Deploying a Python application using Docker involves several steps. The following guide assumes that you have Docker installed on your system.
For this example, let’s imagine you have a simple Flask application you want to deploy:
1. Create a Dockerfile in your project directory. A Dockerfile is a script containing commands that assemble an image. It might look like this:
```
FROM python:3.7
WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt
COPY . .
CMD [“python”, “app.py”]
```
1. Explanation of the Dockerfile:
- `FROM python:3.7`: This line is telling Docker to base our image off of the standard Python 3.7 image.
- `WORKDIR /app`: Change the working directory in Docker to /app.
- `COPY requirements.txt .`: This line is copying our `requirements.txt` file into the Docker image.
- `RUN pip install -r requirements.txt`: Run pip install command in the Docker environment to install dependencies.
- `COPY . .`: The application’s code is copied into the image.
- `CMD [“python”, “app.py”]`: The final line is the command that runs our application.
1. In the directory with the Dockerfile and your application, build the Docker image (don’t forget the period at the end):
```
docker build -t your-image-name .
```
In this command, `-t your-image-name` is giving your image a tag or a name.
1. Now, you can run your application inside a Docker container. Run this command:
```
docker run -d -p 5000:5000 your-image-name
```
The `-d` flag is used to run the container in the background. `-p 5000:5000` is telling Docker to map port 5000 inside Docker as port 5000 on your machine.
Now, your Python application is running inside a Docker container.
Remember, this is a very basic example. Depending on the complexity of your application, you may need to add database services, environment variables, volumes, etc to your Dockerfile or Docker Compose file.
