Thread safety concepts in Ruby - Mini Project: Build & Apply

Thread Safety Concepts in Ruby

📖 Scenario: Imagine you are building a simple bank system where multiple people can deposit money into the same account at the same time. To keep the account balance correct, you need to make sure that the updates to the balance are done safely when many threads work together.

🎯 Goal: You will create a Ruby program that shows how to safely update a shared bank account balance using thread safety concepts.

📋 What You'll Learn

Create a shared bank account balance variable

Create a mutex lock to control access to the balance

Use multiple threads to deposit money safely

Print the final balance after all deposits

💡 Why This Matters

🌍 Real World

Thread safety is important in real-world programs where many tasks run at the same time and share data, like banking apps or online stores.

💼 Career

Understanding thread safety helps you write reliable and bug-free code in jobs that involve concurrent programming or server-side development.

1

Create the shared bank account balance

Create a variable called balance and set it to 0 to represent the starting bank account balance.

Ruby

# Create a variable called balance and set it to 0
# Your code here

Need a hint?

Use a simple variable assignment like balance = 0.

2

Create a mutex lock for thread safety

Create a variable called mutex and set it to a new Mutex object to control access to the shared balance.

Ruby

require 'thread'
balance = 0
# Create a mutex lock called mutex
# Your code here

Need a hint?

Use Mutex.new to create a new lock.

3

Use threads to deposit money safely

Create 5 threads that each add 100 to balance safely using mutex.synchronize to lock the update. Use a variable called threads to store the thread objects.

Ruby

require 'thread'
balance = 0
mutex = Mutex.new
# Create 5 threads to add 100 to balance safely
# Your code here

Need a hint?

Use 5.times do to create threads, and inside each thread use mutex.synchronize to safely update balance.

4

Print the final balance

Write a puts statement to print the final value of balance after all threads have finished.

Ruby

require 'thread'
balance = 0
mutex = Mutex.new
threads = []
5.times do
  threads << Thread.new do
    mutex.synchronize do
      balance += 100
    end
  end
end
threads.each(&:join)
# Print the final balance
# Your code here

Need a hint?

Use puts balance to show the final amount.