Configuration Management

Nexios applications are configured by passing settings directly to the app or middleware:

from nexios import NexiosApp

app = NexiosApp()

# Configure the app
app.config.port = 8000
app.config.debug = True

You can also set configuration values directly:

from nexios import NexiosApp

app = NexiosApp()
app.config.database_url = "postgresql://user:pass@localhost/dbname"

# Access configuration values
print(app.config.port)          # Output: 8000 (default)
print(app.config.debug)          # Output: False (default)
print(app.config.database_url)    # Output: postgresql://user:pass@localhost/dbname

For middleware-specific config, pass settings directly:

from nexios import NexiosApp
from nexios.middleware.cors import CorsConfig, CORSMiddleware

app = NexiosApp()
app.add_middleware(
    CORSMiddleware(
        config=CorsConfig(
            allow_origins=["https://example.com"],
            allow_methods=["GET", "POST"]
        )
    )
)

Configuration is immutable by default:

# Configuration is immutable by default
try:
    app.config.port = 9000  # This will raise an error
except AttributeError:
    print("Configuration is immutable")

Global Configuration Access

The framework provides global configuration management through app.config, allowing you to access configuration from anywhere in your application:

from nexios import NexiosApp

app = NexiosApp()
app.config.port = 8000
app.config.debug = True
app.config.database_url = "postgresql://user:pass@localhost/dbname"

# Access configuration from startup handler
@app.on_startup
async def startup_handler():
    print(f"Starting server on port {app.config.port}")
    print(f"Debug mode: {app.config.debug}")
    print(f"Database URL: {app.config.database_url}")

# Get configuration from any handler
@app.get("/config")
async def get_config_handler(request, response):
    return response.json({
        "port": app.config.port,
        "debug": app.config.debug,
        "database_url": app.config.database_url
    })

# Access configuration from utility functions
def get_database_connection():
    return create_connection(app.config.database_url)

⚠️Warning

You can access the configuration through app.config from any module in your application. However, if you modify the configuration in one test without resetting it, other tests running in parallel or subsequent tests might fail unexpectedly. Always reset the configuration in your test teardown or use fixtures to ensure a clean state for each test.

Environment-Based Configuration

Using Environment Variables

Environment variables are the most common way to configure applications in different environments:

import os
from nexios import NexiosApp

app = NexiosApp()
app.config.debug = os.getenv("DEBUG", "False").lower() == "true"
app.config.secret_key = os.getenv("SECRET_KEY", "default-secret-key")
app.config.database_url = os.getenv("DATABASE_URL", "sqlite:///app.db")
app.config.redis_url = os.getenv("REDIS_URL", "redis://localhost:6379")
app.config.port = int(os.getenv("PORT", "8000"))
app.config.host = os.getenv("HOST", "127.0.0.1")
app.config.log_level = os.getenv("LOG_LEVEL", "INFO")

Using .env Files

For development, you can use .env files to manage environment variables:

from nexios import NexiosApp
from nexios.config import load_env
import os

# Load environment variables from .env file
load_env()

app = NexiosApp()
app.config.debug = os.getenv("DEBUG", "False").lower() == "true"
app.config.secret_key = os.getenv("SECRET_KEY")
app.config.database_url = os.getenv("DATABASE_URL")
app.config.redis_url = os.getenv("REDIS_URL")
app.config.port = int(os.getenv("PORT", "8000"))
app.config.host = os.getenv("HOST", "127.0.0.1")

Example .env file:

# Development Environment
DEBUG=true
SECRET_KEY=dev-secret-key-change-in-production
DATABASE_URL=postgresql://user:pass@localhost/dev_db
REDIS_URL=redis://localhost:6379
PORT=8000
HOST=127.0.0.1
LOG_LEVEL=DEBUG

Advanced Configuration Patterns

Nested Configuration

For complex applications, you can use nested configuration structures directly on app.config:

from nexios import NexiosApp

app = NexiosApp()

# Server config
app.config.server_host = "127.0.0.1"
app.config.server_port = 8000
app.config.server_workers = 4

# Database config
app.config.database_url = "postgresql://user:pass@localhost/dbname"
app.config.database_pool_size = 20
app.config.database_max_overflow = 30
app.config.database_timeout = 30

# Redis config
app.config.redis_url = "redis://localhost:6379"
app.config.redis_pool_size = 10
app.config.redis_timeout = 5

# Security config
app.config.secret_key = "your-secret-key"
app.config.session_timeout = 3600
app.config.csrf_enabled = True

# Logging config
app.config.logging_level = "INFO"
app.config.logging_format = "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
app.config.logging_file = "app.log"

# Access nested configuration
print(app.config.server_host)      # 127.0.0.1
print(app.config.database_pool_size)   # 20
print(app.config.csrf_enabled)        # True

This comprehensive configuration guide covers all aspects of managing configuration in Nexios applications. The configuration system is designed to be flexible, secure, and easy to use while providing the power to handle complex configuration scenarios across different environments.