Updated code in several modules

03-data-processing/README.md

@@ -80,11 +80,12 @@ Before starting this lesson, please ensure that you have:
     import os
     from sqlalchemy import create_engine, text
 
-    def load_data_to_postgres(input_dir='/data', db_name='weather_data'):
-        db_user = os.getenv('DB_USER', 'your_user')
-        db_password = os.getenv('DB_PASSWORD', 'your_password')
-        db_host = os.getenv('DB_HOST', 'postgres')  # Ensure this is 'postgres' in Docker
-        db_port = os.getenv('DB_PORT', '5432')
+    def load_data_to_postgres(input_dir='/data'):
+        db_name = os.getenv('DB_NAME')
+        db_user = os.getenv('DB_USER')
+        db_password = os.getenv('DB_PASSWORD')
+        db_host = os.getenv('DB_HOST')  # Ensure this is 'postgres' in Docker
+        db_port = os.getenv('DB_PORT')
 
         # Create SQLAlchemy engine
         engine = create_engine(f'postgresql+psycopg2://{db_user}:{db_password}@{db_host}:{db_port}/{db_name}')
@@ -160,11 +161,12 @@ Before starting this lesson, please ensure that you have:
     from sqlalchemy import create_engine, text
     import os
 
-    def transform_and_load_final(db_name='weather_data'):
-        db_user = os.getenv('DB_USER', 'your_user')
-        db_password = os.getenv('DB_PASSWORD', 'your_password')
-        db_host = os.getenv('DB_HOST', 'postgres')  # Ensure this is 'postgres' in Docker
-        db_port = os.getenv('DB_PORT', '5432')
+    def transform_and_load_final():
+        db_name = os.getenv('DB_NAME')
+        db_user = os.getenv('DB_USER')
+        db_password = os.getenv('DB_PASSWORD')
+        db_host = os.getenv('DB_HOST')  # Ensure this is 'postgres' in Docker
+        db_port = os.getenv('DB_PORT')
 
         # Create SQLAlchemy engine
         engine = create_engine(f'postgresql+psycopg2://{db_user}:{db_password}@{db_host}:{db_port}/{db_name}')

04-user-interface/README.md

@@ -100,14 +100,26 @@ Before starting this lesson, please ensure that you have:
 
 8. Finally, open up the file named `.env`.
 
-9. Copy the code below into `.env` and save it.
-    ```text
-    # Database URL for PostgreSQL
-    DATABASE_URL=postgresql+psycopg2://your_user:your_password@postgres/weather_data
+9. Add the following content to the `.env` file:
+
+    ```
+    DB_NAME=weather_data
+    DB_USER=your_user
+    DB_PASSWORD=your_password
+    DB_HOST=postgres
+    DB_PORT=5432
     ```
-    This .env file contains environment variables for our Flask application. It defines the DATABASE_URL, which specifies how to connect to the PostgreSQL database containing our weather data. Using environment variables allows for easy configuration changes without modifying the application code, enhancing the portability and security of our containerized application.
 
-    Note: Make sure to replace 'your_user' and 'your_password' with the actual credentials you set up for your PostgreSQL database in the earlier steps of this workshop.
+    This `.env` file contains key-value pairs for our environment variables:
+
+    - `DB_NAME`: The name of our PostgreSQL database
+    - `DB_USER` and `DB_PASSWORD`: Credentials for accessing the database
+    - `DB_HOST`: Set to `postgres`, which is the service name of our PostgreSQL container
+    - `DB_PORT`: The port on which PostgreSQL is running (default is 5432)
+
+    Using a `.env` file allows us to keep sensitive information out of our version-controlled files and easily change configurations without modifying our Docker Compose file.
+
+    > **Warning:** While .env files are convenient for development, it's important to follow best practices, especially when moving towards production. We're using .env files for simplicity in this workshop, production deployments often require more robust security measures. Take a look at [.env Best Practices](../02-containerized-environment/README.md#env-best-practices) for more guidance.
 
 ## Conclusion
 

flask-app/app.py

@@ -10,14 +10,17 @@
 # Set the Matplotlib backend to Agg
 plt.switch_backend('Agg')
 
-# Load environment variables from .env file
-load_dotenv()
-
 app = Flask(__name__)
 
 # Retrieve the database URL from environment variables
-DATABASE_URL = os.getenv('DATABASE_URL')
-engine = create_engine(DATABASE_URL)
+db_name = os.getenv('DB_NAME')
+db_user = os.getenv('DB_USER')
+db_password = os.getenv('DB_PASSWORD')
+db_host = os.getenv('DB_HOST')  # Ensure this is 'postgres' in Docker
+db_port = os.getenv('DB_PORT')
+
+# Create SQLAlchemy engine
+engine = create_engine(f'postgresql+psycopg2://{db_user}:{db_password}@{db_host}:{db_port}/{db_name}')
 
 @app.route('/')
 def index():
@@ -63,4 +66,4 @@ def plot():
     return send_file(img, mimetype='image/png')
 
 if __name__ == '__main__':
-    app.run(host='0.0.0.0', port=5000)
+    app.run(host='0.0.0.0', port=5000)