR)
 264         method = self.encrypt if action.lower() == 'encrypt' else self.decrypt
 265
 266         def process(item):
 267             if isinstance(item, list):
 268                 for elem in item:
 269                     process(elem)
 270             elif isinstance(item, dict):
 271                 for key, val in item.items():
 272                     if any(re.search(f, key, flags) for f in fields) and isinstance(val, str):
 273                         item[key] = method(val, schema_version, salt)
 274                     else:
 275                         process(val)
 276
 277         process(item)
 278
 279
 280 def deep_update_rfc7396(dict_to_change, dict_reference, key_list=None):
 281     """
 282     Modifies one dictionary with the information of the other following https://tools.ietf.org/html/rfc7396
 283     Basically is a recursive python 'dict_to_change.update(dict_reference)', but a value of None is used to delete.
 284     It implements an extra feature that allows modifying an array. RFC7396 only allows replacing the entire array.
 285     For that, dict_reference should contains a dict with keys starting by "$" with the following meaning:
 286         $[index]    <index> is an integer for targeting a concrete index from dict_to_change array. If the value is None
 287                     the element of the array is deleted, otherwise it is edited.
 288         $+[index]   The value is inserted at this <index>. A value of None has not sense and an exception is raised.
 289         $+          The value is appended at the end. A value of None has not sense and an exception is raised.
 290         $val        It looks for all the items in the array dict_to_change equal to <val>. <val> is evaluated as yaml,
 291                     that is, numbers are taken as type int, true/false as boolean, etc. Use quotes to force string.
 292                     Nothing happens if no match is found. If the value is None the matched elements are deleted.
 293         $key: val   In case a dictionary is passed in yaml format, if looks for all items in the array dict_to_change
 294                     that are dictionaries and contains this <key> equal to <val>. Several keys can be used by yaml
 295                     format '{key: val, key: val, ...}'; and all of them must match. Nothing happens if no match is
 296                     found. If value is None the matched items are deleted, otherwise they are edited.
 297         $+val       If no match if found (see '$val'), the value is appended to the array. If any match is found nothing
 298                     is changed. A value of None has not sense.
 299         $+key: val  If no match if found (see '$key: val'), the value is appended to the array. If any match is found
 300                     nothing is changed. A value of None has not sense.
 301     If there are several editions, insertions and deletions; editions and deletions are done first in reverse index
 302         order; then insertions also in reverse index order; and finally appends in any order. So indexes used at
 303         insertions must take into account the deleted items.
 304     :param dict_to_change:  Target dictionary to be changed.
 305     :param dict_reference: Dictionary that contains changes to be applied.
 306     :param key_list: This is used internally for recursive calls. Do not fill this parameter.
 307     :return: none or raises and exception only at array modification when there is a bad format or conflict.
 308     """
 309     def _deep_update_array(array_to_change, _dict_reference, _key_list):
 310         to_append = {}
 311         to_insert_at_index = {}
 312         values_to_edit_delete = {}
 313         indexes_to_edit_delete = []
 314         array_edition = None
 315         _key_list.append("")
 316         for k in _dict_reference:
 317             _key_list[-1] = str(k)
 318             if not isinstance(k, str) or not k.startswith("$"):
 319                 if array_edition is True:
 320                     raise DbException("Found array edition (keys starting with '$') and pure dictionary edition in the"
 321                                       " same dict at '{}'".format(":".join(_key_list[:-1])))
 322                 array_edition = False
 323                 continue
 324             else:
 325                 if array_edition is False:
 326                     raise DbException("Found array edition (keys starting with '$') and pure dictionary edition in the"
 327                                       " same dict at '{}'".format(":".join(_key_list[:-1])))
 328                 array_edition = True
 329             insert = False
 330             indexes = []  # indexes to edit or insert
 331             kitem = k[1:]
 332             if kitem.startswith('+'):
 333                 insert = True
 334                 kitem = kitem[1:]
 335                 if _dict_reference[k] is None:
 336                     raise DbException("A value of None has not sense for insertions at '{}'".format(
 337                         ":".join(_key_list)))
 338
 339             if kitem.startswith('[') and kitem.endswith(']'):
 340                 try:
 341                     index = int(kitem[1:-1])
 342                     if index < 0:
 343                         index += len(array_to_change)
 344                     if index < 0:
 345                         index = 0  # skip outside index edition
 346                     indexes.append(index)
 347                 except Exception:
 348                     raise DbException("Wrong format at '{}'. Expecting integer index inside quotes".format(
 349                         ":".join(_key_list)))
 350             elif kitem:
 351                 # match_found_skip = False
 352                 try:
 353                     filter_in = yaml.safe_load(kitem)
 354                 except Exception:
 355                     raise DbException("Wrong format at '{}'. Expecting '$<yaml-format>'".format(":".join(_key_list)))
 356                 if isinstance(filter_in, dict):
 357                     for index, item in enumerate(array_to_change):
 358                         for filter_k, filter_v in filter_in.items():
 359                             if not isinstance(item, dict) or filter_k not in item or item[filter_k] != filter_v:
 360                                 break
 361                         else:  # match found
 362                             if insert:
 363                                 # match_found_skip = True
 364                                 insert = False
 365                                 break
 366                             else:
 367                                 indexes.append(index)
 368                 else:
 369                     index = 0
 370                     try:
 371                         while True:  # if not match a ValueError exception will be raise
 372                             index = array_to_change.index(filter_in, index)
 373                             if insert:
 374                                 # match_found_skip = True
 375                                 insert = False
 376                                 break
 377                             indexes.append(index)
 378                             index += 1
 379                     except ValueError:
 380                         pass
 381
 382                 # if match_found_skip:
 383                 #     continue
 384             elif not insert:
 385                 raise DbException("Wrong format at '{}'. Expecting '$+', '$[<index]' or '$[<filter>]'".format(
 386                     ":".join(_key_list)))
 387             for index in indexes:
 388                 if insert:
 389                     if index in to_insert_at_index and to_insert_at_index[index] != _dict_reference[k]:
 390                         # Several different insertions on the same item of the array
 391                         raise DbException("Conflict at '{}'. Several insertions on same array index {}".format(
 392                             ":".join(_key_list), index))
 393                     to_insert_at_index[index] = _dict_reference[k]
 394                 else:
 395                     if index in indexes_to_edit_delete and values_to_edit_delete[index] != _dict_reference[k]:
 396                         # Several different editions on the same item of the array
 397                         raise DbException("Conflict at '{}'. Several editions on array index {}".format(
 398                             ":".join(_key_list), index))
 399                     indexes_to_edit_delete.append(index)
 400                     values_to_edit_delete[index] = _dict_reference[k]
 401             if not indexes:
 402                 if insert:
 403                     to_append[k] = _dict_reference[k]
 404                 # elif _dict_reference[k] is not None:
 405                 #     raise DbException("Not found any match to edit in the array, or wrong format at '{}'".format(
 406                 #         ":".join(_key_list)))
 407
 408         # edition/deletion is done before insertion
 409         indexes_to_edit_delete.sort(reverse=True)
 410         for index in indexes_to_edit_delete:
 411             _key_list[-1] = str(index)
 412             try:
 413                 if values_to_edit_delete[index] is None:  # None->Anything
 414                     try:
 415                         del (array_to_change[index])
 416                     except IndexError:
 417                         pass  # it is not consider an error if this index does not exist
 418                 elif not isinstance(values_to_edit_delete[index], dict):  # NotDict->Anything
 419                     array_to_change[index] = deepcopy(values_to_edit_delete[index])
 420                 elif isinstance(array_to_change[index], dict):  # Dict->Dict
 421                     deep_update_rfc7396(array_to_change[index], values_to_edit_delete[index], _key_list)
 422                 else:  # Dict->NotDict
 423                     if isinstance(array_to_change[index], list):  # Dict->List. Check extra array edition
 424                         if _deep_update_array(array_to_change[index], values_to_edit_delete[index], _key_list):
 425                             continue
 426                     array_to_change[index] = deepcopy(values_to_edit_delete[index])
 427                     # calling deep_update_rfc7396 to delete the None values
 428                     deep_update_rfc7396(array_to_change[index], values_to_edit_delete[index], _key_list)
 429             except IndexError:
 430                 raise DbException("Array edition index out of range at '{}'".format(":".join(_key_list)))
 431
 432         # insertion with indexes
 433         to_insert_indexes = list(to_insert_at_index.keys())
 434         to_insert_indexes.sort(reverse=True)
 435         for index in to_insert_indexes:
 436             array_to_change.insert(index, to_insert_at_index[index])
 437
 438         # append
 439         for k, insert_value in to_append.items():
 440             _key_list[-1] = str(k)
 441             insert_value_copy = deepcopy(insert_value)
 442             if isinstance(insert_value_copy, dict):
 443                 # calling deep_update_rfc7396 to delete the None values
 444                 deep_update_rfc7396(insert_value_copy, insert_value, _key_list)
 445             array_to_change.append(insert_value_copy)
 446
 447         _key_list.pop()
 448         if array_edition:
 449             return True
 450         return False
 451
 452     if key_list is None:
 453         key_list = []
 454     key_list.append("")
 455     for k in dict_reference:
 456         key_list[-1] = str(k)
 457         if dict_reference[k] is None:   # None->Anything
 458             if k in dict_to_change:
 459                 del dict_to_change[k]
 460         elif not isinstance(dict_reference[k], dict):  # NotDict->Anything
 461             dict_to_change[k] = deepcopy(dict_reference[k])
 462         elif k not in dict_to_change:  # Dict->Empty
 463             dict_to_change[k] = deepcopy(dict_reference[k])
 464             # calling deep_update_rfc7396 to delete the None values
 465             deep_update_rfc7396(dict_to_change[k], dict_reference[k], key_list)
 466         elif isinstance(dict_to_change[k], dict):  # Dict->Dict
 467             deep_update_rfc7396(dict_to_change[k], dict_reference[k], key_list)
 468         else:       # Dict->NotDict
 469             if isinstance(dict_to_change[k], list):  # Dict->List. Check extra array edition
 470                 if _deep_update_array(dict_to_change[k], dict_reference[k], key_list):
 471                     continue
 472             dict_to_change[k] = deepcopy(dict_reference[k])
 473             # calling deep_update_rfc7396 to delete the None values
 474             deep_update_rfc7396(dict_to_change[k], dict_reference[k], key_list)
 475     key_list.pop()
 476
 477
 478 def deep_update(dict_to_change, dict_reference):
 479     """ Maintained for backward compatibility. Use deep_update_rfc7396 instead"""
 480     return deep_update_rfc7396(dict_to_change, dict_reference)