Nexios

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🛠️ Nexios CLI Guide ​

Nexios provides a powerful command-line interface (CLI) that makes it easy to develop, test, and deploy your applications. This guide will walk you through using the CLI, starting with basic commands and gradually introducing the configuration system.

📦 Installation ​

First, install the Nexios CLI with the cli extra:

bash
pip install nexios[cli]

🎯 Basic Commands ​

bash
# Show help and available commands
nexios --help

# Run a simple application (defaults to main:app on port 8000)
nexios run

# Run in development mode with auto-reload
nexios dev

# List all registered routes
nexios urls

# Check if a specific route exists
nexios ping /api/status

# Start an interactive Python shell with your app loaded
nexios shell

⚙️ Configuration with nexios.config.py ​

As your project grows, you'll want to customize how Nexios runs your application. This is where nexios.config.py comes in.

Creating a Basic Config ​

Create a nexios.config.py file in your project root. Here's a minimal example:

python
# nexios.config.py
app_path = "main:app"  # Path to your FastAPI/Starlette app
port = 8000           # Default port
host = "127.0.0.1"    # Default host

How Configuration Works ​

  1. Automatic Loading: When you run any nexios command, it automatically looks for nexios.config.py in your current directory.
  2. Simple Variables: Configuration is done through Python variables, making it easy to understand and modify.
  3. Type Safety: The CLI validates your configuration when your application starts.

Common Configuration Options ​

Here are the most frequently used configuration options:

  • app_path (required): Path to your application instance in module:app format
  • host: The host to bind to (default: "127.0.0.1")
  • port: The port to run on (default: 8000)
  • reload: Enable auto-reload in development (default: False in production, True in nexios dev)

Development vs Production ​

Development Configuration ​

python
# nexios.config.py
app_path = "src.main:app"
host = "127.0.0.1"
port = 5000
reload = True  # Enable auto-reload
log_level = "debug"

Production Configuration ​

python
# nexios.config.py
app_path = "myapp.main:app"
host = "0.0.0.0"
port = 80
workers = 4  # For production servers that support workers
log_level = "info"

🔧 How Commands Use the Config ​

Each Nexios command uses the configuration in different ways:

nexios run ​

  • Uses: app_path, host, port, server, workers, log_level
  • Example: nexios run --port 8080 (overrides config port)

nexios dev ​

  • Always enables reload and debug mode
  • Uses same config as run but with development defaults

nexios urls and nexios ping ​

  • Uses: app_path to load your application
  • Example: nexios urls shows all routes

🏭 Advanced Configuration ​

Custom Server Command ​

For complete control, you can specify a custom command:

python
# nexios.config.py
custom_command = "gunicorn -w 4 -k uvicorn.workers.UvicornWorker myapp.main:app"

Environment Variables ​

You can use environment variables in your config:

python
import os

app_path = os.getenv("APP_PATH", "main:app")
port = int(os.getenv("PORT", "8000"))

Multiple Environments ​

Handle different environments in one config file:

python
import os

env = os.getenv("ENV", "development")

if env == "production":
    app_path = "myapp.main:app"
    host = "0.0.0.0"
    port = 80
    log_level = "warning"
else:  # development
    app_path = "main:app"
    host = "127.0.0.1"
    port = 8000
    reload = True
    log_level = "debug"
nexios urls
nexios ping /about

2. Production (Gunicorn) ​

python
# nexios.config.py
app_path = "src.main:app"
server = "gunicorn"
port = 80
host = "0.0.0.0"
workers = 8
log_level = "info"
bash
nexios run

3. Custom Command ​

python
# nexios.config.py
app_path = "myproject.main:app"
custom_command = "gunicorn -w 4 -b 0.0.0.0:9000 myproject.main:app"
bash
nexios run

⚡ Advanced: app vs. app_path ​

  • app_path (recommended): The string path to your app instance, e.g. main:app. Used by all CLI commands to dynamically import your app.
  • app (optional): If you want to use your app instance directly in Python scripts or for advanced CLI scripting, you can define it in nexios.config.py. Otherwise, it is not needed.

🛠️ Troubleshooting & Migration ​

  • Error: Could not find app module: Make sure app_path is set in nexios.config.py and points to a valid module:variable.
  • Error: Could not load the app instance: Check that your app_path is correct and the module is importable.
  • Switching from old config: Just move your options to plain variables in nexios.config.py and set app_path.
  • Custom server logic: Use custom_command for full control.

📋 Best Practices ​

  • Always set app_path in your config for maximum compatibility.
  • Use server = "gunicorn" for production, uvicorn for development.
  • Use nexios dev for local development with auto-reload and debug.
  • Use nexios shell for interactive debugging and testing.
  • Keep your config expressive and version-controlled.

📚 Further Reading ​

With this setup, Nexios CLI is fully driven by your project config, making development, debugging, and deployment seamless and consistent.