adding a sample for using fiber

Author: taf2

samples/fiber_crawler.rb

@@ -0,0 +1,90 @@
+#!/usr/bin/env ruby
+
+# Use the locally built curb (extension + libs) instead of any installed gem.
+$LOAD_PATH.unshift File.expand_path('../lib', __dir__)
+$LOAD_PATH.unshift File.expand_path('../ext', __dir__)
+
+require 'curl'
+
+# Demo parameters
+GROUPS = (ENV['GROUPS'] || 3).to_i
+PER_GROUP = (ENV['PER_GROUP'] || 5).to_i
+CONNECT_TIMEOUT = (ENV['CONNECT_TIMEOUT'] || 5).to_i
+TOTAL_TIMEOUT   = (ENV['TOTAL_TIMEOUT'] || 15).to_i
+DELAY_S   = (ENV['DELAY_S'] || 0.25).to_f
+
+require 'webrick'
+require 'async'
+
+# Start a small local HTTP server on loopback and wait until it’s listening.
+ready = Queue.new
+server = WEBrick::HTTPServer.new(
+  BindAddress: '127.0.0.1',
+  Port: (ENV['PORT'] || 0).to_i,    # 0 chooses a free port
+  Logger: WEBrick::Log.new($stderr, WEBrick::Log::FATAL),
+  AccessLog: [],
+  StartCallback: -> { ready << true }
+)
+server.mount_proc('/test') do |_req, res|
+  sleep DELAY_S
+  res.status = 200
+  res['Content-Type'] = 'text/plain'
+  res.body = 'OK'
+end
+
+server_thread = Thread.new { server.start }
+ready.pop # wait until the server is bound
+bound_port = server.listeners.first.addr[1]
+URL = "http://127.0.0.1:#{bound_port}/test"
+
+puts "Async demo: groups=#{GROUPS} per_group=#{PER_GROUP} url=#{URL} delay=#{DELAY_S}s"
+
+def crawl(url)
+  c = Curl::Easy.new
+  c.url = url
+  c.connect_timeout = CONNECT_TIMEOUT
+  c.timeout = TOTAL_TIMEOUT
+  start = Time.now
+  code = nil
+  error = nil
+  begin
+    c.perform
+    code = c.response_code
+  rescue => e
+    code = -1
+    error = "#{e.class}: #{e.message}"
+  end
+  { code: code, error: error, duration: (Time.now - start) }
+end
+
+results = []
+started = Time.now
+if Async.respond_to?(:run)
+  Async.run do |top|
+    GROUPS.times do
+      PER_GROUP.times do
+        top.async do
+          results << crawl(URL)
+        end
+      end
+    end
+  end
+else
+  Async do |top|
+    GROUPS.times do
+      PER_GROUP.times do
+        top.async do
+          results << crawl(URL)
+        end
+      end
+    end
+  end
+end
+duration = Time.now - started
+
+ok = results.count { |r| r[:code] == 200 }
+fail = results.count { |r| r[:code] != 200 }
+puts "Completed #{results.size} requests in #{duration.round(3)}s (ok=#{ok}, fail=#{fail})"
+
+server.shutdown
+server_thread.join