From b1d5d45eefacb7c37308d2f39568f58a7792239f Mon Sep 17 00:00:00 2001
From: Philip Wafula <philipwafula2@gmail.com>
Date: Tue, 29 Jun 2021 10:49:25 +0000
Subject: [PATCH] Philip/db session management

---
 apps/cic-ussd/cic_ussd/db/enum.py             |   9 +
 apps/cic-ussd/cic_ussd/db/models/account.py   |  29 +--
 apps/cic-ussd/cic_ussd/operations.py          | 110 ++++++++----
 apps/cic-ussd/cic_ussd/phone_number.py        |  14 --
 apps/cic-ussd/cic_ussd/processor.py           | 168 +++++++++++-------
 apps/cic-ussd/cic_ussd/requests.py            |  25 ++-
 .../runnable/daemons/cic_user_server.py       |  16 +-
 .../runnable/daemons/cic_user_ussd_server.py  |  10 +-
 .../cic_ussd/state_machine/logic/balance.py   |   5 +-
 .../cic_ussd/state_machine/logic/menu.py      |  16 +-
 .../cic_ussd/state_machine/logic/pin.py       |  48 ++---
 .../cic_ussd/state_machine/logic/sms.py       |   6 +-
 .../state_machine/logic/transaction.py        |  65 ++++---
 .../cic_ussd/state_machine/logic/user.py      |  65 ++++---
 .../cic_ussd/state_machine/logic/validator.py |   8 +-
 apps/cic-ussd/cic_ussd/validator.py           |  29 ++-
 16 files changed, 370 insertions(+), 253 deletions(-)
 create mode 100644 apps/cic-ussd/cic_ussd/db/enum.py

diff --git a/apps/cic-ussd/cic_ussd/db/enum.py b/apps/cic-ussd/cic_ussd/db/enum.py
new file mode 100644
index 00000000..cb9761d3
--- /dev/null
+++ b/apps/cic-ussd/cic_ussd/db/enum.py
@@ -0,0 +1,9 @@
+# standard import
+from enum import IntEnum
+
+
+class AccountStatus(IntEnum):
+    PENDING = 1
+    ACTIVE = 2
+    LOCKED = 3
+    RESET = 4
diff --git a/apps/cic-ussd/cic_ussd/db/models/account.py b/apps/cic-ussd/cic_ussd/db/models/account.py
index 18f5e370..1e073625 100644
--- a/apps/cic-ussd/cic_ussd/db/models/account.py
+++ b/apps/cic-ussd/cic_ussd/db/models/account.py
@@ -1,19 +1,13 @@
 # standard imports
-from enum import IntEnum
-
-# third party imports
-from sqlalchemy import Column, Integer, String
 
 # local imports
+from cic_ussd.db.enum import AccountStatus
 from cic_ussd.db.models.base import SessionBase
 from cic_ussd.encoder import check_password_hash, create_password_hash
 
-
-class AccountStatus(IntEnum):
-    PENDING = 1
-    ACTIVE = 2
-    LOCKED = 3
-    RESET = 4
+# third party imports
+from sqlalchemy import Column, Integer, String
+from sqlalchemy.orm.session import Session
 
 
 class Account(SessionBase):
@@ -30,6 +24,21 @@ class Account(SessionBase):
     account_status = Column(Integer)
     preferred_language = Column(String)
 
+    @staticmethod
+    def get_by_phone_number(phone_number: str, session: Session):
+        """Retrieves an account from a phone number.
+        :param phone_number: The E164 format of a phone number.
+        :type phone_number:str
+        :param session:
+        :type session:
+        :return: An account object.
+        :rtype: Account
+        """
+        session = SessionBase.bind_session(session=session)
+        account = session.query(Account).filter_by(phone_number=phone_number).first()
+        SessionBase.release_session(session=session)
+        return account
+
     def __init__(self, blockchain_address, phone_number):
         self.blockchain_address = blockchain_address
         self.phone_number = phone_number
diff --git a/apps/cic-ussd/cic_ussd/operations.py b/apps/cic-ussd/cic_ussd/operations.py
index 5f2ca7a2..bd0e7476 100644
--- a/apps/cic-ussd/cic_ussd/operations.py
+++ b/apps/cic-ussd/cic_ussd/operations.py
@@ -6,11 +6,13 @@ import logging
 import celery
 import i18n
 from cic_eth.api.api_task import Api
+from sqlalchemy.orm.session import Session
 from tinydb.table import Document
 from typing import Optional
 
 # local imports
 from cic_ussd.db.models.account import Account
+from cic_ussd.db.models.base import SessionBase
 from cic_ussd.db.models.ussd_session import UssdSession
 from cic_ussd.db.models.task_tracker import TaskTracker
 from cic_ussd.menu.ussd_menu import UssdMenu
@@ -22,15 +24,18 @@ from cic_ussd.validator import check_known_user, validate_response_type
 logg = logging.getLogger()
 
 
-def add_tasks_to_tracker(task_uuid):
-    """
-    This function takes tasks spawned over api interfaces and records their creation time for tracking.
+def add_tasks_to_tracker(session, task_uuid: str):
+    """This function takes tasks spawned over api interfaces and records their creation time for tracking.
+    :param session:
+    :type session:
     :param task_uuid: The uuid for an initiated task.
     :type task_uuid: str
     """
+    session = SessionBase.bind_session(session=session)
     task_record = TaskTracker(task_uuid=task_uuid)
-    TaskTracker.session.add(task_record)
-    TaskTracker.session.commit()
+    session.add(task_record)
+    session.flush()
+    SessionBase.release_session(session=session)
 
 
 def define_response_with_content(headers: list, response: str) -> tuple:
@@ -95,6 +100,7 @@ def create_or_update_session(
         service_code: str,
         user_input: str,
         current_menu: str,
+        session,
         session_data: Optional[dict] = None) -> InMemoryUssdSession:
     """
     Handles the creation or updating of session as necessary.
@@ -108,12 +114,15 @@ def create_or_update_session(
     :type user_input: str
     :param current_menu: Menu name that is currently being displayed on the ussd session
     :type current_menu: str
+    :param session:
+    :type session:
     :param session_data: Any additional data that was persisted during the user's interaction with the system.
     :type session_data: dict.
     :return: ussd session object
     :rtype: InMemoryUssdSession
     """
-    existing_ussd_session = UssdSession.session.query(UssdSession).filter_by(
+    session = SessionBase.bind_session(session=session)
+    existing_ussd_session = session.query(UssdSession).filter_by(
         external_session_id=external_session_id).first()
 
     if existing_ussd_session:
@@ -132,20 +141,25 @@ def create_or_update_session(
             current_menu=current_menu,
             session_data=session_data
         )
+    SessionBase.release_session(session=session)
     return ussd_session
 
 
-def get_account_status(phone_number) -> str:
+def get_account_status(phone_number, session: Session) -> str:
     """Get the status of a user's account.
     :param phone_number: The phone number to be checked.
     :type phone_number: str
+    :param session:
+    :type session:
     :return: The user account status.
     :rtype: str
     """
-    user = Account.session.query(Account).filter_by(phone_number=phone_number).first()
-    status = user.get_account_status()
-    Account.session.add(user)
-    Account.session.commit()
+    session = SessionBase.bind_session(session=session)
+    account = Account.get_by_phone_number(phone_number=phone_number, session=session)
+    status = account.get_account_status()
+    session.add(account)
+    session.flush()
+    SessionBase.release_session(session=session)
 
     return status
 
@@ -165,6 +179,7 @@ def initiate_account_creation_request(chain_str: str,
                                       external_session_id: str,
                                       phone_number: str,
                                       service_code: str,
+                                      session,
                                       user_input: str) -> str:
     """This function issues a task to create a blockchain account on cic-eth. It then creates a record of the ussd
     session corresponding to the creation of the account and returns a response denoting that the user's account is
@@ -177,6 +192,8 @@ def initiate_account_creation_request(chain_str: str,
     :type phone_number: str
     :param service_code: The service code dialed.
     :type service_code: str
+    :param session:
+    :type session:
     :param user_input: The input entered by the user.
     :type user_input: str
     :return: A response denoting that the account is being created.
@@ -190,7 +207,7 @@ def initiate_account_creation_request(chain_str: str,
     creation_task_id = cic_eth_api.create_account().id
 
     # record task initiation time
-    add_tasks_to_tracker(task_uuid=creation_task_id)
+    add_tasks_to_tracker(task_uuid=creation_task_id, session=session)
 
     # cache account creation data
     cache_account_creation_task_id(phone_number=phone_number, task_id=creation_task_id)
@@ -204,6 +221,7 @@ def initiate_account_creation_request(chain_str: str,
         phone=phone_number,
         service_code=service_code,
         current_menu=current_menu.get('name'),
+        session=session,
         user_input=user_input)
 
     # define response to relay to user
@@ -268,12 +286,14 @@ def cache_account_creation_task_id(phone_number: str, task_id: str):
     redis_cache.persist(name=task_id)
 
 
-def process_current_menu(ussd_session: Optional[dict], user: Account, user_input: str) -> Document:
+def process_current_menu(account: Account, session: Session, ussd_session: Optional[dict], user_input: str) -> Document:
     """This function checks user input and returns a corresponding ussd menu
     :param ussd_session: An in db ussd session object.
     :type ussd_session: UssdSession
-    :param user: A user object.
-    :type user: Account
+    :param account: A account object.
+    :type account: Account
+    :param session:
+    :type session:
     :param user_input: The user's input.
     :type user_input: str
     :return: An in memory ussd menu object.
@@ -285,7 +305,13 @@ def process_current_menu(ussd_session: Optional[dict], user: Account, user_input
     else:
         # get current state
         latest_input = get_latest_input(user_input=user_input)
-        current_menu = process_request(ussd_session=ussd_session, user_input=latest_input, user=user)
+        session = SessionBase.bind_session(session=session)
+        current_menu = process_request(
+            account=account,
+            session=session,
+            ussd_session=ussd_session,
+            user_input=latest_input)
+        SessionBase.release_session(session=session)
     return current_menu
 
 
@@ -294,6 +320,7 @@ def process_menu_interaction_requests(chain_str: str,
                                       phone_number: str,
                                       queue: str,
                                       service_code: str,
+                                      session,
                                       user_input: str) -> str:
     """This function handles requests intended for interaction with ussd menu, it checks whether a user matching the
     provided phone number exists and in the absence of which it creates an account for the user.
@@ -308,25 +335,29 @@ def process_menu_interaction_requests(chain_str: str,
     :type queue: str
     :param service_code: The service dialed by the user making the request.
     :type service_code: str
+    :param session:
+    :type session:
     :param user_input: The inputs entered by the user.
     :type user_input: str
     :return: A response based on the request received.
     :rtype: str
     """
     # check whether the user exists
-    if not check_known_user(phone=phone_number):
+    if not check_known_user(phone_number=phone_number, session=session):
         response = initiate_account_creation_request(chain_str=chain_str,
                                                      external_session_id=external_session_id,
                                                      phone_number=phone_number,
                                                      service_code=service_code,
+                                                     session=session,
                                                      user_input=user_input)
 
     else:
-        # get user
-        user = Account.session.query(Account).filter_by(phone_number=phone_number).first()
+        # get account
+        session = SessionBase.bind_session(session=session)
+        account = Account.get_by_phone_number(phone_number=phone_number, session=session)
 
         # retrieve and cache user's metadata
-        blockchain_address = user.blockchain_address
+        blockchain_address = account.blockchain_address
         s_query_person_metadata = celery.signature(
             'cic_ussd.tasks.metadata.query_person_metadata',
             [blockchain_address]
@@ -334,24 +365,25 @@ def process_menu_interaction_requests(chain_str: str,
         s_query_person_metadata.apply_async(queue='cic-ussd')
 
         # find any existing ussd session
-        existing_ussd_session = UssdSession.session.query(UssdSession).filter_by(
-            external_session_id=external_session_id).first()
+        existing_ussd_session = session.query(UssdSession).filter_by(external_session_id=external_session_id).first()
 
         # validate user inputs
         if existing_ussd_session:
             current_menu = process_current_menu(
+                account=account,
+                session=session,
                 ussd_session=existing_ussd_session.to_json(),
-                user=user,
                 user_input=user_input
             )
         else:
             current_menu = process_current_menu(
+                account=account,
+                session=session,
                 ussd_session=None,
-                user=user,
                 user_input=user_input
             )
 
-        last_ussd_session = retrieve_most_recent_ussd_session(phone_number=user.phone_number)
+        last_ussd_session = retrieve_most_recent_ussd_session(phone_number=account.phone_number, session=session)
 
         if last_ussd_session:
             # create or update the ussd session as appropriate
@@ -361,6 +393,7 @@ def process_menu_interaction_requests(chain_str: str,
                 service_code=service_code,
                 user_input=user_input,
                 current_menu=current_menu.get('name'),
+                session=session,
                 session_data=last_ussd_session.session_data
             )
         else:
@@ -369,15 +402,17 @@ def process_menu_interaction_requests(chain_str: str,
                 phone=phone_number,
                 service_code=service_code,
                 user_input=user_input,
-                current_menu=current_menu.get('name')
+                current_menu=current_menu.get('name'),
+                session=session
             )
 
         # define appropriate response
         response = custom_display_text(
+            account=account,
             display_key=current_menu.get('display_key'),
             menu_name=current_menu.get('name'),
+            session=session,
             ussd_session=ussd_session.to_json(),
-            user=user
         )
 
     # check that the response from the processor is valid
@@ -386,21 +421,26 @@ def process_menu_interaction_requests(chain_str: str,
 
     # persist session to db
     persist_session_to_db_task(external_session_id=external_session_id, queue=queue)
+    SessionBase.release_session(session=session)
 
     return response
 
 
-def reset_pin(phone_number: str) -> str:
+def reset_pin(phone_number: str, session: Session) -> str:
     """Reset account status from Locked to Pending.
     :param phone_number: The phone number belonging to the account to be unlocked.
     :type phone_number: str
+    :param session:
+    :type session:
     :return: The status of the pin reset.
     :rtype: str
     """
-    user = Account.session.query(Account).filter_by(phone_number=phone_number).first()
-    user.reset_account_pin()
-    Account.session.add(user)
-    Account.session.commit()
+    session = SessionBase.bind_session(session=session)
+    account = Account.get_by_phone_number(phone_number=phone_number, session=session)
+    account.reset_account_pin()
+    session.add(account)
+    session.flush()
+    SessionBase.release_session(session=session)
 
     response = f'Pin reset for user {phone_number} is successful!'
     return response
@@ -438,11 +478,13 @@ def update_ussd_session(
     return session
 
 
-def save_to_in_memory_ussd_session_data(queue: str, session_data: dict, ussd_session: dict):
+def save_to_in_memory_ussd_session_data(queue: str, session: Session, session_data: dict, ussd_session: dict):
     """This function is used to save information to the session data attribute of a ussd session object in the redis
     cache.
     :param queue: The queue on which the celery task should run.
     :type queue: str
+    :param session:
+    :type session:
     :param session_data: A dictionary containing data for a specific ussd session in redis that needs to be saved
     temporarily.
     :type session_data: dict
@@ -473,7 +515,7 @@ def save_to_in_memory_ussd_session_data(queue: str, session_data: dict, ussd_ses
         service_code=in_redis_ussd_session.get('service_code'),
         user_input=in_redis_ussd_session.get('user_input'),
         current_menu=in_redis_ussd_session.get('state'),
+        session=session,
         session_data=session_data
     )
     persist_session_to_db_task(external_session_id=external_session_id, queue=queue)
-
diff --git a/apps/cic-ussd/cic_ussd/phone_number.py b/apps/cic-ussd/cic_ussd/phone_number.py
index 7556709f..1fc94f6f 100644
--- a/apps/cic-ussd/cic_ussd/phone_number.py
+++ b/apps/cic-ussd/cic_ussd/phone_number.py
@@ -33,19 +33,5 @@ def process_phone_number(phone_number: str, region: str):
 
     return parsed_phone_number
 
-
-def get_user_by_phone_number(phone_number: str) -> Optional[Account]:
-    """This function queries the database for a user based on the provided phone number.
-    :param phone_number: A valid phone number.
-    :type phone_number: str
-    :return: A user object matching a given phone number
-    :rtype: Account|None
-    """
-    # consider adding region to user's metadata
-    phone_number = process_phone_number(phone_number=phone_number, region=E164Format.region)
-    user = Account.session.query(Account).filter_by(phone_number=phone_number).first()
-    return user
-
-
 class Support:
     phone_number = None
diff --git a/apps/cic-ussd/cic_ussd/processor.py b/apps/cic-ussd/cic_ussd/processor.py
index adf81f12..a7d515a3 100644
--- a/apps/cic-ussd/cic_ussd/processor.py
+++ b/apps/cic-ussd/cic_ussd/processor.py
@@ -2,25 +2,26 @@
 import datetime
 import logging
 import json
-import re
 from typing import Optional
 
 # third party imports
-import celery
 from sqlalchemy import desc
 from cic_eth.api import Api
+from sqlalchemy.orm.session import Session
 from tinydb.table import Document
 
 # local imports
 from cic_ussd.account import define_account_tx_metadata, retrieve_account_statement
 from cic_ussd.balance import BalanceManager, compute_operational_balance, get_cached_operational_balance
 from cic_ussd.chain import Chain
-from cic_ussd.db.models.account import AccountStatus, Account
+from cic_ussd.db.models.account import Account
+from cic_ussd.db.models.base import SessionBase
 from cic_ussd.db.models.ussd_session import UssdSession
-from cic_ussd.error import MetadataNotFoundError, SeppukuError
+from cic_ussd.db.enum import AccountStatus
+from cic_ussd.error import SeppukuError
 from cic_ussd.menu.ussd_menu import UssdMenu
 from cic_ussd.metadata import blockchain_address_to_metadata_pointer
-from cic_ussd.phone_number import get_user_by_phone_number, Support
+from cic_ussd.phone_number import Support
 from cic_ussd.redis import cache_data, create_cached_data_key, get_cached_data
 from cic_ussd.state_machine import UssdStateMachine
 from cic_ussd.conversions import to_wei, from_wei
@@ -62,47 +63,48 @@ def retrieve_token_symbol(chain_str: str = Chain.spec.__str__()):
             raise SeppukuError(f'Could not retrieve default token for: {chain_str}')
 
 
-def process_pin_authorization(display_key: str, user: Account, **kwargs) -> str:
-    """
-    This method provides translation for all ussd menu entries that follow the pin authorization pattern.
+def process_pin_authorization(account: Account, display_key: str, **kwargs) -> str:
+    """This method provides translation for all ussd menu entries that follow the pin authorization pattern.
+    :param account: The account in a running USSD session.
+    :type account: Account
     :param display_key: The path in the translation files defining an appropriate ussd response
     :type display_key: str
-    :param user: The user in a running USSD session.
-    :type user: Account
     :param kwargs: Any additional information required by the text values in the internationalization files.
     :type kwargs
     :return: A string value corresponding the ussd menu's text value.
     :rtype: str
     """
     remaining_attempts = 3
-    if user.failed_pin_attempts > 0:
+    if account.failed_pin_attempts > 0:
         return translation_for(
             key=f'{display_key}.retry',
-            preferred_language=user.preferred_language,
-            remaining_attempts=(remaining_attempts - user.failed_pin_attempts)
+            preferred_language=account.preferred_language,
+            remaining_attempts=(remaining_attempts - account.failed_pin_attempts)
         )
     else:
         return translation_for(
             key=f'{display_key}.first',
-            preferred_language=user.preferred_language,
+            preferred_language=account.preferred_language,
             **kwargs
         )
 
 
-def process_exit_insufficient_balance(display_key: str, user: Account, ussd_session: dict):
+def process_exit_insufficient_balance(account: Account, display_key: str, session: Session, ussd_session: dict):
     """This function processes the exit menu letting users their account balance is insufficient to perform a specific
     transaction.
+    :param account: The account requesting access to the ussd menu.
+    :type account: Account
     :param display_key: The path in the translation files defining an appropriate ussd response
     :type display_key: str
-    :param user: The user requesting access to the ussd menu.
-    :type user: Account
+    :param session:
+    :type session:
     :param ussd_session: A JSON serialized in-memory ussd session object
     :type ussd_session: dict
     :return: Corresponding translation text response
     :rtype: str
     """
     # get account balance
-    operational_balance = get_cached_operational_balance(blockchain_address=user.blockchain_address)
+    operational_balance = get_cached_operational_balance(blockchain_address=account.blockchain_address)
 
     # compile response data
     user_input = ussd_session.get('user_input').split('*')[-1]
@@ -112,13 +114,13 @@ def process_exit_insufficient_balance(display_key: str, user: Account, ussd_sess
     token_symbol = retrieve_token_symbol()
 
     recipient_phone_number = ussd_session.get('session_data').get('recipient_phone_number')
-    recipient = get_user_by_phone_number(phone_number=recipient_phone_number)
+    recipient = Account.get_by_phone_number(phone_number=recipient_phone_number, session=session)
 
     tx_recipient_information = define_account_tx_metadata(user=recipient)
 
     return translation_for(
         key=display_key,
-        preferred_language=user.preferred_language,
+        preferred_language=account.preferred_language,
         amount=from_wei(transaction_amount),
         token_symbol=token_symbol,
         recipient_information=tx_recipient_information,
@@ -126,12 +128,14 @@ def process_exit_insufficient_balance(display_key: str, user: Account, ussd_sess
     )
 
 
-def process_exit_successful_transaction(display_key: str, user: Account, ussd_session: dict):
+def process_exit_successful_transaction(account: Account, display_key: str, session: Session, ussd_session: dict):
     """This function processes the exit menu after a successful initiation for a transfer of tokens.
+    :param account: The account requesting access to the ussd menu.
+    :type account: Account
     :param display_key: The path in the translation files defining an appropriate ussd response
     :type display_key: str
-    :param user: The user requesting access to the ussd menu.
-    :type user: Account
+    :param session:
+    :type session:
     :param ussd_session: A JSON serialized in-memory ussd session object
     :type ussd_session: dict
     :return: Corresponding translation text response
@@ -140,13 +144,13 @@ def process_exit_successful_transaction(display_key: str, user: Account, ussd_se
     transaction_amount = to_wei(int(ussd_session.get('session_data').get('transaction_amount')))
     token_symbol = retrieve_token_symbol()
     recipient_phone_number = ussd_session.get('session_data').get('recipient_phone_number')
-    recipient = get_user_by_phone_number(phone_number=recipient_phone_number)
+    recipient = Account.get_by_phone_number(phone_number=recipient_phone_number, session=session)
     tx_recipient_information = define_account_tx_metadata(user=recipient)
-    tx_sender_information = define_account_tx_metadata(user=user)
+    tx_sender_information = define_account_tx_metadata(user=account)
 
     return translation_for(
         key=display_key,
-        preferred_language=user.preferred_language,
+        preferred_language=account.preferred_language,
         transaction_amount=from_wei(transaction_amount),
         token_symbol=token_symbol,
         recipient_information=tx_recipient_information,
@@ -154,13 +158,15 @@ def process_exit_successful_transaction(display_key: str, user: Account, ussd_se
     )
 
 
-def process_transaction_pin_authorization(user: Account, display_key: str, ussd_session: dict):
+def process_transaction_pin_authorization(account: Account, display_key: str, session: Session, ussd_session: dict):
     """This function processes pin authorization where making a transaction is concerned. It constructs a
     pre-transaction response menu that shows the details of the transaction.
-    :param user: The user requesting access to the ussd menu.
-    :type user: Account
+    :param account: The account requesting access to the ussd menu.
+    :type account: Account
     :param display_key: The path in the translation files defining an appropriate ussd response
     :type display_key: str
+    :param session:
+    :type session:
     :param ussd_session: The USSD session determining what user data needs to be extracted and added to the menu's
     text values.
     :type ussd_session: UssdSession
@@ -169,16 +175,16 @@ def process_transaction_pin_authorization(user: Account, display_key: str, ussd_
     """
     # compile response data
     recipient_phone_number = ussd_session.get('session_data').get('recipient_phone_number')
-    recipient = get_user_by_phone_number(phone_number=recipient_phone_number)
+    recipient = Account.get_by_phone_number(phone_number=recipient_phone_number, session=session)
     tx_recipient_information = define_account_tx_metadata(user=recipient)
-    tx_sender_information = define_account_tx_metadata(user=user)
+    tx_sender_information = define_account_tx_metadata(user=account)
 
     token_symbol = retrieve_token_symbol()
     user_input = ussd_session.get('session_data').get('transaction_amount')
     transaction_amount = to_wei(value=int(user_input))
     logg.debug('Requires integration to determine user tokens.')
     return process_pin_authorization(
-        user=user,
+        account=account,
         display_key=display_key,
         recipient_information=tx_recipient_information,
         transaction_amount=from_wei(transaction_amount),
@@ -187,14 +193,12 @@ def process_transaction_pin_authorization(user: Account, display_key: str, ussd_
     )
 
 
-def process_account_balances(user: Account, display_key: str, ussd_session: dict):
+def process_account_balances(user: Account, display_key: str):
     """
     :param user:
     :type user:
     :param display_key:
     :type display_key:
-    :param ussd_session:
-    :type ussd_session:
     :return:
     :rtype:
     """
@@ -295,14 +299,12 @@ def process_display_user_metadata(user: Account, display_key: str):
         )
 
 
-def process_account_statement(user: Account, display_key: str, ussd_session: dict):
+def process_account_statement(user: Account, display_key: str):
     """
     :param user:
     :type user:
     :param display_key:
     :type display_key:
-    :param ussd_session:
-    :type ussd_session:
     :return:
     :rtype:
     """
@@ -404,23 +406,26 @@ def process_start_menu(display_key: str, user: Account):
     )
 
 
-def retrieve_most_recent_ussd_session(phone_number: str) -> UssdSession:
+def retrieve_most_recent_ussd_session(phone_number: str, session: Session) -> UssdSession:
     # get last ussd session based on user phone number
-    last_ussd_session = UssdSession.session\
-        .query(UssdSession)\
+    session = SessionBase.bind_session(session=session)
+    last_ussd_session = session.query(UssdSession)\
         .filter_by(msisdn=phone_number)\
         .order_by(desc(UssdSession.created))\
         .first()
+    SessionBase.release_session(session=session)
     return last_ussd_session
 
 
-def process_request(user_input: str, user: Account, ussd_session: Optional[dict] = None) -> Document:
+def process_request(account: Account, session, user_input: str, ussd_session: Optional[dict] = None) -> Document:
     """This function assesses a request based on the user from the request comes, the session_id and the user's
     input. It determines whether the request translates to a return to an existing session by checking whether the
     provided  session id exists in the database or whether the creation of a new ussd session object is warranted.
     It then returns the appropriate ussd menu text values.
-    :param user: The user requesting access to the ussd menu.
-    :type user: Account
+    :param account: The account requesting access to the ussd menu.
+    :type account: Account
+    :param session:
+    :type session:
     :param user_input: The value a user enters in the ussd menu.
     :type user_input: str
     :param ussd_session: A JSON serialized in-memory ussd session object
@@ -433,11 +438,15 @@ def process_request(user_input: str, user: Account, ussd_session: Optional[dict]
         if user_input == "0":
             return UssdMenu.parent_menu(menu_name=ussd_session.get('state'))
         else:
-            successive_state = next_state(ussd_session=ussd_session, user=user, user_input=user_input)
+            successive_state = next_state(
+                account=account,
+                session=session,
+                ussd_session=ussd_session,
+                user_input=user_input)
             return UssdMenu.find_by_name(name=successive_state)
     else:
-        if user.has_valid_pin():
-            last_ussd_session = retrieve_most_recent_ussd_session(phone_number=user.phone_number)
+        if account.has_valid_pin():
+            last_ussd_session = retrieve_most_recent_ussd_session(phone_number=account.phone_number, session=session)
 
             if last_ussd_session:
                 # get last state
@@ -456,28 +465,30 @@ def process_request(user_input: str, user: Account, ussd_session: Optional[dict]
                 else:
                     return UssdMenu.find_by_name(name=last_state)
         else:
-            if user.failed_pin_attempts >= 3 and user.get_account_status() == AccountStatus.LOCKED.name:
+            if account.failed_pin_attempts >= 3 and account.get_account_status() == AccountStatus.LOCKED.name:
                 return UssdMenu.find_by_name(name='exit_pin_blocked')
-            elif user.preferred_language is None:
+            elif account.preferred_language is None:
                 return UssdMenu.find_by_name(name='initial_language_selection')
             else:
                 return UssdMenu.find_by_name(name='initial_pin_entry')
 
 
-def next_state(ussd_session: dict, user: Account, user_input: str) -> str:
+def next_state(account: Account, session, ussd_session: dict, user_input: str) -> str:
     """This function navigates the state machine based on the ussd session object and user inputs it receives.
     It checks the user input and provides the successive state in the state machine. It then updates the session's
     state attribute with the new state.
+    :param account: The account requesting access to the ussd menu.
+    :type account: Account
+    :param session:
+    :type session:
     :param ussd_session: A JSON serialized in-memory ussd session object
     :type ussd_session: dict
-    :param user: The user requesting access to the ussd menu.
-    :type user: Account
     :param user_input: The value a user enters in the ussd menu.
     :type user_input: str
     :return: A string value corresponding the successive give a specific state in the state machine.
     """
     state_machine = UssdStateMachine(ussd_session=ussd_session)
-    state_machine.scan_data((user_input, ussd_session, user))
+    state_machine.scan_data((user_input, ussd_session, account, session))
     new_state = state_machine.state
 
     return new_state
@@ -492,42 +503,63 @@ def process_exit_invalid_menu_option(display_key: str, preferred_language: str):
 
 
 def custom_display_text(
+        account: Account,
         display_key: str,
         menu_name: str,
-        ussd_session: dict,
-        user: Account) -> str:
+        session: Session,
+        ussd_session: dict) -> str:
     """This function extracts the appropriate session data based on the current menu name. It then inserts them as
     keywords in the i18n function.
+    :param account: The account in a running USSD session.
+    :type account: Account
     :param display_key: The path in the translation files defining an appropriate ussd response
     :type display_key: str
     :param menu_name: The name by which a specific menu can be identified.
     :type menu_name: str
-    :param user: The user in a running USSD session.
-    :type user: Account
+    :param session:
+    :type session:
     :param ussd_session: A JSON serialized in-memory ussd session object
     :type ussd_session: dict
     :return: A string value corresponding the ussd menu's text value.
     :rtype: str
     """
     if menu_name == 'transaction_pin_authorization':
-        return process_transaction_pin_authorization(display_key=display_key, user=user, ussd_session=ussd_session)
+        return process_transaction_pin_authorization(
+            account=account,
+            display_key=display_key,
+            session=session,
+            ussd_session=ussd_session)
     elif menu_name == 'exit_insufficient_balance':
-        return process_exit_insufficient_balance(display_key=display_key, user=user, ussd_session=ussd_session)
+        return process_exit_insufficient_balance(
+            account=account,
+            display_key=display_key,
+            session=session,
+            ussd_session=ussd_session)
     elif menu_name == 'exit_successful_transaction':
-        return process_exit_successful_transaction(display_key=display_key, user=user, ussd_session=ussd_session)
+        return process_exit_successful_transaction(
+            account=account,
+            display_key=display_key,
+            session=session,
+            ussd_session=ussd_session)
     elif menu_name == 'start':
-        return process_start_menu(display_key=display_key, user=user)
+        return process_start_menu(display_key=display_key, user=account)
     elif 'pin_authorization' in menu_name:
-        return process_pin_authorization(display_key=display_key, user=user)
+        return process_pin_authorization(
+            account=account,
+            display_key=display_key,
+            session=session)
     elif 'enter_current_pin' in menu_name:
-        return process_pin_authorization(display_key=display_key, user=user)
+        return process_pin_authorization(
+            account=account,
+            display_key=display_key,
+            session=session)
     elif menu_name == 'account_balances':
-        return process_account_balances(display_key=display_key, user=user, ussd_session=ussd_session)
+        return process_account_balances(display_key=display_key, user=account)
     elif 'transaction_set' in menu_name:
-        return process_account_statement(display_key=display_key, user=user, ussd_session=ussd_session)
+        return process_account_statement(display_key=display_key, user=account)
     elif menu_name == 'display_user_metadata':
-        return process_display_user_metadata(display_key=display_key, user=user)
+        return process_display_user_metadata(display_key=display_key, user=account)
     elif menu_name == 'exit_invalid_menu_option':
-        return process_exit_invalid_menu_option(display_key=display_key, preferred_language=user.preferred_language)
+        return process_exit_invalid_menu_option(display_key=display_key, preferred_language=account.preferred_language)
     else:
-        return translation_for(key=display_key, preferred_language=user.preferred_language)
+        return translation_for(key=display_key, preferred_language=account.preferred_language)
diff --git a/apps/cic-ussd/cic_ussd/requests.py b/apps/cic-ussd/cic_ussd/requests.py
index 8d436f45..897d8539 100644
--- a/apps/cic-ussd/cic_ussd/requests.py
+++ b/apps/cic-ussd/cic_ussd/requests.py
@@ -8,9 +8,12 @@ from urllib.parse import urlparse, parse_qs
 
 # third-party imports
 from sqlalchemy import desc
+from sqlalchemy.orm.session import Session
 
 # local imports
-from cic_ussd.db.models.account import AccountStatus, Account
+from cic_ussd.db.models.account import Account
+from cic_ussd.db.models.base import SessionBase
+from cic_ussd.db.enum import AccountStatus
 from cic_ussd.operations import get_account_status, reset_pin
 from cic_ussd.validator import check_known_user
 
@@ -72,24 +75,26 @@ def get_account_creation_callback_request_data(env: dict) -> tuple:
     return status, task_id, result
 
 
-def process_pin_reset_requests(env: dict, phone_number: str):
+def process_pin_reset_requests(env: dict, phone_number: str, session: Session):
     """This function processes requests that are responsible for the pin reset functionality. It processes GET and PUT
     requests responsible for returning an account's status and
     :param env: A dictionary of values representing data sent on the api.
     :type env: dict
     :param phone_number: The phone of the user whose pin is being reset.
     :type phone_number: str
+    :param session:
+    :type session:
     :return: A response denoting the result of the request to reset the user's pin.
     :rtype: str
     """
-    if not check_known_user(phone=phone_number):
+    if not check_known_user(phone_number=phone_number, session=session):
         return f'No user matching {phone_number} was found.', '404 Not Found'
 
     if get_request_method(env) == 'PUT':
-        return reset_pin(phone_number=phone_number), '200 OK'
+        return reset_pin(phone_number=phone_number, session=session), '200 OK'
 
     if get_request_method(env) == 'GET':
-        status = get_account_status(phone_number=phone_number)
+        status = get_account_status(phone_number=phone_number, session=session)
         response = {
             'status': f'{status}'
         }
@@ -97,16 +102,18 @@ def process_pin_reset_requests(env: dict, phone_number: str):
         return response, '200 OK'
 
 
-def process_locked_accounts_requests(env: dict) -> tuple:
+def process_locked_accounts_requests(env: dict, session: Session) -> tuple:
     """This function authenticates staff requests and returns a serialized JSON formatted list of blockchain addresses
     of accounts for which the PIN has been locked due to too many failed attempts.
     :param env: A dictionary of values representing data sent on the api.
     :type env: dict
+    :param session:
+    :type session:
     :return: A tuple containing a serialized list of blockchain addresses for locked accounts and corresponding message
     for the response.
     :rtype: tuple
     """
-    logg.debug('Authentication requires integration with cic-auth')
+    session = SessionBase.bind_session(session=session)
     response = ''
 
     if get_request_method(env) == 'GET':
@@ -123,12 +130,14 @@ def process_locked_accounts_requests(env: dict) -> tuple:
             else:
                 limit = r[1]
 
-        locked_accounts = Account.session.query(Account.blockchain_address).filter(
+        locked_accounts = session.query(Account.blockchain_address).filter(
             Account.account_status == AccountStatus.LOCKED.value,
             Account.failed_pin_attempts >= 3).order_by(desc(Account.updated)).offset(offset).limit(limit).all()
 
         # convert lists to scalar blockchain addresses
         locked_accounts = [blockchain_address for (blockchain_address, ) in locked_accounts]
+
+        SessionBase.release_session(session=session)
         response = json.dumps(locked_accounts)
         return response, '200 OK'
     return response, '405 Play by the rules'
diff --git a/apps/cic-ussd/cic_ussd/runnable/daemons/cic_user_server.py b/apps/cic-ussd/cic_ussd/runnable/daemons/cic_user_server.py
index 53f633f6..c8df1ccd 100644
--- a/apps/cic-ussd/cic_ussd/runnable/daemons/cic_user_server.py
+++ b/apps/cic-ussd/cic_ussd/runnable/daemons/cic_user_server.py
@@ -36,11 +36,8 @@ logg.debug('config loaded from {}:\n{}'.format(args.c, config))
 # set up db
 data_source_name = dsn_from_config(config)
 SessionBase.connect(data_source_name, pool_size=int(config.get('DATABASE_POOL_SIZE')), debug=config.true('DATABASE_DEBUG'))
-# create session for the life time of http request
-SessionBase.session = SessionBase.create_session()
 
 
-# handle requests from CICADA
 def application(env, start_response):
     """Loads python code for application to be accessible over web server
     :param env: Object containing server and request information
@@ -55,19 +52,24 @@ def application(env, start_response):
     errors_headers = [('Content-Type', 'text/plain'), ('Content-Length', '0')]
     headers = [('Content-Type', 'text/plain')]
 
+    # create session for the life time of http request
+    session = SessionBase.create_session()
+
     if get_request_endpoint(env) == '/pin':
         phone_number = get_query_parameters(env=env, query_name='phoneNumber')
         phone_number = quote_plus(phone_number)
-        response, message = process_pin_reset_requests(env=env, phone_number=phone_number)
+        response, message = process_pin_reset_requests(env=env, phone_number=phone_number, session=session)
         response_bytes, headers = define_response_with_content(headers=errors_headers, response=response)
-        SessionBase.session.close()
+        session.commit()
+        session.close()
         start_response(message, headers)
         return [response_bytes]
 
     # handle requests for locked accounts
-    response, message = process_locked_accounts_requests(env=env)
+    response, message = process_locked_accounts_requests(env=env, session=session)
     response_bytes, headers = define_response_with_content(headers=headers, response=response)
     start_response(message, headers)
-    SessionBase.session.close()
+    session.commit()
+    session.close()
     return [response_bytes]
 
diff --git a/apps/cic-ussd/cic_ussd/runnable/daemons/cic_user_ussd_server.py b/apps/cic-ussd/cic_ussd/runnable/daemons/cic_user_ussd_server.py
index 738127e8..984fb680 100644
--- a/apps/cic-ussd/cic_ussd/runnable/daemons/cic_user_ussd_server.py
+++ b/apps/cic-ussd/cic_ussd/runnable/daemons/cic_user_ussd_server.py
@@ -55,8 +55,6 @@ data_source_name = dsn_from_config(config)
 SessionBase.connect(data_source_name,
                     pool_size=int(config.get('DATABASE_POOL_SIZE')),
                     debug=config.true('DATABASE_DEBUG'))
-# create session for the life time of http request
-SessionBase.session = SessionBase.create_session()
 
 # set up translations
 i18n.load_path.append(config.get('APP_LOCALE_PATH'))
@@ -143,6 +141,9 @@ def application(env, start_response):
     errors_headers = [('Content-Type', 'text/plain'), ('Content-Length', '0')]
     headers = [('Content-Type', 'text/plain')]
 
+    # create session for the life time of http request
+    session = SessionBase.create_session()
+
     if get_request_method(env=env) == 'POST' and get_request_endpoint(env=env) == '/':
 
         if env.get('CONTENT_TYPE') != 'application/x-www-form-urlencoded':
@@ -206,17 +207,20 @@ def application(env, start_response):
                                                      phone_number=phone_number,
                                                      queue=args.q,
                                                      service_code=service_code,
+                                                     session=session,
                                                      user_input=user_input)
 
         response_bytes, headers = define_response_with_content(headers=headers, response=response)
         start_response('200 OK,', headers)
-        SessionBase.session.close()
+        session.commit()
+        session.close()
         return [response_bytes]
 
     else:
         logg.error('invalid query {}'.format(env))
         for r in env:
             logg.debug('{}: {}'.format(r, env))
+        session.close()
         start_response('405 Play by the rules', errors_headers)
         return []
 
diff --git a/apps/cic-ussd/cic_ussd/state_machine/logic/balance.py b/apps/cic-ussd/cic_ussd/state_machine/logic/balance.py
index 899ff346..64f1dd61 100644
--- a/apps/cic-ussd/cic_ussd/state_machine/logic/balance.py
+++ b/apps/cic-ussd/cic_ussd/state_machine/logic/balance.py
@@ -3,6 +3,7 @@ import logging
 from typing import Tuple
 
 # third-party imports
+from sqlalchemy.orm.session import Session
 
 # local imports
 from cic_ussd.db.models.account import Account
@@ -10,11 +11,11 @@ from cic_ussd.db.models.account import Account
 logg = logging.getLogger(__file__)
 
 
-def process_mini_statement_request(state_machine_data: Tuple[str, dict, Account]):
+def process_mini_statement_request(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function compiles a brief statement of a user's last three inbound and outbound transactions and send the
     same as a message on their selected avenue for notification.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: str
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     logg.debug('This section requires integration with cic-eth. (The last 6 transactions would be sent as an sms.)')
diff --git a/apps/cic-ussd/cic_ussd/state_machine/logic/menu.py b/apps/cic-ussd/cic_ussd/state_machine/logic/menu.py
index a1889ce5..bac773b9 100644
--- a/apps/cic-ussd/cic_ussd/state_machine/logic/menu.py
+++ b/apps/cic-ussd/cic_ussd/state_machine/logic/menu.py
@@ -16,7 +16,7 @@ def menu_one_selected(state_machine_data: Tuple[str, dict, Account]) -> bool:
     :return: A user input's match with '1'
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user_input == '1'
 
 
@@ -27,7 +27,7 @@ def menu_two_selected(state_machine_data: Tuple[str, dict, Account]) -> bool:
     :return: A user input's match with '2'
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user_input == '2'
 
 
@@ -38,7 +38,7 @@ def menu_three_selected(state_machine_data: Tuple[str, dict, Account]) -> bool:
     :return: A user input's match with '3'
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user_input == '3'
 
 
@@ -50,7 +50,7 @@ def menu_four_selected(state_machine_data: Tuple[str, dict, Account]) -> bool:
     :return: A user input's match with '4'
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user_input == '4'
 
 
@@ -62,7 +62,7 @@ def menu_five_selected(state_machine_data: Tuple[str, dict, Account]) -> bool:
     :return: A user input's match with '5'
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user_input == '5'
 
 
@@ -74,7 +74,7 @@ def menu_six_selected(state_machine_data: Tuple[str, dict, Account]) -> bool:
     :return: A user input's match with '6'
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user_input == '6'
 
 
@@ -86,7 +86,7 @@ def menu_zero_zero_selected(state_machine_data: Tuple[str, dict, Account]) -> bo
     :return: A user input's match with '00'
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user_input == '00'
 
 
@@ -98,5 +98,5 @@ def menu_ninety_nine_selected(state_machine_data: Tuple[str, dict, Account]) ->
     :return: A user input's match with '99'
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user_input == '99'
diff --git a/apps/cic-ussd/cic_ussd/state_machine/logic/pin.py b/apps/cic-ussd/cic_ussd/state_machine/logic/pin.py
index 5f51e602..9419d248 100644
--- a/apps/cic-ussd/cic_ussd/state_machine/logic/pin.py
+++ b/apps/cic-ussd/cic_ussd/state_machine/logic/pin.py
@@ -9,11 +9,13 @@ import re
 from typing import Tuple
 
 # third party imports
-import bcrypt
+from sqlalchemy.orm.session import Session
 
 # local imports
-from cic_ussd.db.models.account import AccountStatus, Account
-from cic_ussd.encoder import PasswordEncoder, create_password_hash, check_password_hash
+from cic_ussd.db.models.account import Account
+from cic_ussd.db.models.base import SessionBase
+from cic_ussd.db.enum import AccountStatus
+from cic_ussd.encoder import create_password_hash, check_password_hash
 from cic_ussd.operations import persist_session_to_db_task, create_or_update_session
 from cic_ussd.redis import InMemoryStore
 
@@ -21,7 +23,7 @@ from cic_ussd.redis import InMemoryStore
 logg = logging.getLogger(__file__)
 
 
-def is_valid_pin(state_machine_data: Tuple[str, dict, Account]) -> bool:
+def is_valid_pin(state_machine_data: Tuple[str, dict, Account, Session]) -> bool:
     """This function checks a pin's validity by ensuring it has a length of for characters and the characters are
     numeric.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
@@ -29,7 +31,7 @@ def is_valid_pin(state_machine_data: Tuple[str, dict, Account]) -> bool:
     :return: A pin's validity
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     pin_is_valid = False
     matcher = r'^\d{4}$'
     if re.match(matcher, user_input):
@@ -37,34 +39,34 @@ def is_valid_pin(state_machine_data: Tuple[str, dict, Account]) -> bool:
     return pin_is_valid
 
 
-def is_authorized_pin(state_machine_data: Tuple[str, dict, Account]) -> bool:
+def is_authorized_pin(state_machine_data: Tuple[str, dict, Account, Session]) -> bool:
     """This function checks whether the user input confirming a specific pin matches the initial pin entered.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     :return: A match between two pin values.
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user.verify_password(password=user_input)
 
 
-def is_locked_account(state_machine_data: Tuple[str, dict, Account]) -> bool:
+def is_locked_account(state_machine_data: Tuple[str, dict, Account, Session]) -> bool:
     """This function checks whether a user's account is locked due to too many failed attempts.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     :return: A match between two pin values.
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user.get_account_status() == AccountStatus.LOCKED.name
 
 
-def save_initial_pin_to_session_data(state_machine_data: Tuple[str, dict, Account]):
+def save_initial_pin_to_session_data(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function hashes a pin and stores it in session data.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
 
     # define redis cache entry point
     cache = InMemoryStore.cache
@@ -93,54 +95,56 @@ def save_initial_pin_to_session_data(state_machine_data: Tuple[str, dict, Accoun
         service_code=in_redis_ussd_session.get('service_code'),
         user_input=user_input,
         current_menu=in_redis_ussd_session.get('state'),
+        session=session,
         session_data=session_data
     )
     persist_session_to_db_task(external_session_id=external_session_id, queue='cic-ussd')
 
 
-def pins_match(state_machine_data: Tuple[str, dict, Account]) -> bool:
+def pins_match(state_machine_data: Tuple[str, dict, Account, Session]) -> bool:
     """This function checks whether the user input confirming a specific pin matches the initial pin entered.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     :return: A match between two pin values.
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     initial_pin = ussd_session.get('session_data').get('initial_pin')
-    logg.debug(f'USSD SESSION:  {ussd_session}')
     return check_password_hash(user_input, initial_pin)
 
 
-def complete_pin_change(state_machine_data: Tuple[str, dict, Account]):
+def complete_pin_change(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function persists the user's pin to the database
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
+    session = SessionBase.bind_session(session=session)
     password_hash = ussd_session.get('session_data').get('initial_pin')
     user.password_hash = password_hash
-    Account.session.add(user)
-    Account.session.commit()
+    session.add(user)
+    session.flush()
+    SessionBase.release_session(session=session)
 
 
-def is_blocked_pin(state_machine_data: Tuple[str, dict, Account]) -> bool:
+def is_blocked_pin(state_machine_data: Tuple[str, dict, Account, Session]) -> bool:
     """This function checks whether the user input confirming a specific pin matches the initial pin entered.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     :return: A match between two pin values.
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     return user.get_account_status() == AccountStatus.LOCKED.name
 
 
-def is_valid_new_pin(state_machine_data: Tuple[str, dict, Account]) -> bool:
+def is_valid_new_pin(state_machine_data: Tuple[str, dict, Account, Session]) -> bool:
     """This function checks whether the user's new pin is a valid pin and that it isn't the same as the old one.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     :return: A match between two pin values.
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     is_old_pin = user.verify_password(password=user_input)
     return is_valid_pin(state_machine_data=state_machine_data) and not is_old_pin
diff --git a/apps/cic-ussd/cic_ussd/state_machine/logic/sms.py b/apps/cic-ussd/cic_ussd/state_machine/logic/sms.py
index 517c09e9..6f33a555 100644
--- a/apps/cic-ussd/cic_ussd/state_machine/logic/sms.py
+++ b/apps/cic-ussd/cic_ussd/state_machine/logic/sms.py
@@ -9,15 +9,15 @@ logg = logging.getLogger()
 
 
 def send_terms_to_user_if_required(state_machine_data: Tuple[str, dict, Account]):
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     logg.debug('Requires integration to cic-notify.')
 
 
 def process_mini_statement_request(state_machine_data: Tuple[str, dict, Account]):
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     logg.debug('Requires integration to cic-notify.')
 
 
 def upsell_unregistered_recipient(state_machine_data: Tuple[str, dict, Account]):
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     logg.debug('Requires integration to cic-notify.')
\ No newline at end of file
diff --git a/apps/cic-ussd/cic_ussd/state_machine/logic/transaction.py b/apps/cic-ussd/cic_ussd/state_machine/logic/transaction.py
index b8894103..c2ac5e45 100644
--- a/apps/cic-ussd/cic_ussd/state_machine/logic/transaction.py
+++ b/apps/cic-ussd/cic_ussd/state_machine/logic/transaction.py
@@ -5,13 +5,16 @@ from typing import Tuple
 
 # third party imports
 import celery
+from sqlalchemy.orm.session import Session
 
 # local imports
-from cic_ussd.balance import BalanceManager, compute_operational_balance
+from cic_ussd.balance import compute_operational_balance
 from cic_ussd.chain import Chain
-from cic_ussd.db.models.account import AccountStatus, Account
+from cic_ussd.db.models.account import Account
+from cic_ussd.db.models.base import SessionBase
+from cic_ussd.db.enum import AccountStatus
 from cic_ussd.operations import save_to_in_memory_ussd_session_data
-from cic_ussd.phone_number import get_user_by_phone_number, process_phone_number, E164Format
+from cic_ussd.phone_number import process_phone_number, E164Format
 from cic_ussd.processor import retrieve_token_symbol
 from cic_ussd.redis import create_cached_data_key, get_cached_data
 from cic_ussd.transactions import OutgoingTransactionProcessor
@@ -20,7 +23,7 @@ from cic_ussd.transactions import OutgoingTransactionProcessor
 logg = logging.getLogger(__file__)
 
 
-def is_valid_recipient(state_machine_data: Tuple[str, dict, Account]) -> bool:
+def is_valid_recipient(state_machine_data: Tuple[str, dict, Account, Session]) -> bool:
     """This function checks that a user exists, is not the initiator of the transaction, has an active account status
     and is authorized to perform  standard transactions.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
@@ -28,15 +31,17 @@ def is_valid_recipient(state_machine_data: Tuple[str, dict, Account]) -> bool:
     :return: A user's validity
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     phone_number = process_phone_number(user_input, E164Format.region)
-    recipient = get_user_by_phone_number(phone_number=user_input)
+    session = SessionBase.bind_session(session=session)
+    recipient = Account.get_by_phone_number(phone_number=phone_number, session=session)
+    SessionBase.release_session(session=session)
     is_not_initiator = phone_number != user.phone_number
     has_active_account_status = user.get_account_status() == AccountStatus.ACTIVE.name
     return is_not_initiator and has_active_account_status and recipient is not None
 
 
-def is_valid_transaction_amount(state_machine_data: Tuple[str, dict, Account]) -> bool:
+def is_valid_transaction_amount(state_machine_data: Tuple[str, dict, Account, Session]) -> bool:
     """This function checks that the transaction amount provided is valid as per the criteria for the transaction
     being attempted.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
@@ -44,14 +49,14 @@ def is_valid_transaction_amount(state_machine_data: Tuple[str, dict, Account]) -
     :return: A transaction amount's validity
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     try:
         return int(user_input) > 0
     except ValueError:
         return False
 
 
-def has_sufficient_balance(state_machine_data: Tuple[str, dict, Account]) -> bool:
+def has_sufficient_balance(state_machine_data: Tuple[str, dict, Account, Session]) -> bool:
     """This function checks that the transaction amount provided is valid as per the criteria for the transaction
     being attempted.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
@@ -59,10 +64,7 @@ def has_sufficient_balance(state_machine_data: Tuple[str, dict, Account]) -> boo
     :return: An account balance's validity
     :rtype: bool
     """
-    user_input, ussd_session, user = state_machine_data
-    balance_manager = BalanceManager(address=user.blockchain_address,
-                                     chain_str=Chain.spec.__str__(),
-                                     token_symbol='SRF')
+    user_input, ussd_session, user, session = state_machine_data
     # get cached balance
     key = create_cached_data_key(
         identifier=bytes.fromhex(user.blockchain_address[2:]),
@@ -74,30 +76,37 @@ def has_sufficient_balance(state_machine_data: Tuple[str, dict, Account]) -> boo
     return int(user_input) <= operational_balance
 
 
-def save_recipient_phone_to_session_data(state_machine_data: Tuple[str, dict, Account]):
+def save_recipient_phone_to_session_data(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function saves the phone number corresponding the intended recipients blockchain account.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: str
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
 
     session_data = ussd_session.get('session_data') or {}
-    session_data['recipient_phone_number'] = user_input
+    recipient_phone_number = process_phone_number(phone_number=user_input, region=E164Format.region)
+    session_data['recipient_phone_number'] = recipient_phone_number
 
-    save_to_in_memory_ussd_session_data(queue='cic-ussd', session_data=session_data, ussd_session=ussd_session)
+    save_to_in_memory_ussd_session_data(
+        queue='cic-ussd',
+        session=session,
+        session_data=session_data,
+        ussd_session=ussd_session)
 
 
-def retrieve_recipient_metadata(state_machine_data: Tuple[str, dict, Account]):
+def retrieve_recipient_metadata(state_machine_data: Tuple[str, dict, Account, Session]):
     """
     :param state_machine_data:
     :type state_machine_data:
     :return:
     :rtype:
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
 
-    recipient = get_user_by_phone_number(phone_number=user_input)
+    recipient_phone_number = process_phone_number(phone_number=user_input, region=E164Format.region)
+    recipient = Account.get_by_phone_number(phone_number=recipient_phone_number, session=session)
     blockchain_address = recipient.blockchain_address
+
     # retrieve and cache account's metadata
     s_query_person_metadata = celery.signature(
         'cic_ussd.tasks.metadata.query_person_metadata',
@@ -106,32 +115,36 @@ def retrieve_recipient_metadata(state_machine_data: Tuple[str, dict, Account]):
     s_query_person_metadata.apply_async(queue='cic-ussd')
 
 
-def save_transaction_amount_to_session_data(state_machine_data: Tuple[str, dict, Account]):
+def save_transaction_amount_to_session_data(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function saves the phone number corresponding the intended recipients blockchain account.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: str
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
 
     session_data = ussd_session.get('session_data') or {}
     session_data['transaction_amount'] = user_input
 
-    save_to_in_memory_ussd_session_data(queue='cic-ussd', session_data=session_data, ussd_session=ussd_session)
+    save_to_in_memory_ussd_session_data(
+        queue='cic-ussd',
+        session=session,
+        session_data=session_data,
+        ussd_session=ussd_session)
 
 
-def process_transaction_request(state_machine_data: Tuple[str, dict, Account]):
+def process_transaction_request(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function saves the phone number corresponding the intended recipients blockchain account.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: str
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
 
     # retrieve token symbol
     chain_str = Chain.spec.__str__()
 
     # get user from phone number
     recipient_phone_number = ussd_session.get('session_data').get('recipient_phone_number')
-    recipient = get_user_by_phone_number(phone_number=recipient_phone_number)
+    recipient = Account.get_by_phone_number(phone_number=recipient_phone_number, session=session)
     to_address = recipient.blockchain_address
     from_address = user.blockchain_address
     amount = int(ussd_session.get('session_data').get('transaction_amount'))
diff --git a/apps/cic-ussd/cic_ussd/state_machine/logic/user.py b/apps/cic-ussd/cic_ussd/state_machine/logic/user.py
index d9218845..7c01f971 100644
--- a/apps/cic-ussd/cic_ussd/state_machine/logic/user.py
+++ b/apps/cic-ussd/cic_ussd/state_machine/logic/user.py
@@ -5,12 +5,14 @@ from typing import Tuple
 
 # third-party imports
 import celery
-from cic_types.models.person import Person, generate_metadata_pointer
+from cic_types.models.person import generate_metadata_pointer
 from cic_types.models.person import generate_vcard_from_contact_data, manage_identity_data
+from sqlalchemy.orm.session import Session
 
 # local imports
 from cic_ussd.chain import Chain
 from cic_ussd.db.models.account import Account
+from cic_ussd.db.models.base import SessionBase
 from cic_ussd.error import MetadataNotFoundError
 from cic_ussd.metadata import blockchain_address_to_metadata_pointer
 from cic_ussd.operations import save_to_in_memory_ussd_session_data
@@ -19,15 +21,17 @@ from cic_ussd.redis import get_cached_data
 logg = logging.getLogger(__file__)
 
 
-def change_preferred_language_to_en(state_machine_data: Tuple[str, dict, Account]):
+def change_preferred_language_to_en(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function changes the user's preferred language to english.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
+    session = SessionBase.bind_session(session=session)
     user.preferred_language = 'en'
-    Account.session.add(user)
-    Account.session.commit()
+    session.add(user)
+    session.flush()
+    SessionBase.release_session(session=session)
 
     preferences_data = {
         'preferred_language': 'en'
@@ -40,15 +44,17 @@ def change_preferred_language_to_en(state_machine_data: Tuple[str, dict, Account
     s.apply_async(queue='cic-ussd')
 
 
-def change_preferred_language_to_sw(state_machine_data: Tuple[str, dict, Account]):
+def change_preferred_language_to_sw(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function changes the user's preferred language to swahili.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     """
-    user_input, ussd_session, user = state_machine_data
-    user.preferred_language = 'sw'
-    Account.session.add(user)
-    Account.session.commit()
+    user_input, ussd_session, account, session = state_machine_data
+    session = SessionBase.bind_session(session=session)
+    account.preferred_language = 'sw'
+    session.add(account)
+    session.flush()
+    SessionBase.release_session(session=session)
 
     preferences_data = {
         'preferred_language': 'sw'
@@ -56,20 +62,22 @@ def change_preferred_language_to_sw(state_machine_data: Tuple[str, dict, Account
 
     s = celery.signature(
         'cic_ussd.tasks.metadata.add_preferences_metadata',
-        [user.blockchain_address, preferences_data]
+        [account.blockchain_address, preferences_data]
     )
     s.apply_async(queue='cic-ussd')
 
 
-def update_account_status_to_active(state_machine_data: Tuple[str, dict, Account]):
+def update_account_status_to_active(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function sets user's account to active.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     """
-    user_input, ussd_session, user = state_machine_data
-    user.activate_account()
-    Account.session.add(user)
-    Account.session.commit()
+    user_input, ussd_session, account, session = state_machine_data
+    session = SessionBase.bind_session(session=session)
+    account.activate_account()
+    session.add(account)
+    session.flush()
+    SessionBase.release_session(session=session)
 
 
 def process_gender_user_input(user: Account, user_input: str):
@@ -81,6 +89,7 @@ def process_gender_user_input(user: Account, user_input: str):
     :return:
     :rtype:
     """
+    gender = ""
     if user.preferred_language == 'en':
         if user_input == '1':
             gender = 'Male'
@@ -98,13 +107,13 @@ def process_gender_user_input(user: Account, user_input: str):
     return gender
 
 
-def save_metadata_attribute_to_session_data(state_machine_data: Tuple[str, dict, Account]):
+def save_metadata_attribute_to_session_data(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function saves first name data to the ussd session in the redis cache.
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     """
-    user_input, ussd_session, user = state_machine_data
-
+    user_input, ussd_session, user, session = state_machine_data
+    session = SessionBase.bind_session(session=session)
     # get current menu
     current_state = ussd_session.get('state')
 
@@ -137,7 +146,11 @@ def save_metadata_attribute_to_session_data(state_machine_data: Tuple[str, dict,
         session_data = {
             key: user_input
         }
-    save_to_in_memory_ussd_session_data(queue='cic-ussd', session_data=session_data, ussd_session=ussd_session)
+    save_to_in_memory_ussd_session_data(
+        queue='cic-ussd',
+        session=session,
+        session_data=session_data,
+        ussd_session=ussd_session)
 
 
 def format_user_metadata(metadata: dict, user: Account):
@@ -197,12 +210,12 @@ def format_user_metadata(metadata: dict, user: Account):
     }
 
 
-def save_complete_user_metadata(state_machine_data: Tuple[str, dict, Account]):
+def save_complete_user_metadata(state_machine_data: Tuple[str, dict, Account, Session]):
     """This function persists elements of the user metadata stored in session data
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: tuple
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
 
     # get session data
     metadata = ussd_session.get('session_data')
@@ -218,8 +231,8 @@ def save_complete_user_metadata(state_machine_data: Tuple[str, dict, Account]):
     s_create_person_metadata.apply_async(queue='cic-ussd')
 
 
-def edit_user_metadata_attribute(state_machine_data: Tuple[str, dict, Account]):
-    user_input, ussd_session, user = state_machine_data
+def edit_user_metadata_attribute(state_machine_data: Tuple[str, dict, Account, Session]):
+    user_input, ussd_session, user, session = state_machine_data
     blockchain_address = user.blockchain_address
     key = generate_metadata_pointer(
         identifier=blockchain_address_to_metadata_pointer(blockchain_address=user.blockchain_address),
@@ -269,8 +282,8 @@ def edit_user_metadata_attribute(state_machine_data: Tuple[str, dict, Account]):
     s_edit_person_metadata.apply_async(queue='cic-ussd')
 
 
-def get_user_metadata(state_machine_data: Tuple[str, dict, Account]):
-    user_input, ussd_session, user = state_machine_data
+def get_user_metadata(state_machine_data: Tuple[str, dict, Account, Session]):
+    user_input, ussd_session, user, session = state_machine_data
     blockchain_address = user.blockchain_address
     s_get_user_metadata = celery.signature(
         'cic_ussd.tasks.metadata.query_person_metadata',
diff --git a/apps/cic-ussd/cic_ussd/state_machine/logic/validator.py b/apps/cic-ussd/cic_ussd/state_machine/logic/validator.py
index 2af1e8d3..80747042 100644
--- a/apps/cic-ussd/cic_ussd/state_machine/logic/validator.py
+++ b/apps/cic-ussd/cic_ussd/state_machine/logic/validator.py
@@ -19,7 +19,7 @@ def has_cached_user_metadata(state_machine_data: Tuple[str, dict, Account]):
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: str
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     # check for user metadata in cache
     key = generate_metadata_pointer(
         identifier=blockchain_address_to_metadata_pointer(blockchain_address=user.blockchain_address),
@@ -34,7 +34,7 @@ def is_valid_name(state_machine_data: Tuple[str, dict, Account]):
     :param state_machine_data: A tuple containing user input, a ussd session and user object.
     :type state_machine_data: str
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     name_matcher = "^[a-zA-Z]+$"
     valid_name = re.match(name_matcher, user_input)
     if valid_name:
@@ -50,7 +50,7 @@ def is_valid_gender_selection(state_machine_data: Tuple[str, dict, Account]):
     :return:
     :rtype:
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     selection_matcher = "^[1-2]$"
     if re.match(selection_matcher, user_input):
         return True
@@ -65,6 +65,6 @@ def is_valid_date(state_machine_data: Tuple[str, dict, Account]):
     :return:
     :rtype:
     """
-    user_input, ussd_session, user = state_machine_data
+    user_input, ussd_session, user, session = state_machine_data
     # For MVP this value is defaulting to year
     return len(user_input) == 4 and int(user_input) >= 1900
diff --git a/apps/cic-ussd/cic_ussd/validator.py b/apps/cic-ussd/cic_ussd/validator.py
index 660f2783..a1706f9a 100644
--- a/apps/cic-ussd/cic_ussd/validator.py
+++ b/apps/cic-ussd/cic_ussd/validator.py
@@ -9,6 +9,7 @@ from confini import Config
 
 # local imports
 from cic_ussd.db.models.account import Account
+from cic_ussd.db.models.base import SessionBase
 
 logg = logging.getLogger(__file__)
 
@@ -45,29 +46,21 @@ def check_request_content_length(config: Config, env: dict):
         config.get('APP_MAX_BODY_LENGTH'))
 
 
-def check_known_user(phone: str):
-    """
-    This method attempts to ascertain whether the user already exists and is known to the system.
+def check_known_user(phone_number: str, session):
+    """This method attempts to ascertain whether the user already exists and is known to the system.
     It sends a get request to the platform application and attempts to retrieve the user's data which it persists in
     memory.
-    :param phone: A valid phone number
-    :type phone: str
+    :param phone_number: A valid phone number
+    :type phone_number: str
+    :param session:
+    :type session:
     :return: Is known phone number
     :rtype: boolean
     """
-    user = Account.session.query(Account).filter_by(phone_number=phone).first()
-    return user is not None
-
-
-def check_phone_number(number: str):
-    """
-    Checks whether phone number is present
-    :param number: A valid phone number
-    :type number: str
-    :return: Phone number presence
-    :rtype: boolean
-    """
-    return number is not None
+    session = SessionBase.bind_session(session=session)
+    account = session.query(Account).filter_by(phone_number=phone_number).first()
+    SessionBase.release_session(session=session)
+    return account is not None
 
 
 def check_request_method(env: dict):