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 host (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 create_list(self, table, indata_list):
 145         """
 146         Add several entries at once
 147         :param table: collection or table
 148         :param indata_list: list of elements to insert. Each element must be a dictionary.
 149             An '_id' key based on random uuid is added at each element if missing
 150         :return: list of inserted '_id's. Exception on error
 151         """
 152         raise DbException("Method 'create_list' not implemented")
 153
 154     def set_one(self, table, q_filter, update_dict, fail_on_empty=True, unset=None, pull=None, push=None,
 155                 push_list=None):
 156         """
 157         Modifies an entry at database
 158         :param table: collection or table
 159         :param q_filter: Filter
 160         :param update_dict: Plain dictionary with the content to be updated. It is a dot separated keys and a value
 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         :param unset: Plain dictionary with the content to be removed if exist. It is a dot separated keys, value is
 164                       ignored. If not exist, it is ignored
 165         :param pull: Plain dictionary with the content to be removed from an array. It is a dot separated keys and value
 166                      if exist in the array is removed. If not exist, it is ignored
 167         :param push: Plain dictionary with the content to be appended to an array. It is a dot separated keys and value
 168                      is appended to the end of the array
 169         :param push_list: Same as push but values are arrays where each item is and appended instead of appending the
 170                           whole array
 171         :return: Dict with the number of entries modified. None if no matching is found.
 172         """
 173         raise DbException("Method 'set_one' not implemented")
 174
 175     def set_list(self, table, q_filter, update_dict, unset=None, pull=None, push=None, push_list=None):
 176         """
 177         Modifies al matching entries at database
 178         :param table: collection or table
 179         :param q_filter: Filter
 180         :param update_dict: Plain dictionary with the content to be updated. It is a dot separated keys and a value
 181         :param unset: Plain dictionary with the content to be removed if exist. It is a dot separated keys, value is
 182                       ignored. If not exist, it is ignored
 183         :param pull: Plain dictionary with the content to be removed from an array. It is a dot separated keys and value
 184                      if exist in the array is removed. If not exist, it is ignored
 185         :param push: Plain dictionary with the content to be appended to an array. It is a dot separated keys and value
 186                      is appended to the end of the array
 187         :param push_list: Same as push but values are arrays where each item is and appended instead of appending the
 188                           whole array
 189         :return: Dict with the number of entries modified
 190         """
 191         raise DbException("Method 'set_list' not implemented")
 192
 193     def replace(self, table, _id, indata, fail_on_empty=True):
 194         """
 195         Replace the content of an entry
 196         :param table: collection or table
 197         :param _id: internal database id
 198         :param indata: content to replace
 199         :param fail_on_empty: If nothing matches filter it returns None unless this flag is set tu True, in which case
 200         it raises a DbException
 201         :return: Dict with the number of entries replaced
 202         """
 203         raise DbException("Method 'replace' not implemented")
 204
 205     def _join_secret_key(self, update_key):
 206         """
 207         Returns a xor byte combination of the internal secret_key and the provided update_key.
 208         It does not modify the internal secret_key. Used for adding salt, join keys, etc.
 209         :param update_key: Can be a string, byte or None. Recommended a long one (e.g. 32 byte length)
 210         :return: joined key in bytes with a 32 bytes length. Can be None if both internal secret_key and update_key
 211                  are None
 212         """
 213         if not update_key:
 214             return self.secret_key
 215         elif isinstance(update_key, str):
 216             update_key_bytes = update_key.encode()
 217         else:
 218             update_key_bytes = update_key
 219
 220         new_secret_key = bytearray(self.secret_key) if self.secret_key else bytearray(32)
 221         for i, b in enumerate(update_key_bytes):
 222             new_secret_key[i % 32] ^= b
 223         return bytes(new_secret_key)
 224
 225     def set_secret_key(self, new_secret_key, replace=False):
 226         """
 227         Updates internal secret_key used for encryption, with a byte xor
 228         :param new_secret_key: string or byte array. It is recommended a 32 byte length
 229         :param replace: if True, old value of internal secret_key is ignored and replaced. If false, a byte xor is used
 230         :return: None
 231         """
 232         if replace:
 233             self.secret_key = None
 234         self.secret_key = self._join_secret_key(new_secret_key)
 235
 236     def get_secret_key(self):
 237         """
 238         Get the database secret key in case it is not done when "connect" is called. It can happens when database is
 239         empty after an initial install. It should skip if secret is already obtained.
 240         """
 241         pass
 242
 243     def encrypt(self, value, schema_version=None, salt=None):
 244         """
 245         Encrypt a value
 246         :param value: value to be encrypted. It is string/unicode
 247         :param schema_version: used for version control. If None or '1.0' no encryption is done.
 248                If '1.1' symmetric AES encryption is done
 249         :param salt: optional salt to be used. Must be str
 250         :return: Encrypted content of value
 251         """
 252         self.get_secret_key()
 253         if not self.secret_key or not schema_version or schema_version == '1.0':
 254             return value
 255         else:
 256             secret_key = self._join_secret_key(salt)
 257             cipher = AES.new(secret_key)
 258             padded_private_msg = value + ('\0' * ((16-len(value)) % 16))
 259             encrypted_msg = cipher.encrypt(padded_private_msg)
 260             encoded_encrypted_msg = b64encode(encrypted_msg)
 261             return encoded_encrypted_msg.decode("ascii")
 262
 263     def decrypt(self, value, schema_version=None, salt=None):
 264         """
 265         Decrypt an encrypted value
 266         :param value: value to be decrypted. It is a base64 string
 267         :param schema_version: used for known encryption method used. If None or '1.0' no encryption has been done.
 268                If '1.1' symmetric AES encryption has been done
 269         :param salt: optional salt to be used
 270         :return: Plain content of value
 271         """
 272         self.get_secret_key()
 273         if not self.secret_key or not schema_version or schema_version == '1.0':
 274             return value
 275         else:
 276             secret_key = self._join_secret_key(salt)
 277             encrypted_msg = b64decode(value)
 278             cipher = AES.new(secret_key)
 279             decrypted_msg = cipher.decrypt(encrypted_msg)
 280             try:
 281                 unpadded_private_msg = decrypted_msg.decode().rstrip('\0')
 282             except UnicodeDecodeError:
 283                 raise DbException("Cannot decrypt information. Are you using same COMMONKEY in all OSM components?",
 284                                   http_code=HTTPStatus.INTERNAL_SERVER_ERROR)
 285             return unpadded_private_msg
 286
 287     def encrypt_decrypt_fields(self, item, action, fields=None, flags=None, schema_version=None, salt=None):
 288         if not fields:
 289             return
 290         self.get_secret_key()
 291         actions = ['encrypt', 'decrypt']
 292         if action.lower() not in actions:
 293             raise DbException("Unknown action ({}): Must be one of {}".format(action, actions),
 294                               http_code=HTTPStatus.INTERNAL_SERVER_ERROR)
 295         method = self.encrypt if action.lower() == 'encrypt' else self.decrypt
 296         if flags is None:
 297             flags = re.I
 298
 299         def process(_item):
 300             if isinstance(_item, list):
 301                 for elem in _item:
 302                     process(elem)
 303             elif isinstance(_item, dict):
 304                 for key, val in _item.items():
 305                     if isinstance(val, str):
 306                         if any(re.search(f, key, flags) for f in fields):
 307                             _item[key] = method(val, schema_version, salt)
 308                     else:
 309                         process(val)
 310         process(item)
 311
 312
 313 def deep_update_rfc7396(dict_to_change, dict_reference, key_list=None):
 314     """
 315     Modifies one dictionary with the information of the other following https://tools.ietf.org/html/rfc7396
 316     Basically is a recursive python 'dict_to_change.update(dict_reference)', but a value of None is used to delete.
 317     It implements an extra feature that allows modifying an array. RFC7396 only allows replacing the entire array.
 318     For that, dict_reference should contains a dict with keys starting by "$" with the following meaning:
 319         $[index]    <index> is an integer for targeting a concrete index from dict_to_change array. If the value is None
 320                     the element of the array is deleted, otherwise it is edited.
 321         $+[index]   The value is inserted at this <index>. A value of None has not sense and an exception is raised.
 322         $+          The value is appended at the end. A value of None has not sense and an exception is raised.
 323         $val        It looks for all the items in the array dict_to_change equal to <val>. <val> is evaluated as yaml,
 324                     that is, numbers are taken as type int, true/false as boolean, etc. Use quotes to force string.
 325                     Nothing happens if no match is found. If the value is None the matched elements are deleted.
 326         $key: val   In case a dictionary is passed in yaml format, if looks for all items in the array dict_to_change
 327                     that are dictionaries and contains this <key> equal to <val>. Several keys can be used by yaml
 328                     format '{key: val, key: val, ...}'; and all of them must match. Nothing happens if no match is
 329                     found. If value is None the matched items are deleted, otherwise they are edited.
 330         $+val       If no match if found (see '$val'), the value is appended to the array. If any match is found nothing
 331                     is changed. A value of None has not sense.
 332         $+key: val  If no match if found (see '$key: val'), the value is appended to the array. If any match is found
 333                     nothing is changed. A value of None has not sense.
 334     If there are several editions, insertions and deletions; editions and deletions are done first in reverse index
 335         order; then insertions also in reverse index order; and finally appends in any order. So indexes used at
 336         insertions must take into account the deleted items.
 337     :param dict_to_change:  Target dictionary to be changed.
 338     :param dict_reference: Dictionary that contains changes to be applied.
 339     :param key_list: This is used internally for recursive calls. Do not fill this parameter.
 340     :return: none or raises and exception only at array modification when there is a bad format or conflict.
 341     """
 342     def _deep_update_array(array_to_change, _dict_reference, _key_list):
 343         to_append = {}
 344         to_insert_at_index = {}
 345         values_to_edit_delete = {}
 346         indexes_to_edit_delete = []
 347         array_edition = None
 348         _key_list.append("")
 349         for k in _dict_reference:
 350             _key_list[-1] = str(k)
 351             if not isinstance(k, str) or not k.startswith("$"):
 352                 if array_edition is True:
 353                     raise DbException("Found array edition (keys starting with '$') and pure dictionary edition in the"
 354                                       " same dict at '{}'".format(":".join(_key_list[:-1])))
 355                 array_edition = False
 356                 continue
 357             else:
 358                 if array_edition is False:
 359                     raise DbException("Found array edition (keys starting with '$') and pure dictionary edition in the"
 360                                       " same dict at '{}'".format(":".join(_key_list[:-1])))
 361                 array_edition = True
 362             insert = False
 363             indexes = []  # indexes to edit or insert
 364             kitem = k[1:]
 365             if kitem.startswith('+'):
 366                 insert = True
 367                 kitem = kitem[1:]
 368                 if _dict_reference[k] is None:
 369                     raise DbException("A value of None has not sense for insertions at '{}'".format(
 370                         ":".join(_key_list)))
 371
 372             if kitem.startswith('[') and kitem.endswith(']'):
 373                 try:
 374                     index = int(kitem[1:-1])
 375                     if index < 0:
 376                         index += len(array_to_change)
 377                     if index < 0:
 378                         index = 0  # skip outside index edition
 379                     indexes.append(index)
 380                 except Exception:
 381                     raise DbException("Wrong format at '{}'. Expecting integer index inside quotes".format(
 382                         ":".join(_key_list)))
 383             elif kitem:
 384                 # match_found_skip = False
 385                 try:
 386                     filter_in = yaml.safe_load(kitem)
 387                 except Exception:
 388                     raise DbException("Wrong format at '{}'. Expecting '$<yaml-format>'".format(":".join(_key_list)))
 389                 if isinstance(filter_in, dict):
 390                     for index, item in enumerate(array_to_change):
 391                         for filter_k, filter_v in filter_in.items():
 392                             if not isinstance(item, dict) or filter_k not in item or item[filter_k] != filter_v:
 393                                 break
 394                         else:  # match found
 395                             if insert:
 396                                 # match_found_skip = True
 397                                 insert = False
 398                                 break
 399                             else:
 400                                 indexes.append(index)
 401                 else:
 402                     index = 0
 403                     try:
 404                         while True:  # if not match a ValueError exception will be raise
 405                             index = array_to_change.index(filter_in, index)
 406                             if insert:
 407                                 # match_found_skip = True
 408                                 insert = False
 409                                 break
 410                             indexes.append(index)
 411                             index += 1
 412                     except ValueError:
 413                         pass
 414
 415                 # if match_found_skip:
 416                 #     continue
 417             elif not insert:
 418                 raise DbException("Wrong format at '{}'. Expecting '$+', '$[<index]' or '$[<filter>]'".format(
 419                     ":".join(_key_list)))
 420             for index in indexes:
 421                 if insert:
 422                     if index in to_insert_at_index and to_insert_at_index[index] != _dict_reference[k]:
 423                         # Several different insertions on the same item of the array
 424                         raise DbException("Conflict at '{}'. Several insertions on same array index {}".format(
 425                             ":".join(_key_list), index))
 426                     to_insert_at_index[index] = _dict_reference[k]
 427                 else:
 428                     if index in indexes_to_edit_delete and values_to_edit_delete[index] != _dict_reference[k]:
 429                         # Several different editions on the same item of the array
 430                         raise DbException("Conflict at '{}'. Several editions on array index {}".format(
 431                             ":".join(_key_list), index))
 432                     indexes_to_edit_delete.append(index)
 433                     values_to_edit_delete[index] = _dict_reference[k]
 434             if not indexes:
 435                 if insert:
 436                     to_append[k] = _dict_reference[k]
 437                 # elif _dict_reference[k] is not None:
 438                 #     raise DbException("Not found any match to edit in the array, or wrong format at '{}'".format(
 439                 #         ":".join(_key_list)))
 440
 441         # edition/deletion is done before insertion
 442         indexes_to_edit_delete.sort(reverse=True)
 443         for index in indexes_to_edit_delete:
 444             _key_list[-1] = str(index)
 445             try:
 446                 if values_to_edit_delete[index] is None:  # None->Anything
 447                     try:
 448                         del (array_to_change[index])
 449                     except IndexError:
 450                         pass  # it is not consider an error if this index does not exist
 451                 elif not isinstance(values_to_edit_delete[index], dict):  # NotDict->Anything
 452                     array_to_change[index] = deepcopy(values_to_edit_delete[index])
 453                 elif isinstance(array_to_change[index], dict):  # Dict->Dict
 454                     deep_update_rfc7396(array_to_change[index], values_to_edit_delete[index], _key_list)
 455                 else:  # Dict->NotDict
 456                     if isinstance(array_to_change[index], list):  # Dict->List. Check extra array edition
 457                         if _deep_update_array(array_to_change[index], values_to_edit_delete[index], _key_list):
 458                             continue
 459                     array_to_change[index] = deepcopy(values_to_edit_delete[index])
 460                     # calling deep_update_rfc7396 to delete the None values
 461                     deep_update_rfc7396(array_to_change[index], values_to_edit_delete[index], _key_list)
 462             except IndexError:
 463                 raise DbException("Array edition index out of range at '{}'".format(":".join(_key_list)))
 464
 465         # insertion with indexes
 466         to_insert_indexes = list(to_insert_at_index.keys())
 467         to_insert_indexes.sort(reverse=True)
 468         for index in to_insert_indexes:
 469             array_to_change.insert(index, to_insert_at_index[index])
 470
 471         # append
 472         for k, insert_value in to_append.items():
 473             _key_list[-1] = str(k)
 474             insert_value_copy = deepcopy(insert_value)
 475             if isinstance(insert_value_copy, dict):
 476                 # calling deep_update_rfc7396 to delete the None values
 477                 deep_update_rfc7396(insert_value_copy, insert_value, _key_list)
 478             array_to_change.append(insert_value_copy)
 479
 480         _key_list.pop()
 481         if array_edition:
 482             return True
 483         return False
 484
 485     if key_list is None:
 486         key_list = []
 487     key_list.append("")
 488     for k in dict_reference:
 489         key_list[-1] = str(k)
 490         if dict_reference[k] is None:   # None->Anything
 491             if k in dict_to_change:
 492                 del dict_to_change[k]
 493         elif not isinstance(dict_reference[k], dict):  # NotDict->Anything
 494             dict_to_change[k] = deepcopy(dict_reference[k])
 495         elif k not in dict_to_change:  # Dict->Empty
 496             dict_to_change[k] = deepcopy(dict_reference[k])
 497             # calling deep_update_rfc7396 to delete the None values
 498             deep_update_rfc7396(dict_to_change[k], dict_reference[k], key_list)
 499         elif isinstance(dict_to_change[k], dict):  # Dict->Dict
 500             deep_update_rfc7396(dict_to_change[k], dict_reference[k], key_list)
 501         else:       # Dict->NotDict
 502             if isinstance(dict_to_change[k], list):  # Dict->List. Check extra array edition
 503                 if _deep_update_array(dict_to_change[k], dict_reference[k], key_list):
 504                     continue
 505             dict_to_change[k] = deepcopy(dict_reference[k])
 506             # calling deep_update_rfc7396 to delete the None values
 507             deep_update_rfc7396(dict_to_change[k], dict_reference[k], key_list)
 508     key_list.pop()
 509
 510
 511 def deep_update(dict_to_change, dict_reference):
 512     """ Maintained for backward compatibility. Use deep_update_rfc7396 instead"""
 513     return deep_update_rfc7396(dict_to_change, dict_reference)