Started working on account service and related protocol commands

.env.example

@@ -8,10 +8,6 @@ RESPONSE_TIMEOUT=5
 # within this timeframe
 CLIENT_IDLE_TIMEOUT=60
 
-# A valid port number
-# If not provided or invalid, defaults to 65526
-PORT=65526
-
 # DEBUG, INFO, WARNING, ERROR, CRITICAL are valid
 # If an invalid value is provided, the app defaults to INFO
 VERBOSITY=DEBUG

.gitignore

@@ -168,3 +168,4 @@ cython_debug/
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
 #.idea/
 
+bank.db

src/bank_node/bank_node.py

@@ -95,3 +95,5 @@ class BankNode():
     def cleanup(self):
         self.logger.debug("Closing socket server")
         self.socket_server.close()
+        self.logger.debug("Closing database connection")
+        self.database_manager.cleanup()

src/bank_node/bank_worker.py

@@ -1,23 +1,23 @@
 import socket
 import multiprocessing
 import logging
-from typing import Tuple, Dict
+from typing import Tuple
 import signal
 import sys
 
 from bank_protocol.command_handler import CommandHandler
-from core import Request, Response
+from core import Request, Response, BankNodeConfig
 from core.exceptions import BankNodeError
 
 
 class BankWorker(multiprocessing.Process):
-    def __init__(self, client_socket: socket.socket, client_address: Tuple, config: Dict):
+    def __init__(self, client_socket: socket.socket, client_address: Tuple, config: BankNodeConfig):
         super().__init__()
 
         self.logger = logging.getLogger(__name__)
 
         self.client_socket = client_socket
-        self.client_socket.settimeout(config["client_idle_timeout"])
+        self.client_socket.settimeout(config.client_idle_timeout)
         self.client_address = client_address
 
         self.command_handler = CommandHandler(config)
@@ -65,8 +65,8 @@ class BankWorker(multiprocessing.Process):
                     response = "ER " + e.message + "\n\r"
                     self.client_socket.sendall(response.encode("utf-8"))
                 except socket.error as e:
-                    response = "ER Internal server error\n\r"
                     self.logger.error(e)
+                    response = "ER Internal server error\n\r"
                     break
 
         self.logger.debug("Closing process for %s", self.client_address[0])

src/bank_protocol/exceptions.py

@@ -12,3 +12,21 @@ class InvalidRequest(BankNodeError):
     def __init__(self, message):
         super().__init__(message)
         self.message = message
+
+
+class RequestTimeoutError(BankNodeError):
+    def __init__(self, message):
+        super().__init__(message)
+        self.message = message
+
+
+class HostUnreachableError(BankNodeError):
+    def __init__(self, message):
+        super().__init__(message)
+        self.message = message
+
+
+class NoPortsOpenError(BankNodeError):
+    def __init__(self, message):
+        super().__init__(message)
+        self.message = message

src/bank_protocol/proxy_handler.py

@@ -1,23 +1,37 @@
 import socket
-from typing import Tuple
+import logging
 
-from core import Request, Response
+from core import Request, Response, BankNodeConfig
-from bank_protocol.exceptions import ProxyError
+from bank_protocol.exceptions import RequestTimeoutError, NoPortsOpenError, HostUnreachableError
 
 
 class BankProxy():
-    def __init__(self, request: Request, address: Tuple):
+    def __init__(self, request: Request, address: str, config: BankNodeConfig):
         self.request = request
         self.address = address
+        self.config = config
+
+        self.logger = logging.getLogger(__name__)
 
     def proxy_request(self) -> Response:
+        for port in range(self.config.scan_port_start, self.config.scan_port_end + 1):
+            self.logger.debug("Connecting to port %d", port)
             try:
+                self.config.used_port = port
+                self.__proxy_request(port)
+                return
+            except socket.error as e:
+                if e.errno == 111: # Connection refused
+                    self.logger.debug("Port %d not open", port)
+
+        self.logger.warning("No ports open on the destination host")
+        raise NoPortsOpenError("Destination host has no open ports from range")
+
+    def __proxy_request(self, port):
         with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as client_socket:
-                client_socket.connect(self.address)
+            client_socket.connect((self.address, port))
 
             client_socket.sendall(self.request.as_request())
 
             response = client_socket.recv(1024)
             return response
-        except socket.error as e:
-            raise ProxyError("Proxy error") from e

src/core/__init__.py

@@ -1,7 +1,9 @@
 from .request import *
 from .response import *
+from .config import BankNodeConfig
 
 __all__ = [
     *request.__all__,
-    *response.__all__
+    *response.__all__,
+    *config.__all__
 ]

src/core/config.py

@@ -69,3 +69,6 @@ class BankNodeConfig:
             "scan_port_start": self.scan_port_start,
             "scan_port_end": self.scan_port_end,
         }
+
+
+__all__ = ["BankNodeConfig"]

src/database/database_manager.py

@@ -1,9 +1,9 @@
 import logging
 from typing import Generator
+from contextlib import contextmanager
 
-from sqlalchemy.orm import sessionmaker
+from sqlalchemy.orm import sessionmaker, Session
 from sqlalchemy import create_engine, text
-
 from sqlalchemy.exc import DatabaseError
 
 from database.exceptions import DatabaseConnectionError
@@ -29,13 +29,13 @@ class DatabaseManager():
         self.engine = create_engine('sqlite:///bank.db')
 
         self.Session = sessionmaker(bind=self.engine)
+        self.create_tables()
 
     def create_tables(self):
         self.logger.debug("Creating tables")
         Base.metadata.create_all(self.engine)
 
     def cleanup(self) -> None:
-        self.logger.debug("Closing connection")
         self.engine.dispose()
 
     def test_connection(self) -> bool:
@@ -52,7 +52,8 @@ class DatabaseManager():
         return False
 
     @classmethod
-    def get_session(cls) -> Generator:
+    @contextmanager
+    def get_session(cls) -> Generator[Session]:
         session = cls._instance.Session()
         try:
             yield session

src/database/exceptions.py

@@ -25,4 +25,16 @@ class DuplicateEntryError(DatabaseError):
         self.message = message
 
 
+class NonexistentAccountError(DatabaseError):
+    def __init__(self, message: str):
+        super().__init__(message)
+        self.message = message
+
+
+class OutOfAccountSpaceError(DatabaseError):
+    def __init__(self, message: str):
+        super().__init__(message)
+        self.message = message
+
+
 __all__ = ["DatabaseError", "DatabaseConnectionError", "DuplicateEntryError"]

src/services/account_serice.py

@@ -0,0 +1,47 @@
+from sqlalchemy import func
+
+from models import Account
+from database import DatabaseManager
+from database.exceptions import OutOfAccountSpaceError, NonexistentAccountError
+from utils.constants import MIN_ACCOUNT_NUMBER, MAX_ACCOUNT_NUMBER
+
+
+def get_next_id() -> int:
+    with DatabaseManager.get_session() as session:
+        new_id = session.query(func.max(Account.account_number)).scalar()
+        new_id = new_id if new_id is not None else MIN_ACCOUNT_NUMBER
+
+        if new_id > MAX_ACCOUNT_NUMBER:
+            raise OutOfAccountSpaceError("Too many users already exist, cannot open new account")
+
+        return new_id
+
+
+def create_account() -> int:
+    new_id = get_next_id()
+
+    with DatabaseManager.get_session() as session:
+        new_account = Account(account_number=new_id, balance=0)
+        session.add(new_account)
+        session.commit()
+    return new_id
+
+
+def get_account_balance(account_number: int) -> int:
+    with DatabaseManager.get_session() as session:
+        account: Account = session.query(Account).where(Account.account_number == account_number).one_or_none()
+        if account is NotImplemented:
+            raise NonexistentAccountError(f"Account with number {account_number} doesn't exist")
+
+        return account.balance
+
+def withdraw_from_account():
+    pass
+
+
+def deposit_into_account():
+    pass
+
+
+def delete_account():
+    pass

src/utils/constants.py

@@ -3,3 +3,6 @@ import re
 IP_REGEX = r"^[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}$"
 ACCOUNT_NUMBER_REGEX = r"[0-9]{9}"
 MONEY_AMOUNT_MAXIMUM = (2 ^ 63) - 1
+
+MIN_ACCOUNT_NUMBER = 10_000
+MAX_ACCOUNT_NUMBER = 99_999