Kubs

PUBNUB_CONFIG.md

@@ -28,7 +28,7 @@ The blockchain application uses PubNub for real-time peer-to-peer communication
 
 1. **Copy the secrets template:**
    ```bash
-   cp env.example .env
+   cp backend/config/env.example backend/config/.env
    ```
 
 2. **Edit secrets.env and add your keys:**

README.md

@@ -1,110 +1 @@
-## Python, JS, & React | Build a Blockchain & Cryptocurrency
-
-![Course Logo](python_blockchain_logo.png)
-
-**The course is designed to help you achieve three main goals:**
-- Learn Python and Backend Web Development.
-- Build a Blockchain and Cryptocurrency Project that you can add to your portfolio.
-- Learn JavaScript, Frontend Web Development, React.js, and React Hooks.
-
-The course's main project is to build a blockchain and cryptocurrency. With a blockchain and cryptocurrency system as the main goal, you will go through a course journey that starts with backend development using Python. Then, you will transaction to frontend web development with JavaScript, React.js, and React Hooks.
-
-Check out the course: https://www.udemy.com/course/python-js-react-blockchain/?referralCode=9051A01550E782315B77
-
-**Here's an overview of the overall course journey:**
-- Get an introduction of the Python Fundamentals.
-- Begin building the Blockchain Application with Python.
-- Test the Application using Pytest.
-- Incorporate the crucial concept of Proof of Work into the Blockchain.
-- Enhance the application to prepare for networking.
-- Create the Blockchain network using Flask and Pub/Sub.
-- Integrate the Cryptocurrency, building Wallets, Keys, and Transactions.
-- Extend the network implementation with the cryptocurrency.
-- Transition from Python to JavaScript with a "From Python to JavaScript" introduction.
-- Establish frontend web development skills and begin coding with React.js.
-- Create the frontend portion for the blockchain portion of the system.
-- Complete the frontend by building a UI for the cryptocurrency portion of the system.
-
-**In addition, here are the skills that you'll gain from the course:**
-- How to build a blockchain and cryptocurrency system from scratch.
-- The fundamentals of python - data structures, object-oriented programming, modules, and more.
-- The ins and outs of hashing and sha256.
-- Encoding and decoding in utf-8.
-- Testing Python applications with pytest.
-- Python virtual environments.
-- The concept of proof of work, and how it pertains to mining blocks.
-- Conversion between hexadecimal to binary.
-- HTTP APIs and requests.
-- How to create APIs with Python Flask.
-- The publish/subscribe pattern to set up networks.
-- When to apply the concepts of serialization and deserialization.
-- Public/private keypairs and generating data signatures.
-- The fundamentals of JavaScript.
-- Frontend web development and how web applications are constructed.
-- The core concepts of React and React hooks.
-- How the React engine works under the hood, and how React applies hooks.
-- CORS - and how to get over the CORS error properly.
-- How to build a pagination system.
-
-***
-
-#### Command Reference
-
-**Activate the virtual environment**
-```
-source blockchain-env/bin/activate
-```
-
-**Install all packages**
-```
-pip3 install -r requirements.txt
-```
-
-**Run the tests**
-
-Make sure to activate the virtual environment.
-
-```
-python3 -m pytest backend/tests
-```
-
-**Run the application and API**
-
-Make sure to activate the virtual environment.
-
-```
-python3 -m backend.app
-```
-
-**Run a peer instance**
-
-Make sure to activate the virtual environment.
-Choose a unique PUBNUB_USER_ID per peer.
-
-```
-export PEER=True && export PUBNUB_USER_ID=blockchain-peer-1 && python3 -m backend.app
-```
-
-**Run the frontend**
-
-In the frontend directory:
-```
-npm run start
-```
-
-**Seed the backend with data**
-
-Make sure to activate the virtual environment.
-
-```
-export SEED_DATA=True && python3 -m backend.app
-```
-
-** PubNub Configuration**
-
-This application uses PubNub for real-time peer-to-peer communication between blockchain nodes. **You must configure PubNub to run the application.**
-
-**See [PUBNUB_CONFIG.md](PUBNUB_CONFIG.md) for detailed setup instructions.**
-
-1. Get free PubNub keys at [https://www.pubnub.com/](https://www.pubnub.com/)
-2. copy `backend/env.example` to `backend/.env` and configure it with your keys.
+# TODO

backend/Dockerfile

@@ -0,0 +1,17 @@
+FROM python:3.11-slim
+
+RUN apt-get update && apt-get install curl -y
+
+ENV PYTHONUNBUFFERED=1
+
+WORKDIR /app
+
+COPY requirements.txt .
+
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY backend/ /app/backend/
+
+EXPOSE 5050
+
+CMD ["python", "-m", "backend.app"]

backend/app/__init__.py

@@ -1,167 +0,0 @@
-import os
-import requests
-import random
-import threading
-import time
-from pathlib import Path
-from dotenv import load_dotenv
-
-# Load environment variables FIRST, before any other backend imports
-env_path = Path(__file__).parent.parent / '.env'
-load_dotenv(dotenv_path=env_path)
-
-from flask import Flask, jsonify, request, Response
-from flask_cors import CORS
-import json
-
-from backend.blockchain.blockchain import Blockchain
-from backend.wallet.wallet import Wallet
-from backend.wallet.transaction import Transaction
-from backend.wallet.transaction_pool import TransactionPool
-from backend.pubsub import PubSub
-
-app = Flask(__name__)
-CORS(app, resources={ r'/*': { 'origins': 'http://localhost:3000' } })
-
-def json_response(data, status=200):
-    """
-    Create a JSON response that preserves large integers.
-    Flask's default jsonify converts large ints to floats, which breaks
-    cryptographic signatures. This function ensures integers are preserved.
-    """
-    return Response(
-        json.dumps(data, separators=(',', ':')),
-        status=status,
-        mimetype='application/json'
-    )
-blockchain = Blockchain()
-wallet = Wallet(blockchain)
-transaction_pool = TransactionPool()
-pubsub = PubSub(blockchain, transaction_pool)
-
-@app.route('/')
-def route_default():
-    return 'Welcome to the blockchain'
-
-@app.route('/blockchain')
-def route_blockchain():
-    return json_response(blockchain.to_json())
-
-@app.route('/blockchain/range')
-def route_blockchain_range():
-    # http://localhost:5050/blockchain/range?start=2&end=5
-    start = int(request.args.get('start'))
-    end = int(request.args.get('end'))
-
-    return jsonify(blockchain.to_json()[::-1][start:end])
-
-@app.route('/blockchain/length')
-def route_blockchain_length():
-    return jsonify(len(blockchain.chain))
-
-@app.route('/blockchain/mine')
-def route_blockchain_mine():
-    transaction_data = transaction_pool.transaction_data()
-    transaction_data.append(Transaction.reward_transaction(wallet).to_json())
-    blockchain.add_block(transaction_data)
-    block = blockchain.chain[-1]
-    pubsub.broadcast_block(block)
-    transaction_pool.clear_blockchain_transactions(blockchain)
-
-    return json_response(block.to_json())
-
-@app.route('/wallet/transact', methods=['POST'])
-def route_wallet_transact():
-    transaction_data = request.get_json()
-    transaction = transaction_pool.existing_transaction(wallet.address)
-
-    if transaction:
-        transaction.update(
-            wallet,
-            transaction_data['recipient'],
-            transaction_data['amount']
-        )
-    else:
-        transaction = Transaction(
-            wallet,
-            transaction_data['recipient'],
-            transaction_data['amount']
-        )
-
-    pubsub.broadcast_transaction(transaction)
-    transaction_pool.set_transaction(transaction)
-
-    return jsonify(transaction.to_json())
-
-@app.route('/wallet/info')
-def route_wallet_info():
-    return jsonify({ 'address': wallet.address, 'balance': wallet.balance })
-
-@app.route('/known-addresses')
-def route_known_addresses():
-    known_addresses = set()
-
-    for block in blockchain.chain:
-        for transaction in block.data:
-            known_addresses.update(transaction['output'].keys())
-
-    return jsonify(list(known_addresses))
-
-@app.route('/transactions')
-def route_transactions():
-    return jsonify(transaction_pool.transaction_data())
-
-ROOT_PORT = 5050
-PORT = ROOT_PORT
-# In Docker, use service name supplied by an env variable instead of localhost
-root_host = os.environ.get('ROOT_HOST', 'localhost')
-
-if os.environ.get('PEER') == 'True':
-    PORT = random.randint(5051, 6000)
-
-    result = requests.get(f'http://{root_host}:{ROOT_PORT}/blockchain')
-    result_blockchain = Blockchain.from_json(result.json())
-
-    try:
-        blockchain.replace_chain(result_blockchain.chain)
-        print('\n -- Successfully synchronized the local chain')
-    except Exception as e:
-        print(f'\n -- Error synchronizing: {e}')
-
-if os.environ.get('SEED_DATA') == 'True':
-    for i in range(10):
-        blockchain.add_block([
-            Transaction(Wallet(), Wallet().address, random.randint(2, 50)).to_json(),
-            Transaction(Wallet(), Wallet().address, random.randint(2, 50)).to_json()
-        ])
-
-    for i in range(3):
-        transaction = Transaction(Wallet(), Wallet().address, random.randint(2, 50))
-        pubsub.broadcast_transaction(transaction)
-        transaction_pool.set_transaction(transaction)
-
-def poll_root_blockchain():
-    poll_interval = int(os.environ.get('POLL_INTERVAL', '15'))
-    root_host = os.environ.get('ROOT_HOST', 'localhost')
-
-    print(f'\n -- Starting polling thread for {root_host}:{ROOT_PORT} every {poll_interval}s')
-
-    while True:
-        try:
-            result = requests.get(f'http://{root_host}:{ROOT_PORT}/blockchain')
-            result_blockchain = Blockchain.from_json(result.json())
-            blockchain.replace_chain(result_blockchain.chain)
-            print(f'\n -- Successfully polled blockchain from {root_host}')
-        except Exception as e:
-            print(f'\n -- Error polling root blockchain: {e}')
-
-        time.sleep(poll_interval)
-
-if os.environ.get('POLL_ROOT') == 'True':
-    # Start polling in a background daemon thread so it doesn't block Flask
-    polling_thread = threading.Thread(target=poll_root_blockchain, daemon=True)
-    polling_thread.start()
-
-if __name__ == "__main__":
-    app.run(host="0.0.0.0", port=PORT, debug=True)
-

backend/app/__main__.py

@@ -1,5 +1,58 @@
-from backend.app import app, PORT
+"""
+Application entry point.
+Initializes and runs the Flask application with graceful shutdown handling.
+"""
+import sys
+import signal
+import time
 
+from backend.app.logging import logger
+from backend.app.factory import create_app
+from backend.app.context import app_context
+from backend.app.polling import start_polling_thread, shutdown_event
+from backend.config import AppConfig
+
+
+# Start the polling thread if configured
+polling_thread = start_polling_thread(app_context.blockchain)
+
+# Create the Flask application
+app = create_app()
+
+
+# ------------------------------
+# Graceful shutdown
+# ------------------------------
+def shutdown(signum, frame):
+    """
+    Handle shutdown signals (SIGTERM, SIGINT) gracefully.
+    Stops PubSub, polling thread, and cleans up resources.
+    """
+    logger.info("Received shutdown signal — exiting...")
+
+    # Stop PubSub
+    if app_context.pubsub:
+        logger.info("Stopping PubSub")
+        app_context.pubsub.stop()
+
+    # Stop polling thread
+    shutdown_event.set()
+    if polling_thread and polling_thread.is_alive():
+        logger.info("Waiting for polling thread to finish...")
+        polling_thread.join(timeout=5)
+
+    time.sleep(0.5)
+    logger.info("Cleanup complete. Exiting.")
+    sys.exit(0)
+
+signal.signal(signal.SIGTERM, shutdown)
+signal.signal(signal.SIGINT, shutdown)
+
+# ------------------------------
+# Run the Flask app
+# ------------------------------
 if __name__ == "__main__":
-    app.run(host="0.0.0.0", port=PORT, debug=True)
+    port = AppConfig.get_port()
+    logger.info(f"Starting blockchain node on port {port}")
 
+    app.run(host="0.0.0.0", port=port)