Rack-AMQP: Ditch HTTP inside SOA!

We’re comfortable with HTTP, but using it for communication in your SOA isn’t simple. You need load balancers, URL discovery, SSL, and there’s a cost to set up and tear down that HTTP window.

Rack-AMQP lets you serve your rack (and rails) apps over AMQP, a robust, open protocol for messaging. You get simple queues, load balancing, security, and persistent connections for free (plus pub-sub!)—without changing your app.

Learn the pitfalls of HTTP and why you should use AMQP in your SOA!

A video is available at https://www.youtube.com/watch?v=cINCWpn-LQM

Transcript

1. RACK-AMQP Ditch HTTP Inside Your SOA! @jszmajda
2. RACK-AMQP IS Jackalope AMQP-HTTP RFC Rack-AMQP-client AMQParty amqurl rails-demo Image Credit http://www.deviantart.com/art/Jackalope-76202872
3. A new ruby web application server Like Passenger, Unicorn, Puma, or Thin Special Purpose - SOA No HTTP JACKALOPE Image Credit http://fliegertruppen.deviantart.com/art/Jackalope-For-Luck-146298053
4. WHY
5. My App
6. MY APP IS COMPLEX 350 models Demeter violations 8 hour test suite Scale Background jobs
7. SOA
8. SOA? Enterprise Service Bus Interface Definition Language Rigid Contracts Versions
9. SOA IS COMPLEX More apps Load Balancing Configuration Monitoring Tracking and Clarity
11. –Wikipedia “Service-oriented architecture (SOA) is a software design and software architecture design pattern based on discrete pieces of software providing application functionality as services to other applications”
12. SOA Enforces Simplification SOA Mitigates Complexity
13. Independent actors communicating WHAT IS SOA, REALLY?
14. COMMUNICATION Messages between actors Requests, responses Notifications Broadcasts Subscriptions
15. WHAT WE KNOW We write Web Apps We're comfortable with HTTP HTTP is powerful
16. TRANSPORT Data Structure Independent (blind pipe) Fast Open, clear Debuggable and Traceable Observable Flexible
17. WHAT WE NEED RPC (request/response) Publish / Subscribe Broadcast messaging
18. WHAT WE DON'T NEED More Load balancers More SSL certificates Distributed management Service discovery
19. HTTP Blind pipe Fast Open Distributed Great for RPC Image Credit Chua Hock Chuan http://www3.ntu.edu.sg/home/ehchua/programming/webprogramming/http_basics.html
20. AMQP Blind pipe Fast Open Great for all messaging needs Centralized Not what we know!
21. RACK-AMQP Jackalope: A new server for Rack-based applications Transparently serves Rack (HTTP) applications over AMQP As few opinions as necessary Allows for Pub/Sub and other messaging patterns Queues everywhere - No Load Balancers Fewer Components
22. BUILDING WHAT WE KNOW We are web developers, we understand web development Jackalope is just another rack application server We can still build and debug what we know We deploy with Jackalope and it just works
23. HOW
24. AMQP Advanced Message Queuing Protocol Open Standard Developed by OASIS Centralized distribution pattern
25. AMQP DISTRIBUTION Centralized Distribution allows for RPC as well as more complex messaging patterns
26. AMQP MESSAGES Headers and Bodies Well-known fields routing key persistent mandatory content type content encoding priority Content Length Content Type Content Encoding Body Headers Status
27. CONVENTIONS HTTP has a straightforward structure that's easy to emulate AMQP has conventions that map easily to HTTP concepts AMQP supports RPC messaging pattern
28. AMQP-HTTP SPEC RPC message pattern Co-opting standard AMQP concepts
29. HTTP MESSAGES Image Credit Chua Hock Chuan http://www3.ntu.edu.sg/home/ehchua/programming/webprogramming/http_basics.html
30. Request Response Image Credit Chua Hock Chuan http://www3.ntu.edu.sg/home/ehchua/programming/webprogramming/http_basics.html
31. AMQP-HTTP HTTP AMQP Protocol n/a Hostname Routing Key Port n/a Headers Headers URI Headers[‘path’] Request Method Type Content Length Headers[‘Content-Length’] Content Type Content Type Content Encoding Content Encoding Body Body Headers Headers Status X-AMQP-HTTP-Status
32. AMQP-HTTP 1 def request(hostname, uri, params)! 2 callback_queue = create_response_queue! 3 amqp.publish('', {! 4 type: 'GET',! 5 headers: { path: ‘/doc/test.html’ },! 6 app_id: ‘Mozilla/4.0’,! 7 routing_key: ‘my.awesome.service',! 8 reply_to: callback_queue.name,! 9 timestamp: Time.now.to_i,! 10 message_id: request_id,! 11 })! 12 wait_for_response(callback_queue)! 13 end
33. RACK API All ruby web applications run on Rack (Rails, Sinatra, etc) Doesn't actually care about HTTP 1 require 'rubygems'! 2 require 'rack'! 3 ! 4 class HelloWorld! 5 def call(env)! 6 [200, {"Content-Type" => "text/html"}, "Hello Rack!"]! 7 end! 8 end
34. HTTP EMULATION 1 def server! 2 amqp.subscribe(queue) do |meta, body|! 3 ... unpack stuff ...! 4 env.update({! 5 'REQUEST_METHOD' => http_method,! 6 'PATH_INFO' => uri,! 7 'QUERY_STRING' => query,! 8 'REQUEST_PATH' => uri,! 9 "rack.input" => StringIO.new(body)! 10 })! 11 response_code, headers, body = app.call(env)! 12 publish_response(response_code, headers, body)! 13 end! 14 end! 15
35. JACKALOPE Emulates a HTTP environment for your Rack app It Just Works
37. RABBITMQ Open-source AMQP broker Easy to use All major operating systems Secure Distributed, Fault-Tolerant, Highly Available
38. RABBITMQ MANAGEMENT
39. ARCHITECTURE Service Service Service Service Service Rabbit API API APIs Service Service Service Service Service Service Service
40. CODE - CLIENT AMQParty - API-compatible with HTTParty 1 require 'amqparty'! 2 AMQParty.get('amqp://users.service/users.json') 1 def get(uri, options={})! 2 transport.get(target(uri), options)! 3 end HTTParty or AMQParty
41. CODE - CLIENT 1 require 'rack/amqp/client'! 2 client = Rack::AMQP::Client.client({host: 'rabbitmqhost'})! 3 response = client.request("some.queue/users.json", {! 4 body: "",! 5 http_method: "GET",! 6 headers: {},! 7 timeout: 5! 8 })! 9 puts "Response Code: #{response.response_code}"! 10 puts "Headers:"! 11 response.headers.each_pair do |key, value|! 12 puts " #{key}: #{value}"! 13 end! 14 puts "Body:\n\n#{response.body}"
42. SAMPLE SOA WITH RAILS interface - “API” service userland - users service userland_client - client to userland
43. (MICRO)BENCHMARKS 3 AMQParty.configure { |c| c.amqp_host = 'localhost' }! 4 ! 5 RUNS = 500! 6 Benchmark.bm do |x|! 7 x.report('amqp') do! 8 RUNS.times do! 9 response = AMQParty.get('amqp://test.simple/users.json')! 10 raise unless response.code == 200! 11 end! 12 end! 13 x.report('http') do! 14 RUNS.times do! 15 response = HTTParty.get('http://localhost:8080/users.json')! 16 raise unless response.code == 200! 17 end! 18 end! 19 end
44. REFERENCES Architecture: The Lost Years http://www.confreaks.com/videos/759- rubymidwest2011-keynote-architecture-the-lost- years Hexagonal Rails by Matt Wynne http://blog.mattwynne.net/category/hexagonal-rails/ Microservices by Martin Fowler and James Lewis http://martinfowler.com/articles/microservices.html Ruby AMQP Gem Docs http://rubyamqp.info/articles/guides.html RabbitMQ AMQP Concepts https://www.rabbitmq.com/tutorials/amqp- concepts.html HTTP Basics http://www3.ntu.edu.sg/home/ehchua/ programming/webprogramming/http_basics.html
45. Josh Szmajda - @jszmajda Ruby Hangout - @rubyhangout DCRUG Optoro, BLINQ.com http://github.com/rack-amqp/rack-amqp THANKS! Thanks John Nestoriak!