Token bucket algorithm in Rest API - Mini Project: Build & Apply

Token Bucket Algorithm Implementation

📖 Scenario: You are building a simple rate limiter for an API using the token bucket algorithm. This algorithm controls how many requests a user can make in a given time by using tokens that refill over time.

🎯 Goal: Create a Python program that simulates a token bucket rate limiter. You will set up the initial bucket, configure the refill rate, implement the token consumption logic, and finally print whether a request is allowed or denied based on available tokens.

📋 What You'll Learn

Create a dictionary called token_bucket with keys 'capacity' and 'tokens' set to 10 and 10 respectively.

Create a variable called refill_rate and set it to 2 (tokens per second).

Write a function called consume_tokens that takes tokens_needed and reduces tokens if enough are available, returning True if allowed, False otherwise.

Print the result of calling consume_tokens(5).

💡 Why This Matters

🌍 Real World

Token bucket algorithms are used in APIs and networks to limit how many requests or data packets can be processed in a given time, preventing overload.

💼 Career

Understanding rate limiting is important for backend developers and network engineers to build reliable and fair services.

1

Set up the token bucket dictionary

Create a dictionary called token_bucket with keys 'capacity' and 'tokens' both set to 10.

Rest API

# Create the token_bucket dictionary with 'capacity' and 'tokens' set to 10
# Your code here

Need a hint?

Use curly braces to create a dictionary with the exact keys and values.

2

Add the refill rate variable

Create a variable called refill_rate and set it to 2.

Rest API

token_bucket = {'capacity': 10, 'tokens': 10}
# Create the refill_rate variable and set it to 2
# Your code here

Need a hint?

Just assign the number 2 to the variable named refill_rate.

3

Write the token consumption function

Write a function called consume_tokens that takes a parameter tokens_needed. Inside, check if token_bucket['tokens'] is at least tokens_needed. If yes, subtract tokens_needed from token_bucket['tokens'] and return True. Otherwise, return False.

Rest API

token_bucket = {'capacity': 10, 'tokens': 10}
refill_rate = 2
# Define the consume_tokens function below
# Your code here

Need a hint?

Use an if-else statement to check tokens and update the dictionary.

4

Print the result of token consumption

Print the result of calling consume_tokens(5).

Rest API

token_bucket = {'capacity': 10, 'tokens': 10}
refill_rate = 2

def consume_tokens(tokens_needed):
    if token_bucket['tokens'] >= tokens_needed:
        token_bucket['tokens'] -= tokens_needed
        return True
    else:
        return False

# Print the result of consume_tokens(5) below
# Your code here

Need a hint?

Use the print function to show the result of consume_tokens(5).