The ultimate guide to Ruby concurrency interviews. Developed by FAANG engineers, this course covers Monitors, Deferred Callbacks and problem-solving strategies for Reader-Writer and Dining Philosopher Problems.

Concurrency in Ruby is one of the most complex and advanced topics brought up during senior engineering interviews. Knowledge of concurrency and multithreading can put interviewees at a considerable advantage. This course lays the foundations of advanced concurrency and multithreading and explains concepts such as Monitors and Deferred Callbacks in depth. It also builds simple and complete solutions to popular concurrency problems that can be asked about in interviews like the Reader-Writer Problem and the Dining Philosopher Problem. While prior knowledge of concurrency is not required to follow through with this course, familiarity with the basics of Ruby would be helpful.

Ruby Concurrency for Senior Engineering Interviews

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   # Mutex   
   <div class="ans">
<p><code class="clazz">Mutex</code> is the most basic or primitive synchronization construct available in Ruby. It offers two methods: <code class="mthd">lock()</code> and <code class="mthd">unlock()</code>. <span class="hi-yl">A   <code class="clazz">Mutex</code> object can only be unlocked by a thread that locked it in the first place.</span> Consider the snippet below, where the child and the main thread alternatively acquire the mutex. The main thread blocks for the period the child holds the mutex.</p>
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require 'date'

# Create a Mutex object
mutex = Mutex.new

# Spawn a child thread
Thread.new do
  puts("Child thread acquiring mutex")
  mutex.lock()
  sleep(3)
  puts("Child thread releasing mutex")
  mutex.unlock()
end

# Sleep main thread to give child thread a
# chance to acquire the mutex first
sleep(1)
puts("Main thread attempting to acquire mutex")
mutex.lock()
puts("Main thread acquires mutex")
mutex.unlock()

<div class="ans">

<p>As mentioned in the previous introductory sections, a mutex has a notion of ownership. The <code class="clazz">Thread</code> class has an instance method <code class="mthd">owned?()</code> which can be used to know if the current thread has locked the mutex. Consider the code widget below; the main thread becomes an owner after it locks the mutex.</p>

</div>

<div>
   # Mutex   
   <div>
<p><code>Mutex</code> is the most basic or primitive synchronization construct available in Ruby. It offers two methods: <code>lock()</code> and <code>unlock()</code>. <span>A   <code>Mutex</code> object can only be unlocked by a thread that locked it in the first place.</span> Consider the snippet below, where the child and the main thread alternatively acquire the mutex. The main thread blocks for the period the child holds the mutex.</p>
</div>
</div>

<div>

<p>As mentioned in the previous introductory sections, a mutex has a notion of ownership. The <code>Thread</code> class has an instance method <code>owned?()</code> which can be used to know if the current thread has locked the mutex. Consider the code widget below; the main thread becomes an owner after it locks the mutex.</p>

</div>

This lesson discusses Mutex as used in Ruby.

The Basics

API Overview

Brief Intro to Asynchronous Programming

Interview Practice Problems

Bonus Questions

Epilogue

Mutex

Mutex