Use thread pooling to prevent large number of threads

Gemfile

@@ -2,6 +2,7 @@ source 'https://rubygems.org'
 
 ruby "3.2.2"
 
+gem 'concurrent-ruby'
 gem 'pry'
 
 group :test do

Gemfile.lock

@@ -4,6 +4,7 @@ GEM
     addressable (2.8.4)
       public_suffix (>= 2.0.2, < 6.0)
     coderay (1.1.3)
+    concurrent-ruby (1.2.2)
     crack (0.4.5)
       rexml
     diff-lcs (1.5.0)
@@ -36,6 +37,7 @@ PLATFORMS
   arm64-darwin-20
 
 DEPENDENCIES
+  concurrent-ruby
   pry
   rspec
   webmock

lib/image_downloader.rb

@@ -1,12 +1,15 @@
 require 'open-uri'
 require 'net/http'
+require 'concurrent'
 
 class ImageDownloader
   def self.download_images(urls, target_dir = "./images")
     Dir.mkdir(target_dir) unless File.exist?(target_dir)
 
-    threads = urls.map do |url|
-      Thread.new do
+    pool = Concurrent::FixedThreadPool.new(10)
+
+    urls.each do |url|
+      pool.post do
         begin
           uri = URI.parse(url)
           http = Net::HTTP.new(uri.host, uri.port)
@@ -28,6 +31,7 @@ def self.download_images(urls, target_dir = "./images")
       end
     end
 
-    threads.each(&:join) # Wait for all threads to finish
+    pool.shutdown
+    pool.wait_for_termination
   end
 end