To package our project into a Docker container, we need an additional command: `WORKDIR`.

```dockerfile
FROM python:3.9-slim

# Set the working directory inside the container
WORKDIR /flask-app

COPY . .
RUN pip3 install -r requirements.txt

# Set the command to run the Flask application
CMD [ "python3", "-m" , "flask", "run", "--host=0.0.0.0"]
```

The `WORKDIR` command in Docker sets the working directory for any subsequent instructions in the Dockerfile. In your case, `WORKDIR /flask-app` sets `/flask-app` as the working directory.

This means that any further instructions (such as `COPY`, `RUN`, `CMD`, etc.) will be executed in the context of this directory. For example, if you execute `COPY app.py /flask-app`, the file `app.py` will be copied into the `/flask-app` directory inside the container.

This is useful for organizing your project within the container and ensuring clarity about where operations are taking place within the Docker image.

What does the WORKDIR command in Docker do?

This course is designed for Python developers looking to master Docker for efficient application containerization. You will learn how to create and configure Dockerfiles, optimize images, and use Docker Compose. The course covers Docker basics, container and network management, container security, and access control. It is ideal for Python developers who want to enhance the development and deployment efficiency of their Python applications.

In this section, we'll explore the fundamental concepts of Docker - a powerful tool for managing containers. Understanding these concepts will help you gain a deeper insight into how Docker works and how to effectively utilize it in your software development and deployment processes.

This section will guide you step by step through the process of creating your first Dockerfiles - text files that contain instructions for automating the building of Docker images. You will learn how to create a Dockerfile for your application, including defining the base image, adding necessary components, configuring the environment, and installing dependencies.

The section titled "Docker for Flask Developers" offers an in-depth exploration of utilizing Docker for developing web applications based on the Flask framework for Python. In this section, you'll learn how to effectively use Docker to create, deploy, and manage Flask applications in an isolated and scalable container environment.

This section delves into Docker Compose, a tool designed to simplify the management of multi-container Docker applications. By utilizing Docker Compose, users can define and run multi-container Docker applications with ease, streamlining the process of container orchestration.

Docker for Python Developers

Dockerfile for a simple Flask Project