Playing with Elixir/Phoenix
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This document discusses developing a simple internal company website called Quote Pad using Elixir and Phoenix to learn the new technologies. The original version was built in 2012 using Ruby on Rails, but had issues like using SQLite in production and no moderation functionality. The new version uses Elixir, Phoenix, PostgreSQL, and improves the UI, adds moderation features, and migrates the existing data. The document outlines learning Elixir before Phoenix, common pitfalls to avoid like doing things in a non-Elixir way, and discusses deployment considerations like using Distillery and issues that can arise.
![Elixir:
def sum_list([head | tail], acc) do
sum_list(tail, head + acc)
end
def sum_list([], acc) do
acc
end
Non-Elixir:
sum = 0;
for (i=0; i<sizeof(array); i++)
sum += array[i]
Do Elixir stuff non-Elixir way](https://image.slidesharecdn.com/playingwithelixir2fphoenix1-180419125658/85/Playing-with-Elixir-Phoenix-29-320.jpg)
Playing with Elixir/Phoenix
- 1. Playing with Elixir/Phoenix Anton Sakharov, CTO @ MLSDev
- 5. This talk is not about Elixir syntax or Phoenix cool features
- 6. The best way to master new technology or framework is to develop something simple but not useless * IMHO
- 7. Internal company website: Quote Pad
- 8. ● Post quotes ● View quotes (latest / best) ● Vote for quotes (like / dislike) ● Email subscription to new quotes Features
- 9. Old Quote Pad ● Written in 2012 by iOS developer in order to learn Ruby on Rails ● Rails 3.2.6 ● SQLite in production ¯_(ツ)_/¯ ● Email/password authentication using Devise gem ● Non-responsive UI ● No moderation functionality ● No admin area/dashboard
- 10. New Quote Pad ● Elixir/Phoenix ● Authentication via Google Apps / G Suite / whatever they name it tomorrow ● Amazon RDS / PostgreSQL ● UI facelift, make it responsive ● Moderation, admin. dashboard, blah-blah-blah... ● Migrate data/content
- 12. Learning curve 1. Elixir 2. Phoenix 3. Libraries 4. Deployment 5. … 6. PROFIT!!!
- 13. First steps and things to avoid
- 14. Do not jump to Phoenix straight away Learn Elixir first
- 17. Do not learn Elixir and Phoenix by tutorials and videos only 1. You'll stay a Script Kiddie 2. Tutorials are probably outdated
- 19. This book is about Phoenix 1.2. Current Phoenix is 1.3; 1.4 is about to be released
- 21. Before you go on ...
- 23. Must-read documentation ● Elixir guides (mentioned earlier) ● Phoenix guides and docs ● Plug (Rack / Middleware in Rails world) ● Ecto (ActiveRecord in Rails world)
- 26. Pitfalls
- 27. ● Do Elixir stuff non-Elixir way ● Do Phoenix stuff Rails-way ● Tend to OOP ● Erlang OTP gives you a lot out of the box, keep it in mind ● On the other hand, there are not that many production-ready packages yet (like RubyGems) Pitfalls
- 28. Do Elixir stuff non-Elixir way Non-Elixir: list = Enum.map(1..100_000, &(&1 * 3)) list = Enum.filter(list, odd?) list = Enum.sum(list) Elixir: list = 1..100_000 |> Enum.map(&(&1 * 3)) |> Enum.filter(odd?) |> Enum.sum
- 29. Elixir: def sum_list([head | tail], acc) do sum_list(tail, head + acc) end def sum_list([], acc) do acc end Non-Elixir: sum = 0; for (i=0; i<sizeof(array); i++) sum += array[i] Do Elixir stuff non-Elixir way
- 30. Do Phoenix stuff kind of Rails-way defmodule User do schema "users" do # ... field :quote_count, :integer, virtual: true end # ... end # … def list_users(user, params) do page = User |> Repo.paginate(params) # Don't do this ;) %{page | entries: Enum.map(page, fn u -> %User{u | quote_count: Quotes.user_quote_count(u)} end)} end
- 31. OOP habits user.update(%{role: "admin"}) # this is not Elixir ;) Users.update(user, %{role: "admin"}) # this is!
- 32. What about background jobs ?
- 34. Not too many production-ready stuff available yet ● from simple things like URL validators ● to advanced like Devise for Rails
- 35. Bodyguard
- 36. Authorize plug
- 37. Data migration ● dump SQLite database: `sqlite3 dbname.sqlite3 .dump > dump.sql` ● remove `AUTOINCREMENT` ● varchar(255) -> `CHARACTER VARYING(255)` ● datetime -> `TIMESTAMP WITHOUT TIME ZONE` ● ` (backtick) -> ' (single quote) ● '' (empty string) -> `NULL` for empty date/time ● ...
- 40. Deployment ● Distillery ● edeliver ● .env ● nginx in reverse proxy mode ● SSL certificate ● Docker ● AWS ECS ● … ● WAIT!
- 43. rel/config.exs
- 45. Deployment pitfalls ● Erlang binaries: Mac OS X vs Linux ● Erlang versions: brew vs apt-get
- 47. ● t2.micro (1 GB RAM) fails to build Erlang from source: virtual memory exhausted ● it takes sooooo long to build Erlang from source… Deployment pitfalls
- 48. DEMO
- 50. Any questions?
- 51. Thank you!