Project Introduction: Connect Python with Redis Using Docker Compose

This project demonstrates how to connect a Python application with a Redis database using Docker Compose, a powerful tool for running multi-container Docker applications. Redis is a popular in-memory key-value store, often used for caching, real-time analytics, or session management. In this setup:

The Python app acts as a client that sends data to and retrieves data from Redis.
Redis runs in a separate container.
Both containers are orchestrated using a single docker-compose.yml file.
No manual networking setup is needed—Docker Compose takes care of connecting both services automatically.

This is a great beginner-friendly example to understand container linking, service communication, and micro-service deployment using Docker.

Connecting Python to Redis

Importing Dependencies:

import redis import time

redis: This is the Redis client library for Python, which lets you connect to a Redis server and perform operations like get, set, etc.
time: This is used to introduce a delay, ensuring the Redis service is up before the Python script attempts a connection.

2. Delay to Allow Redis to Start:

time.sleep(3)

This 3-second sleep gives the Redis container enough time to start up before the Python script tries to connect to it.
It's crucial when both services are started simultaneously using Docker Compose.

3. Connect to Redis Container:

r = redis.Redis(host='redis', port=6379)

This line connects the Python app to the Redis server.
host=’redis’ : This is not an IP—it’s the name of the Redis service defined in your docker-compose.yml. Docker Compose sets up DNS for service discovery.
port=6379: The default port on which Redis listens.

4. Store and Ret0rieve Data:

r.set('name', 'Yash')

data value = r.get('name')

Sets a key-value pair in Redis where name is the key and 'Yash‘ is the value.
Immediately fetches that same key from Redis.

5. Display the Value:

print("Stored value from Redis:", value.decode())

Redis returns bytes, so decode() is used to convert it to a human-readable string.
This prints:
Stored value from Redis: Yash

Dockerfile

FROM python: 3.10-alpine

Uses the official lightweight Python 3.10 image (Alpine-based) as the base for the container.
Alpine is great for small, fast images.

WORKDIR /app

Sets the working directory inside the container to /app.
All subsequent commands will run from this directory.

COPY main.py .

Copies the main.py file from your local project directory into the container’s /app directory.

RUN pip install redis

Installs the redis Python package, which allows Python code to communicate with a Redis server.

CMD ["python", "main.py"]

Specifies the command that will run when the container starts.
It runs your script using Python.

version: ‘3’

Specifies the version of Docker Compose syntax being used (v3 is compatible with modern Docker engines).

services

This section defines all the containers (services) that will be launched.

redis

image: redis-alpine
Pulls the official lightweight Redis image based on Alpine Linux.
container_name: redis_server
Names the container for easier reference and logs.

app

build: ./app
Builds the Python container using the Dockerfile located in the app directory.
container_name: python_client
Gives the Python container a custom name.
depends_on: - redis
Ensures the Redis service starts before the Python app, helping prevent connection errors during startup.

What’s happening?

redis_server

This service starts the Redis container.
You can see it loading modules like:
- search, timseries, and ReJSON
It registers its internal configurations and finally logs:

Ready to accept connections tcp

This means the Redis server is up and running.

python_client

The Python container connects to the Redis server, stores the key-value pair name:Yash, and retrieves it.

It prints:

Stored value from Redis: Yash
Then, the container exits cleanly with:

exited with code 0

This indicates successful execution without errors.

Connected Python with Redis Using Docker Compose