Write-through pattern in Redis - Mini Project: Build & Apply

Implementing Write-Through Pattern with Redis

📖 Scenario: You are building a simple caching system for a product catalog using Redis. The goal is to keep the cache and the database synchronized so that when a product's price is updated, both the cache and the database reflect the change immediately.

🎯 Goal: Build a write-through cache pattern where updates to product prices are written to both Redis cache and the database at the same time.

📋 What You'll Learn

Create a Redis hash to store product prices with exact keys and values

Define a variable for the database simulation with the same product data

Write a function to update the product price in both Redis and the database

Ensure the final code updates both data stores correctly

💡 Why This Matters

🌍 Real World

Write-through caching is used in web applications to keep cache and database synchronized, improving performance and data consistency.

💼 Career

Understanding write-through patterns is important for backend developers and database administrators working with caching systems and data synchronization.

1

Create Redis hash with product prices

Create a Redis hash called product_prices with these exact entries: product1: 100, product2: 200, product3: 300.

Redis

# Your code here to create Redis hash 'product_prices' with given entries

Need a hint?

Use the HMSET command to create a hash with multiple fields and values.

2

Simulate database with a dictionary

Create a variable called database as a dictionary with these exact entries: 'product1': 100, 'product2': 200, 'product3': 300.

Redis

HMSET product_prices product1 100 product2 200 product3 300
# Your code here to create 'database' dictionary with given entries

Need a hint?

Use Python dictionary syntax to create the database variable.

3

Write update function for write-through

Write a function called update_price that takes product and new_price as parameters and updates the price in both the Redis hash product_prices and the database dictionary.

Redis

HMSET product_prices product1 100 product2 200 product3 300
database = {'product1': 100, 'product2': 200, 'product3': 300}

def update_price(product, new_price):
    # Your code here to update Redis and database

Need a hint?

Use the HSET command to update Redis and assign the new price in the dictionary.

4

Complete write-through update with Redis command execution

Add a line inside update_price to execute the Redis command string stored in redis_command using a Redis client method called execute_command.

Redis

HMSET product_prices product1 100 product2 200 product3 300
database = {'product1': 100, 'product2': 200, 'product3': 300}

def update_price(product, new_price):
    redis_command = f"HSET product_prices {product} {new_price}"
    # Your code here to execute redis_command
    database[product] = new_price

Need a hint?

Call redis_client.execute_command(redis_command) to send the update to Redis.