How to Host Flask App on Server

Hello Dev,

Welcome to this journal article that guides you through the process of hosting Flask app on a server. Flask is a popular Python web framework for building web applications, and hosting it on a server is an essential step for making it available to the users.

Prerequisites

Before we dive into the hosting process, let’s make sure we have all the prerequisites ready.

Python and Flask

The first prerequisite is to have Python and Flask installed on your local machine. You can download and install Python from the official website, and then use pip to install Flask by executing the following command:

$ pip install Flask

Virtual Environment

It is always a good practice to use a virtual environment to keep the dependencies isolated. You can create a virtual environment using the following command:

$ python -m venv env

After creating the virtual environment, activate it using the following command:

$ source env/bin/activate

Codebase

You should have the codebase of your Flask app ready to deploy. Make sure all the necessary files and dependencies are included in the codebase.

Choosing a Server Provider

The next step is to choose a server provider that suits your requirements. There are many server providers available in the market, such as AWS, Google Cloud, Heroku, etc. In this article, we will be using AWS as our server provider.

Creating an AWS Account

If you don’t have an AWS account, you can create one by following these steps:

1. Go to the AWS home page and click on the “Create an AWS Account” button.
2. Fill out the required information and choose the payment plan that suits your needs.
3. Verify your email address and phone number.
4. Enter your payment information and confirm your identity.

Creating an EC2 Instance

EC2 is a web service that provides resizable compute capacity in the cloud. We will be using EC2 to host our Flask app.

Launch Instance

To launch an EC2 instance, follow these steps:

1. Login to your AWS account.
2. Click on the “EC2” link under the “Compute” section.
3. Click on the “Launch Instance” button.
4. Choose your preferred Amazon Machine Image (AMI).
5. Select the instance type that suits your needs.
6. Configure the instance details, such as the number of instances, network settings, etc.
7. Add storage to your instance.
8. Add tags to your instance for better organization.
9. Configure the security group to allow inbound traffic on port 80 for HTTP requests.
10. Review the details and click on the “Launch” button.
11. Create or select an existing key pair to connect to your instance using SSH.
12. Click on the “Launch Instances” button.

Connect to Instance

Now that you have launched an instance, you need to connect to it using SSH. Follow these steps:

1. Find your instance in the AWS console and copy its Public IP address.
2. Open your terminal and navigate to the directory where your key pair is stored.
3. Change the permissions of your key pair by executing the following command:

$ chmod 400 my-key-pair.pem

4. Connect to your instance using SSH:

$ ssh -i my-key-pair.pem ec2-user@public-ip-address

Deploying Flask App on Server

Once you have connected to your EC2 instance, follow these steps to deploy your Flask app:

Install Dependencies

First, make sure you have all the necessary dependencies installed on your server. Install them using the following command:

$ sudo yum install python3 git

Next, clone your codebase from your Git repository:

$ git clone <your-git-repo-url>

Setup Virtual Environment

After cloning your codebase, create a virtual environment to keep the dependencies isolated:

$ python3 -m venv env

Activate the virtual environment:

$ source env/bin/activate

Install the dependencies by executing the following command:

$ pip install -r requirements.txt

Configure Flask App

Configure your Flask app by creating a configuration file and setting the necessary environment variables. Make sure you set the host to 0.0.0.0 to make it accessible from outside the server.

Run Flask App

Finally, run your Flask app using the following command:

$ export FLASK_APP=app.py$ export FLASK_ENV=production$ flask run --host=0.0.0.0

Your Flask app should now be accessible from the Public IP address of your EC2 instance.

FAQ

1. Can I use a different server provider?

Yes, you can use any server provider that suits your needs. The process of hosting a Flask app on a server is similar across all server providers.

2. Can I use a different web framework?

Yes, you can use any web framework that is supported by your server provider. The process of hosting a web framework on a server is similar across all web frameworks.

3. How do I configure my security group?

You need to allow inbound traffic on port 80 for HTTP requests to access your Flask app. You can configure your security group in the EC2 console.

4. How do I debug my Flask app on the server?

You can use the remote debugger in Flask to debug your app on the server. Set the debugger to run on port 5678 and forward the port using SSH.

5. How do I automate the deployment process?

You can use Continuous Integration and Deployment (CI/CD) tools like Jenkins, TravisCI, or CircleCI to automate the deployment process. Set up a pipeline to clone the codebase, install the dependencies, and deploy the app on the server.

Conclusion

Congratulations! You have successfully learned how to host Flask app on a server. The process may seem intimidating, but with the right knowledge and tools, it can be done easily. Hosting your Flask app on a server is an important step for making it available to the users, and we hope this article has helped you achieve that goal.