LiveReloading chapter: server fails to start

[belgoros]

I followed the Pluralsight course and was stopped in the Live Reloading chapter where you starter the Phoenix server:

The dips.exs file in rsvp_web app looks like that:

defp deps do
    [
      {:phoenix, "~> 1.4.16"},
      {:phoenix_pubsub, "~> 1.1"},
      {:phoenix_html, "~> 2.11"},
      {:phoenix_live_reload, "~> 1.2", only: :dev},
      {:gettext, "~> 0.11"},
      {:jason, "~> 1.0"},
      {:plug_cowboy, "~> 2.0"}
    ]
  end

Running mix dips.get on the project root didn't solve the problem.

Are there any updates regarding this issue?
I'm using Elixir 1.10.2 and phoenix, "~> 1.4.16 versions at macOS.

[taylonr]

Is `Jason` the name of the module you created? Looks like it can't find that module. Also down in the first line of the error message it says that Poison isn't loaded and could not be found. Can you verify that it is in your mix.exs file? I don't know which of these two modules is causing the other failure, but that's where I'd start.

…

On Mon, Apr 20, 2020 at 8:24 AM Serguei Cambour ***@***.***> wrote: I followed the Pluralsight course <https://www.pluralsight.com/courses/phoenix-getting-started> and was stopped in the *Live Reloading* chapter where you starter the Phoenix server: [image: Screenshot 2020-04-20 at 15 19 26] <https://user-images.githubusercontent.com/83579/79756427-e43fdb80-831a-11ea-8dd7-ba194d0b1e1e.png> Are there any updates regarding this issue? I'm using Elixir 1.10.2 and phoenix, "~> 1.4.16 versions at macOS. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#2>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAHCVE2YCCQTLAUN7FKGKHLRNREKHANCNFSM4MMOBI4Q> .

[belgoros]

Here are the steps I followed during the cource and the errors raised when executing the requested commands:

• mix new rsvp_umbrella --umbrella, - OK
• cd rsvp_umbrella/apps, - OK
• mix new rsvp --sup, - OK
• mix phoenix.new rsvp_web --no-ecto, - FAILS with:

  ** (Mix) The task "phoenix.new" could not be found
  Note no mix.exs was found in the current directory
  

  It seems like the right task to run for the latest Phoenix version (1.4.16) would be:

  mix phx.new.web rsvp_web --no-ecto
  

• so run mix phx.new.web rsvp_web --no-ecto: OK
• add ecto, postgrex to rsvp/mix.exs. file
• cd to rsvp_umbrella and run mix deps.get to install dependencies
• create a new config.exs in rsvp/config folder (it DID NOT EXIST)
• add the missing import Config in the top of the file, followed by the database settings:

config :rsvp, Rsvp.Repo,
  adapter: Ecto.Adapters.Postgres,
  database: "rsvp",
  username: "postgres",
  password: "postgres"

• create repo.ex in rsvp/lib folder with the following content:

defmodule Rsvp.Repo do
  use Ecto.Repo, otp_app: :rsvp
end

• move repo.ex to the rsvp/lib/rsvp folder to respect the module naming structure
• add ecto repos to the rsvp/config/config.exs file:

config :rsvp, ecto_repos: [Rsvp.Repo]

• declare children in rsvp/lib/rsvp.ex- FAILS, because the RIGHT file to be update is rsvp/lib/rsvp/application.ex (correct me if I'm wrong):

defmodule Rsvp.Application do
  # See https://hexdocs.pm/elixir/Application.html
  # for more information on OTP Applications
  @moduledoc false

  use Application

  def start(_type, _args) do
    children = [
      # Starts a worker by calling: Rsvp.Worker.start_link(arg)
      # {Rsvp.Worker, arg}
      worker(Rsvp.Repo, [])
    ]

    # See https://hexdocs.pm/elixir/Supervisor.html
    # for other strategies and supported options
    opts = [strategy: :one_for_one, name: Rsvp.Supervisor]
    Supervisor.start_link(children, opts)
  end
end

• cd to rsvp_umbrella and run mix compile, - FAILS, you will get an error:

rsvp_umbrella git:(master) mix compile
==> rsvp
Compiling 2 files (.ex)

== Compilation error in file lib/rsvp/application.ex ==
** (CompileError) lib/rsvp/application.ex:12: undefined function worker/2
    (elixir 1.10.2) src/elixir_locals.erl:114: anonymous fn/3 in :elixir_locals.ensure_no_undefined_local/3
    (stdlib 3.12) erl_eval.erl:680: :erl_eval.do_apply/6

It seems like the error comes from calling worker(Rsvp.Repo, []).

• Changing the children as follows:

def start(_type, _args) do
    children = [
      # Starts a worker by calling: Rsvp.Worker.start_link(arg)
      # {Rsvp.Worker, arg}
      {Rsvp.Repo, []}
    ]
...

and running mix compile raised another error coming this time from Rsvp.Repo module:

== Compilation error in file lib/rsvp/repo.ex ==
** (ArgumentError) missing :adapter option on use Ecto.Repo
    lib/ecto/repo/supervisor.ex:66: Ecto.Repo.Supervisor.compile_config/2
    lib/rsvp/repo.ex:2: (module)
    (stdlib 3.12) erl_eval.erl:680: :erl_eval.do_apply/6

What is the right way to declare a worker at this step?
What am I missing here?

[taylonr]

Ah, it could be the difference between latest Phoenix (1.4) and the version the course used (1.2)

The course came out right before 1.3, where some of the changes occurred, including umbrella projects and the change from mix phoenix.new to mix phx.new. However, the structural changes were incorporated in the course, but the mix commands were not.

And I'd guess other projects like Ecto etc have made breaking changes in 1.3 or 1.4 compared to 1.2 and that's why you're seeing things like missing an :adapter atom on Ecto.Repo

[belgoros]

Ok, thank you for your feedback. It's so disappointing to see most of Elixir/Phoenix courses not to updating their content... By chance, Pluralsight offered a FREE month subscription for April 2020 due to COVID-19. So it would even more frustrating to pay money for something outdated...

[taylonr]

The "Getting Started With Elixir" is up to date, I think the updates for 1.10 went live 2 months ago. That said, if you use 1.2 and the versions of the library mentioned in the course, it should still give you a good starting point for how to use Phoenix until it can be updated.

…

On Tue, Apr 21, 2020 at 8:07 AM Serguei Cambour ***@***.***> wrote: Ok, thank you for your feedback. It's so disappointing to see most of Elixir/Phoenix courses not to updating their content... By chance, Pluralsight offered a FREE month subscription for April 2020 due to COVID-19. So it would even more frustrating to pay money for something outdated... — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#2 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAHCVE6NOHJYUMC4GY42EE3RNWLBFANCNFSM4MMOBI4Q> .

[taylonr]

That said, I do understand the frustration of something not working out of the box when you're following along.

I'll take a look and see what all needs to be updated in the course.

[belgoros]

Oh, that would be really awesome 👍 , thank you!