books

README

books

This set of exercises involves creating a "pipeline", a concept that requires channels and goroutines.

Exercise 1a: A Simple Pipeline

For this exercise, you will create a simple Go pipeline.

(The concept of pipelines in Go is explained in this classic Go blog post on the subject. The main points of that article are still valid, though some of the specifics may be a little dated. The part of the article up to the "Stopping short" section are the most relevant.)

Take a look at the file simple\squares.go. This file contains a function that generates a random number, as well as a function that takes a number and squares it. Each function is bit slow at doing its work.

The function NoPipleline() uses both these functions to generate 50 squares and print them out. It also prints the time elapsed. (It runs when you do go run main.go)

Create a new function, Pipeline(), that uses the pipeline pattern to generate and print 50 squares concurrently.

Hint: Your pipeline will run three functions that you write, perhaps named:

• GenerateNumbers
• SquareNumbers
• PrintNumbers

Exercise 1b: Multiple Concurrent Workers

For this exercise, take your solution from Exercise 1a and make it run faster by running multiple instances (5 might be a good number) of SquareNumbers at the same time.

Exercise 2a: Overlapping Words

Given the name of an author, write a program that prints out a list of all the words that appear in all of their books (of four letters or more). Use a pipleline in order to allow for concurrent processing.

---

For example, author SANDY has written three books:

"Baseball Is Fun"

This is a book about baseball. It is a story of a time I found myself looking
 for answers, and discovered them in a little, sewn ball.

"A Day to Remember"

The first time I rode on the bus, I had a ball. There was even an exciting
 moment when a baseball player came on the bus.

"Best Sports"

Baseball is a sport, but soccer (also known as football) is so much better. I
 have been a soccer player for as long as I can remember. One thing in common
 between these two sports is that they each rely on a ball.

If we supply our program with the name "SANDY" we will get back: baseball , ball

---

To solve this problem, you have been given two services, shown here:

• booklist.Service
  • .GetByAuthor(authorName string) []*Book
• bookdetails.Service
  • .Get(filename string) (io.ReadCloser, error)

Their usage is shown in the function tryBookFunctions() in main.go. Running go run main.go will cause this function to be executed. NOTE: You must update dataDirectory to your directory in order for this to work.

Exercise 2b: Cancellation

In this exercise we will add the ability to cancel an in-progress pipeline.

Gracefully shut down your program when you receive cancellation from the operating system (Ctrl-C). Do this by adding a context.Context to each function in the pipeline from Exercise 2a and paying attention to it getting canceled.