Clicking the Sign In link via local adapter causes Beam.smp to max out my CPU

[That-David-Guy]

Hi

Locally, the following happens:

1. Click sign in
2. fill out sign in form, e.g. test@test.com
3. go to dev/mailbox
4. click 'Open preview in separate tab`
5. Click 'Sign In'
6. I've sign in to my app, BUT I also notice that my CPU process 'beam.smp' jumps to 100+% and stays there.

I was expecting my CPU not to jump at all.

No other action on my site seems to cause a CPU spike.

I'm not even sure how to go about debugging this? Do you have any ideas?

I'm following this blog post https://elixircasts.io/passwordless-authentication-with-veil .

My config.exs file:

# //

# -- Veil Configuration    Don't remove this line
config :veil,
  site_name: "makeawesomeworkshop",
  email_from_name: "David Langford",
  email_from_address: "davidlangford@hey.com",
  sign_in_link_expiry: 12 * 3_600, # How long should emailed sign-in links be valid for?
  session_expiry: 86_400 * 30, # How long should sessions be valid for?
  refresh_expiry_interval: 86_400,  # How often should existing sessions be extended to session_expiry
  sessions_cache_limit: 250, # How many recent sessions to keep in cache (to reduce database operations)
  users_cache_limit: 100 # How many recent users to keep in cache

config :veil, Veil.Scheduler,
  jobs: [
    # Runs every midnight to delete all expired requests and sessions
    {"@daily", {Maw.Veil.Clean, :expired, []}}
  ]

# This is in dev.config and prod.secrect.config ~ David
# config :veil, MawWeb.Veil.Mailer,
#   adapter: Swoosh.Adapters.Sendgrid,
#   api_key: "your-api-key"

# -- End Veil Configuration

My config/dev.exs file

# //

# Passwordless Authentication
config :veil, MawWeb.Veil.Mailer,
  adapter: Swoosh.Adapters.Local

# //

My mix.exs file:

      elixir: "~> 1.5",
 {:phoenix, "~> 1.4.3"},
{:veil, github: "zanderxyz/veil"},

  def project do
    [
      app: :maw,
      version: "0.1.0",
      elixir: "~> 1.5",
      elixirc_paths: elixirc_paths(Mix.env()),
      compilers: [:phoenix, :gettext] ++ Mix.compilers(),
      start_permanent: Mix.env() == :prod,
      aliases: aliases(),
      deps: deps()
    ]
  end

  def application do
    [
      mod: {Maw.Application, []},
      extra_applications: [:logger, :runtime_tools]
    ]
  end

  defp elixirc_paths(:test), do: ["lib", "test/support"]
  defp elixirc_paths(_), do: ["lib"]

  defp deps do
    [
      {:bamboo, "~> 1.5"},
      {:phoenix, "~> 1.4.3"},
      {:phoenix_pubsub, "~> 1.1"},
      {:phoenix_ecto, "~> 4.0"},
      {:ecto_sql, "~> 3.0"},
      {:postgrex, ">= 0.0.0"},
      {:phoenix_html, "~> 2.11"},
      {:phoenix_live_reload, "~> 1.2", only: :dev},
      {:gettext, "~> 0.11"},
      {:jason, "~> 1.0"},
      {:plug_cowboy, "~> 2.0"},
      # Passwordless Authentication
      {:veil, github: "zanderxyz/veil"},
      # Waffle stuff below
      {:waffle, "~> 1.1.1"},
      {:ex_aws, "~> 2.1.2"},
      {:ex_aws_s3, "~> 2.0"},
      {:hackney, "~> 1.9"},
      {:sweet_xml, "~> 0.6"},
      {:waffle_ecto, "~> 0.0.9"}
      # Waffle stuff above
    ]
  end

  defp aliases do
    [
      "ecto.setup": ["ecto.create", "ecto.migrate", "run priv/repo/seeds.exs"],
      "ecto.reset": ["ecto.drop", "ecto.setup"],
      test: ["ecto.create --quiet", "ecto.migrate", "test"],
      releases: releases()
    ]
  end

  defp releases() do
    [
      hexpm: [
        include_executables_for: [:unix]
      ]
    ]
  end

[That-David-Guy]

If I comment out this line in session_controller.ex the CPU will not spike

# session_controller.ex file

  def create(conn, %{"request_id" => request_unique_id}) do
     # --
              # Commenting out the below line STOPS the CPU spiking
              Task.start(fn -> Veil.verify_user(user_id) end)
    # --

[That-David-Guy]

And checking the database, it looks like my user never actually verifies (the value in the verified column is FALSE)

[technicalcapt]

@That-David-Guy If you check on verify_user function, the return value from Cachex wasn't correct.

def verify_user(user_id) do
    case get_user(user_id) do
      {:ok, user} ->  # <-- change user to {:ok, user} it will fix the issue with verifying user and resolve the process trap error.
        verify_user(user)

      error ->
        error
    end
  end