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Preparing a Tornado application for deployment

Preparing a Tornado Application for Deployment

Introduction​

In this tutorial, we will cover the key steps to prepare your Tornado application for deployment. Tornado is a Python web framework and asynchronous networking library that helps developers build high performance, real-time web applications.

Step 1: Finalize Your Application Code​

Before you prepare your Tornado application for deployment, ensure that your application code is final and thoroughly tested. Any changes after deployment should be minor and non-breaking.

# Sample Tornado application
import tornado.ioloop
import tornado.web

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Hello, world")

def make_app():
    return tornado.web.Application([
        (r"/", MainHandler),
    ], debug=True)

if __name__ == "__main__":
    app = make_app()
    app.listen(8888)
    tornado.ioloop.IOLoop.current().start()

Here, we have a simple Tornado application. It listens on port 8888 and responds with "Hello, world" on the root route.

Step 2: Remove Debug Mode​

Before you deploy your Tornado application, ensure that debug mode is turned off in your application. Debug mode is great for development but can expose sensitive information in a production environment.

def make_app():
    return tornado.web.Application([
        (r"/", MainHandler),
    ], debug=False)

In the above code, we set debug=False.

Step 3: Set Up Logging​

Logging provides visibility into the behavior of a running app. Tornado uses Python’s built-in logging library.

import logging

if __name__ == "__main__":
    app = make_app()
    app.listen(8888)
    logging.getLogger().setLevel(logging.INFO)
    tornado.ioloop.IOLoop.current().start()

In the above code, we set the logging level to INFO.

Step 4: Configure for Production​

You might need to configure your application differently in production. For example, you might want to listen on a different port, use different database credentials, etc.

import os

def make_app():
    return tornado.web.Application([
        (r"/", MainHandler),
    ], debug=False, autoreload=False, compiled_template_cache=False, static_hash_cache=False)

if __name__ == "__main__":
    app = make_app()
    app.listen(os.environ.get("PORT", 8888))
    logging.getLogger().setLevel(logging.INFO)
    tornado.ioloop.IOLoop.current().start()

In the above code, we added configuration options suitable for a production environment and made the listening port configurable using an environment variable.

Step 5: Bundle Your Application​

Now that your application is ready for deployment, it's time to bundle it up. Python provides several ways to bundle an application, including creating a source distribution, a wheel distribution, or a standalone executable.

Step 6: Test Your Deployment​

Before you deploy your application to production, test the deployment process in a staging environment that closely mirrors your production environment. This helps catch any issues that might not have shown up in the development environment.

Conclusion​

Preparing a Tornado application for deployment involves finalizing your code, removing debug mode, setting up logging, configuring for production, bundling your application, and testing your deployment. By following these steps, you can help ensure a smooth deployment process for your Tornado application.