How to Build a Custom Docker Image that Runs a Python Application?| S-Logix

Description:
This task demonstrates how to create a Python script, write a Dockerfile, build a Docker image, and run it as a container that prints output from inside Docker.

Step 1: Create a Project Folder
Description: Create a new folder to store your Python code and Dockerfile.
Command:
```
mkdir python-docker-app
cd python-docker-app
            
```
Step 2: Create a Python Application
Description: Write a simple Python script that prints a message.
Action / Command:
```
nano app.py
            
```
Paste the following:
```
print("Hello from Python Docker!")
            
```
Save → CTRL + X → Y → Enter

Step 3: Create a Dockerfile
Description: Define instructions for building a Docker image that runs the Python script.
Action / Command:

nano Dockerfile

Paste the following:

FROM python:3
COPY app.py /
CMD ["python", "/app.py"]

Save and exit (CTRL + X → Y → Enter)

Dockerfile Line	Meaning
FROM python:3	Use Python base image
COPY app.py /	Copy your app into container
CMD ["python", "/app.py"]	Run the app when container starts

Step 4: Build the Docker Image
Description: Build a Docker image and give it a name.
Command:
```
docker build -t pyapp .
            
```
-t pyapp → Names the image pyapp
. → Builds using the current directory
Step 5: Run the Docker Container
Description: Execute your Python app through Docker container.
Command:
```
docker run pyapp
            
```
Expected Output:
```
Hello from Python Docker!
            
```

List

S-Logix (OPC) Private Limited