Building Modern Web Apps in Go Part 1

This was a presentation I gave at the Denver Go Meetup in September 2015.

My goal is to teach others and myself how to build a robust, modern web application in Go. My hope is that startups will turn to Go instead of Rails or Django when building web apps.

Disclaimer: This is an exploration. I am not an expert on the subject. I’ve built microservices in Go but have yet to build a monolith similar to Rails or Django.

Transcript

1. Building Modern Web Apps with Go Part 1 of a lot A Journey not a Destination
2. About Me — Lead Developer with CirrusMD — Skilled iOS developer — Experienced backend developer — (Ruby on Rails with Postgres) — Side project Go developer — Pretend Android developer — Hold-a-gun-to-my-head Javascript developer
3. More about me... — Serial Startup Engineer — Type safety and leaning on the compiler — I ♥ interfaces — Inheritance is the devil — Patterns and principles not frameworks
5. PRIMARY OBJECTIVE Convince startups to use Go for web apps
6. Why go with Go?
7. Go Success Stories
8. Docker
9. Personal Experiment Heroku free-tier + hobby PostgreSQL database Return an array of 1000 1-dimensional JSON objects from database Result: 50x throughput vs. Rails
10. Parse.com Push backend 50k connections per node to 1.5 million connections per node1 Integration test suite 25 minutes to 2 minutes1 Full deploy 30 minutes to 3 minutes1 1 http://blog.parse.com/learn/how-we-moved-our-api-from-ruby-to-go-and-saved-our- sanity/
11. Malwarebytes Scaled to 1 million requests per minute while uploading payloads to S3 without a worker instance2 (ie. no Sidekiq, Delayed Job, Redis, etc. Only Go concurrency primitives) 2 http://marcio.io/2015/07/handling-1-million-requests-per-minute-with-golang/
12. Sendgrid 140 Python servers to 1 Go Server3 3 Confirmed during Sept 2015 Gopher Meetup hosted by Sendgrid
13. The Free Lunch is Over4 i.e. Hardware won't make your code go faster 4 http://www.gotw.ca/publications/concurrency-ddj.htm
14. Startups can reap these benefits from the beginning.
15. What is a modern web app?
16. This is not a modern web app package main import "net/http" func main() { http.HandleFunc("/", hello) http.ListenAndServe(":8080", nil) } func hello(w http.ResponseWriter, r *http.Request) { w.Write([]byte("hello, world!")) }
17. Some components of a modern web app Routing, Middleware, Request Scoped Data, Authentication, Interfacing with a database, Asset Pipeline, Templates/Views, Static files, Graceful shutdown, Transactional Email
18. What's covered in this talk Building a Web App in Go — Project structure — Routing — Middleware
19. Not covered For future talks Request Scoped Data, Authentication, Domain Models, Asset Pipeline, Templates/Views, Static files, Graceful shutdown, Transactional Email
20. An Example of a Modern Web App Ruby on Rails and middleware
21. How NOT to do middleware Anatomy of a "mature" Rails app
22. class SomeController < SomeBaseController include Module1 include Module2 before_action :do_something_fun # Middleware is declared here # ... end
23. class SomeController < SomeBaseController # Or maybe it's in the base class include Module1 include Module2 before_action :do_something_fun # ... end
24. class SomeController < SomeBaseController include Module1 # Er, maybe it's in one of these modules? include Module2 before_action :do_something_fun # ... end
25. Or in the base class's superclass? Or the superclass's superclass? Or in a module mixed into the superclass?
26. Oh actually, it's in application.rb as Rack middleware config.middleware.use 'MySillyMiddleware' config.middleware.use 'GoodLuckFindingMe'
27. Or in one of several config/environment files... config/environments !"" development.rb !"" production.rb !"" staging.rb #"" test.rb
28. Or in any number of arbitrary initializers Rails.configuration.middleware.insert_before 0, IGuessIAmFirstMiddleWare Rails.configuration.middleware.use JustShoveMeAnywhereReally
30. Don't worry, there is a better way.
31. Go Web App Project Structure Inspired by Go tools Feedback encouraged
32. Don't do this app !"" assets !"" controllers !"" models #"" views WTF does this app do?
33. Perhaps like this Demonstrate in Vim
34. Routing Straight up plagiarized from Levi Cook's repo: https://github.com/levicook/foxsays
35. Middleware AKA request interceptors AKA filters AKA before, after, and around actions
36. Go's Solution type Middleware func(h http.Handler) http.Handler A function which returns a new handler that wraps the injected handler.
37. A Refresher // net/http package type Handler interface { ServeHTTP(ResponseWriter, *Request) }
38. func MyMiddleware(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { // Do stuff here AKA before filter/action h.ServeHTTP(w, r) }) }
39. func MyMiddleware(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { h.ServeHTTP(w, r) // Do stuff here AKA after filter }) }
40. func MyMiddleware(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { // Do stuff here h.ServeHTTP(w, r) // Then do stuff here aka around filter }) }
41. func MyMiddleware(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { defer func() { // guarantee stuff gets done at the very end }() h.ServeHTTP(w, r) }) }
42. Back to Vim
43. Third Party Middleware Solutions — https://github.com/justinas/alice — https://github.com/codegangsta/negroni
44. Quest for a Go web framework — Revel and Beego - too complicated, too much like Rails — Stop it with controllers. Handlers are just functions. — Wrong question. Libraries not frameworks.
46. Phoenix Framework Written by a Rails contributer in Elixer — Great concurrency — Functional, dynamic language — Runs on Erlang VM — Rails-like api, Elixer has Ruby-like syntax — Pipe operator is really cool
47. Thank you https://davidnix.io/post/buidling-modern-web-apps-in-go-part-1 This talk: https://github.com/DavidNix/modern-web-apps-in-go https://github.com/DavidNix/mware