Elixir API Cookbook

Install HEX, Phoenix and create app

# install hex
mix local.hex  
#install phoenix
mix archive.install hex phx_new

#create new app
mix phx.new crypto_api --database mysql

config Database at dev.exs

#config Database at dev.exs
config :crypto_api, CryptoApi.Repo,
  username: "root",
  password: "sua senha",
  database: "crypto_api_dev",
  hostname: "localhost",
  port: 9999,
  show_sensitive_data_on_connection_error: true,
  pool_size: 10

config Database at test.exs

config :crypto_api, CryptoApi.Repo,
  username: "root",
  password: "sua senha",
  database: "crypto_api_test#{System.get_env("MIX_TEST_PARTITION")}",
  hostname: "localhost",
  pool: Ecto.Adapters.SQL.Sandbox,
  port: 9999,
  pool_size: 10

Create Database and run server

mix ecto.create
mix phx.server

Create and seed Database

mix phx.gen.json Catalog Coin coins ticker:string:unique name:string price:decimal

# priv/repo/migrations/20211111180810_create_coins.exs
add :price, :decimal, precision: 20, scale: 10

mix ecto.migrate

Change priv/repo/seeds.exs:

alias CryptoApi.Repo
alias CryptoApi.Catalog.Coin

Repo.delete_all("coins")

Repo.insert!(%Coin{ticker: "BTC", name: "Bitcoin", price: 65432.12})
Repo.insert!(%Coin{ticker: "ETH", name: "Ethereum", price: 4765.30})
Repo.insert!(%Coin{ticker: "DOT", name: "Polkadot", price: 48.90})
Repo.insert!(%Coin{ticker: "ADA", name: "Cardano", price: 2.20})

mix run priv/repo/seeds.exs

Change the router.ex file:

scope "/", CryptoApiWeb do
  pipe_through(:api)

  resources("/coins", CoinController)
end

mix test

git push origin main

To production!

Create GCP Database

# run the database locally to run migrations
cloud_sql_proxy -instances=tests-322618:us-central1:crypto-api=tcp:3306

# run database create
SECRET_KEY_BASE=1234 MIX_ENV=prod DATABASE_URL=ecto://root@127.0.0.1:3306/crypto-api mix ecto.create
# run database migrate
SECRET_KEY_BASE=1234 MIX_ENV=prod DATABASE_URL=ecto://root@127.0.0.1:3306/crypto-api mix ecto.migrate
SECRET_KEY_BASE=1234 MIX_ENV=prod DATABASE_URL=ecto://root@127.0.0.1:3306/crypto-api mix run priv/repo/seeds.exs

Deploy to the GCP Cloud Run

Dockerfile

FROM bitwalker/alpine-elixir-phoenix:1.12.2

# Set mix env and ports
ENV MIX_ENV=prod
ENV PORT=4000

# Cache elixir deps

WORKDIR /app

COPY . .

RUN rm -rf _build && rm -rf .elixir_ls
RUN mix clean

RUN mix deps.get
RUN mix deps.compile

# Run frontend build, compile, and digest assets
# RUN cd assets/ && npm run deploy
# RUN mix do compile, phx.digest

CMD ["mix", "phx.server"]

cloudbuild.yaml

steps:
  # build the container image
- name: 'gcr.io/cloud-builders/docker'
  args: ['build', '-t', 'gcr.io/$PROJECT_ID/github.com/danicuki/crypto_api', '.']
  # push the container image to Container Registry
- name: 'gcr.io/cloud-builders/docker'
  args: ['push', 'gcr.io/$PROJECT_ID/github.com/danicuki/crypto_api']
  # Deploy container image to Cloud Run
- name: 'gcr.io/cloud-builders/gcloud'
  args: ['beta', 'run', 'deploy', 'crypto-api', 
  '--image', 'gcr.io/$PROJECT_ID/github.com/danicuki/crypto_api', 
  '--region', 'us-central1', '--allow-unauthenticated', '--port=4000', 
  '--add-cloudsql-instances=tests-322618:us-central1:crypto-api', 
  '--update-secrets=DATABASE_URL=crypto_api:latest,SECRET_KEY_BASE=crypto_api:latest']
images:
- gcr.io/$PROJECT_ID/github.com/danicuki/crypto_api

add to prod.exs

config :crypto_api, CryptoApi.Repo,
  database: "crypto-api",
  socket: "/cloudsql/tests-322618:us-central1:crypto-api"

Create secrets on GCP

echo ecto://root@34.133.36.129/crypto-api? > database_secret.txt
gcloud secrets create crypto_api --data-file database_secret.txt

Allow Secrets to Cloud Run

Setup Cloud Build

Set up a Cloud Build trigger Now you set up Cloud Build to build on every code change in your GitHub repository.

Go to the Cloud Build Triggers page in the Cloud Console.

Create a new trigger for your Phoenix app, following the on-screen prompts. On the Trigger settings page, set the Build configuration to Cloud Build configuration file; everything else can stay at the default values.

Deploy

git push origin main

Refining

Change coin view

defmodule CryptoApiWeb.CoinView do
  use CryptoApiWeb, :view
  alias CryptoApiWeb.CoinView

  def render("index.json", %{coins: coins}) do
    render_many(coins, CoinView, "coin.json")
  end

  def render("show.json", %{coin: coin}) do
    render_one(coin, CoinView, "coin.json")
  end

  def render("coin.json", %{coin: coin}) do
    %{
      id: coin.id,
      ticker: coin.ticker,
      name: coin.name,
      price: coin.price
    }
  end
end

Change Catalog GET to use ticker

# catalog.ex
def get_coin!(ticker), do: Repo.get_by!(Coin, ticker: ticker)