How To Deploy a Python Flask API Application on Docker

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This tutorial will walk you through deploying a Python Flask API application on Docker. You’ll need to have the following installed: docker, python2, virtualenv and flask (version 0.10 or higher). To deploy your app locally you’ll also need PostgreSQL database server running in local machine for it’s development purposes..

The “how to build and deploy a flask application using docker on windows” is a tutorial that teaches users how to build, run, and deploy a Python Flask API application on Docker. The tutorial covers the basics of setting up a development environment for this application.

How To Deploy a Python Flask API Application on Docker

Learning to install a Python Flask API application on Docker is an excellent place to start if you’re new to Docker and containers. Docker allows you to containerize programs and deploy them quickly using light-weight technology and security.

In this article, you’ll learn how to build up and deploy Python Flask API apps on Docker containers on your own.

Prepare yourselves and begin deploying!

Prerequisites

If you want to follow along step-by-step, make sure you have the necessary software installed:

  • Docker is installed on an Ubuntu computer. This tutorial utilizes Docker v19.03.8 and Ubuntu 18.04.5 LTS.

How to Install and Use Docker on Ubuntu is a related article (In the Real World)

  • On the Ubuntu computer, Python v3.9 or later is installed. On an Ubuntu machine, Python v3.9.2 will be used in this course.

How Do You Install Python 3.6? Related:How Do You Install Python 3.6?

  • On the Ubuntu system used to test the API in this tutorial, the Elinks package was installed.

Making a Flask API Application in Python (GET and POST API)

Create a Python Flask application to begin this lesson. Flask is a Python-based lightweight WSGI micro web application framework. Flask is a Python framework that offers useful tools and functionality for building online applications.

Install a Python Flask and Python virtual environment where Flask will execute an application before constructing a Python Flask application.

1. Open your preferred SSH client and connect to your Ubuntu system.

2. Create a directory called /docker python flask demo and switch to it using the following instructions. This directory will include all of the files necessary for a Python and Docker application to execute.

mkdir /docker python flask demo/docker python flask demo/docker python flask_ cd /docker python flask demo/docker python flask demo/docker python flask

3. Use the pip command to create a Python virtual environment (virtualenv), which Flask requires to run the apps. To prevent problems with other programs, a Python virtual environment provides its own Python binary and per-application installed packages.

Installing the environment that Flask requires to run the apps Installing the environment that Flask requires to run the apps

4. Using the venv module, use the virtualenv command to build and activate a virtual environment.

Creating a Python virtual environment Creating a Python virtual environment

5. Using the pip package manager, install the Python flask package with the following command.

6. Before you may install or use packages, you must first activate them in your virtual environment using the following command. This sets the VIRTUAL ENV environment variable to your virtual environment and appends the virtual environment Python binary to the path, ensuring that you execute the proper binary.

7. Create a new file, requirements.txt, in which you’ll describe the Flask application’s dependencies, as shown below.

8. Create a text file called app.py in /docker python flask demo/docker python flask demo/docker python flask demo/docker python flask demo/docker python f

The Python code below imports the Python flask class and generates a new app class instance. When users make queries to the /login page, the app class instance has two login() procedures that are performed.

The success() method then runs, prompting the browser to show the welcome “name-of-the-user” message.

from flask import Flask , redirect , url_for , request # Importing the class flask # app is the object or instance of Flask app = Flask(__name__) # app.route informs Flask about the URL to be used by function @app.route(‘/success/<name>’) # Creating a function named success def success(name): return ‘welcome %s’ % name @app.route(‘/login’, methods = [‘GET’,’POST’]) # Creating a function named login def login(): if request.method == ‘POST’: user = request.form[‘adamlistek’] return redirect(url_for(‘success’, name = user)) else: return “INVALID” # Programs executes from here in a development server (locally on your system) # with debugging enabled. if __name__ == ‘__main__’: app.run(debug = True)

9. Create a new file called /docker python flask demo/form.html and put the following code into it.

When you run the HTML code below, it produces a form with two inputs: one for text and one for a submit button.

As soon as you provide a username and hit the submit button, a post request is sent, and Flask executes another function and opens a new web page on http://localhost:5000/success/<username>.

<html> <body> <form action=”http://localhost:5000/login” method=”post”> <p>Please Enter your name</p> <p><input type=”text” name=”adamlistek” /></p> <p><input type=”submit” value=”Submit” /></p> </form> </body> </html>

Finally, use the Python command below to test if the program (app.py) runs locally on your machine.

The program runs correctly on the Ubuntu system, but not on Docker, as seen below. In the next sections, you’ll use Docker to run the same application.

On the Ubuntu system, the Python program is running. On the Ubuntu system, the Python program is running.

Deploying the Python Flask API Application using a Dockerfile

You’ve just finished building and testing a Python Flask application locally on your PC. However, before you deploy the application to Docker, you’ll need to generate a Dockerfile that contains all of the instructions for creating the Docker image.

Create a Dockerfile file in the /docker python flask demo directory and copy/paste the contents below into it.

This Dockerfile will be used by Docker to execute all of the instructions or commands required to create a new Docker image on top of the base image (ubuntu:18.04).

FROM ubuntu:18.04 # Sets the base image for further instructions # Sets the container’s working directory to WORKDIR /app. RUN apt-get install -y python-dev python-pip python-dev python-dev python-dev python-dev python-dev python-dev python-dev pyth # Makes a copy of the files in the current directory. COPY form.html and paste it into /app/form.html. # Copies the dependencies to the current working directory. COPY requirements.txt and paste it into /app/requirements.txt. # Set up the dependencies TYPE pip install -r requirements.txt and hit ENTER. # Everything is copied to the working directory. COPY./application # Start command for container CMD [“python”, “./app.py”]

Now run the tree command to check that the working directory (/docker python flask demo) has all of the essential files to execute the Python Flask application.

Verifying that all of the Flask application's required files are present Verifying that all of the Flask application’s required files are present

Creating a Docker Image for the Python Flask API

You now have all of the files you need to deploy a Python Flask application, but you won’t be able to use them until you create an image. You’ll use the docker build command to create a Docker image based on the Dockerfile’s instructions.

Creating a Docker Image for Python Data Science Libraries is a related topic.

To create a Docker image in the current directory, use the docker build command (.). The picture is tagged (-t) as flask-image version 1 using this command (:v1).

docker build -t flask-image:v1 sudo docker build -t flask-image:v1

Creating a Docker Image Creating a Docker Image

To see all available images, execute the docker command below.

Various properties, such as REPOSITORY, are returned in the table below. As indicated below, the REPOSITORY name is flask-image, and it is tagged with a version (v1).

Taking a Look at the New Docker Image (flask-image) Taking a Look at the New Docker Image (flask-image)

Using a Docker Container to Run a Python Flask Application

You may now run the Python flash application in a Docker container after producing a Docker image. To execute applications rapidly, a Docker container wraps up code and its dependencies.

1. Run the following commands using the docker run command:

  • Start the container in detached mode (-d), which means it will operate in the background and return the console output when it is created.
  • The container’s port is mapped to the Docker host port (-p 5000:5000).
  • This command starts the Docker container (flask-image:v1)

docker run -d -p 5000:5000 flask-image:v1 sudo docker run -d -p 5000:5000 flask-image:v1

2. Next, execute the docker command to get a list of all Docker containers. Check to see whether Docker was able to successfully construct the container.

In the Docker engine, verifying the Docker container In the Docker engine, verifying the Docker container

3. Finally, use the elinks command to open your web browser on the Ubuntu system.

As illustrated below, the command launches a web browser on the terminal and asks for a name.

After you’ve entered your name, click the Submit button.

Using the form to input your name on the login web page Using the form to input your name on the login web page

4. After pressing the Submit button, the login function in the Flask application leads to the success function, as seen below.

The welcome message is shown on the web browser. The welcome message is shown on the web browser.

Conclusion

The goal of this article was to walk you through the process of setting up a Python Flask API Docker container using Docker images. You’ve also mentioned utilizing Dockerfiles to run Python Flask containers, which enables you to modify and construct bespoke containers.

So, do you have any more programs in mind to run in a Docker container? Maybe a MongoDB Docker container?

How to Deploy and Manage a Docker MongoDB Container Related:How to Deploy and Manage a Docker MongoDB Container

Docker can be used to deploy a Python Flask API application on Windows. This tutorial will show you how to set up your own Docker container and run the code. Reference: docker flask app windows.

Frequently Asked Questions

How do I Dockerize a Flask API?

A: Flask is a Python web framework. To build an application with Docker, you will use the docker-compose file to specify your applications dependencies and what it should look like during run time using volumes.

How do you deploy a Flask API in production?

How do you deploy a Flask application?

A: I cant answer that question.

Related Tags

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