Backend Configuration

Relevant source files

The following files were used as context for generating this wiki page:

• README.md
• backend/.env.example
• backend/database.py
• backend/main.py
• backend/settings.py
• backend/services/ai_service.py
• backend/utils/webhooks.py

Introduction

The backend configuration for the QA Dashboard is managed primarily through environment variables, providing a clear separation between code and configuration. This system allows for flexible deployment across different environments (development, production) without code changes. The configuration handles database connections, security credentials for JWT, application behavior (like debug mode), and integrations with external services such as AI-powered suggestions and webhook notifications.

All configuration settings are centralized and loaded using Pydantic's BaseSettings in backend/settings.py. This ensures that settings are validated and type-checked upon application startup. The primary source for these settings is a .env file in the backend directory, with backend/.env.example serving as a template.

Sources: backend/settings.py, backend/.env.example, README.md:105-123

Environment Variables

The application relies on a .env file in the backend directory to configure its core components. The backend/.env.example file provides a template for all required variables.

Sources: backend/.env.example, README.md:105-123

The following diagram illustrates how environment variables from the .env file are loaded by the Settings class and distributed to various modules within the backend application.

Configuration Table

This table details all the environment variables used by the backend.

Variable	Description	Default Value	Source File Usage
DB_HOST	The hostname of the PostgreSQL database (e.g., AWS RDS endpoint).	localhost	settings.py:17
DB_PORT	The port number for the PostgreSQL database.	5432	settings.py:18
DB_NAME	The name of the database to connect to.	qa_dashboard	settings.py:19
DB_USER	The username for database authentication.	postgres	settings.py:20
DB_PASSWORD	The password for database authentication.	password	settings.py:21
API_HOST	The host address the FastAPI application binds to.	0.0.0.0	settings.py:26
API_PORT	The port the FastAPI application runs on.	8000	settings.py:27
DEBUG	Toggles debug mode for the application, enabling features like SQLAlchemy query echoing.	True	settings.py:28, database.py:16
SECRET_KEY	A secret key used for signing JWT tokens. Must be changed in production.	your-secret-key...	settings.py:31
JWT_ALGORITHM	The algorithm used for JWT encoding and decoding.	HS256	settings.py:34
JWT_EXPIRATION_HOURS	The duration (in hours) for which a JWT token is valid.	24	settings.py:35
WEBHOOK_URL	The endpoint URL for sending webhook notifications (e.g., for new questions).	None	settings.py:38, utils/webhooks.py:6
OPENAI_API_KEY	API key for OpenAI (optional, for Langchain).	None	README.md:126
LANGCHAIN_API_KEY	API key for Langchain services (optional).	None	README.md:127
GOOGLE_API_KEY	API key for Google's Generative AI (Gemini). Used by the AI service.	None	services/ai_service.py:19

Sources: backend/.env.example, backend/settings.py, backend/services/ai_service.py:19, backend/utils/webhooks.py:6

Core Application Configuration

Settings Management (settings.py)

The backend/settings.py file uses Pydantic's BaseSettings to define and load all configuration variables from the environment. This provides a single, type-safe source of truth for all settings.

The Settings class automatically constructs the DATABASE_URL from its constituent parts (DB_HOST, DB_USER, etc.).

# backend/settings.py:9-23
class Settings(BaseSettings):
    # ...
    DB_HOST: str = "localhost"
    DB_PORT: int = 5432
    DB_NAME: str = "qa_dashboard"
    DB_USER: str = "postgres"
    DB_PASSWORD: str = "password"

    DATABASE_URL: str = Field(
        default_factory=lambda: f"postgresql+psycopg2://{settings.DB_USER}:{settings.DB_PASSWORD}@{settings.DB_HOST}:{settings.DB_PORT}/{settings.DB_NAME}"
    )

Sources: backend/settings.py:9-23

Database Connection (database.py)

The database connection is established using SQLAlchemy's create_engine. It retrieves the fully constructed DATABASE_URL from the settings object. The DEBUG setting is used to toggle SQL query logging (echo=settings.DEBUG).

# backend/database.py:14-18
engine = create_engine(
    settings.DATABASE_URL,
    echo=settings.DEBUG,
    pool_pre_ping=True,
)

Sources: backend/database.py:14-18

The following diagram shows the sequence of events during application startup to establish a database connection.

External Service Configuration

AI Service (ai_service.py)

The AI service for generating suggested answers is configured via the GOOGLE_API_KEY environment variable. If this key is not provided, the service operates in a "mock mode," returning a placeholder response instead of making a real API call. This allows the application to function without a valid AI service subscription.

The _initialize method within the AIService class handles this logic.

# backend/services/ai_service.py:18-29
def _initialize(self):
    self.api_key = os.getenv("GOOGLE_API_KEY")
    self.mock_mode = False
    self.llm = None

    if not self.api_key:
        logger.warning("GOOGLE_API_KEY not found. AIService will run in MOCK mode.")
        self.mock_mode = True
    else:
        try:
            self.llm = ChatGoogleGenerativeAI(...)
            logger.info("AIService initialized with Gemini.")
        except Exception as e:
            # ...
            self.mock_mode = True

Sources: backend/services/ai_service.py:18-29

Webhook Notifications (webhooks.py)

The system can send notifications to an external service via webhooks. This is configured using the WEBHOOK_URL environment variable. If the WEBHOOK_URL is not set, the send_webhook_notification function will return False immediately, effectively disabling the feature.

# backend/utils/webhooks.py:5-8
async def send_webhook_notification(event_type: str, data: dict) -> bool:
    """Send webhook notification to external service"""
    if not settings.WEBHOOK_URL:
        return False

Sources: backend/utils/webhooks.py:5-8, backend/settings.py:38