Erlport is undefined or private

Tormenator1

I’m still learning Elixir,and am making a basic elixir program to call a function from a python program. I am attempting to use erlport to do so. However, in the code below Erlport is undefined. I don’t see what could be causing it.

defmodule RarFile do
  @moduledoc """
  Documentation for `RarFile`.
  """

  @doc """
  Hello world.

  ## Examples

      iex> RarFile.hello()
      :world

  """
  

  def extractor(filepath) do
    {:ok, pid} = :erlport.open_port({:spawn, "python"}, [:binary, :stream, packet: 4])


  end

end

Here is the mix.exs file that I’m using.

defmodule RarFile.MixProject do
  use Mix.Project

  def project do
    [
      app: :rar_file,
      version: "0.1.0",
      elixir: "~> 1.14",
      start_permanent: Mix.env() == :prod,
      deps: deps()
    ]
  end

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      extra_applications: [:logger]
    ]
  end

  # Run "mix help deps" to learn about dependencies.
  defp deps do
    [

      {:erlport, "~> 0.10"}
      # {:dep_from_hexpm, "~> 0.3.0"},
      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
    ]
  end
end

15 comments

#python #troubleshooting #learning-elixir #erlport

0 1382 15

2023-05-21 16:54:12 UTC

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nallwhy

Hi, I’ve just released Doumi.Port - A helper library that facilitates the usage of Python in Elixir.

This library will make it much easier to use Python in Elixir.
Thanks!

Post #15

kokolegorille

No need to use charlist here, You can use binaries…

But it is only half of the problem, because the Python part is tricky to setup. You’ll need to do some conversion of data in the Python script. Something like this…

    if isinstance(path, bytes):
        path = path.decode("utf-8")
        if not os.path.exists(path):
            return ("error", "path does not exists.")
    else:
        return ("error", "cannot decode path.")

Post #14

dimitarvp

Move the variables inside the function.

Or if you want them to be accessible for the entire module, make them module attributes.

Post #13

Tormenator1

Thank you. Wrote a line in that format calling another function called rar_extraction. Here’s the total code I have so far

defmodule RarFile do

  archive_path = 'extractor/Kickassv301.cbr'
  destination_folder = 'extractor/extracted'


  def extractor(filepath) do
    {:ok, pi1} = :python.start()
    :python.call(pid1, :handler, :rar_extraction, [archive_path, destination_folder])

  end

end

However,I get a error from the ninth line that says

(CompileError) undefined function archive_path/0 (expected RarFile to define such a function or for it to be
imported, but none are available)

What could be causing this?

Post #12

kokolegorille

It should look like this…

Post #11

Tormenator1

So the python file is called handler.py and the function I am calling is called hey. It accepts 1 string parameter.

How would I call that function in this code. I’m unclear about what is meant to be passed into the call function in terms of the module parameter?

{:ok, pi1} = :python.start()
:python.call(pi1,,hey,"hi") #left module blank,unsure what is passed there

Post #10

kokolegorille

No, I did not provide code written in Erlang

Post #9

kokolegorille

Erlport is an Erlang package, so the doc is written in Erlang…

I advise You to read this page, if You want to translate from Erlang to Elixir

Post #8

Tormenator1

I am using this exact line when i get the error above.

:python.start([{:python_path, to_charlist(path)}, {:python, 'python3'}])

Elixir thinks that this is a syntax error.

I get a similar error when I try this line from the language docs

{ok, P} = python:start()

(SyntaxError) keyword argument must be followed by space after: python:
|
18 | {ok, P} = python:start()
| ^

Stacktrace:
│ (elixir 1.14.4) lib/kernel/parallel_compiler.ex:340: anonymous fn/5 in Kernel.ParallelCompiler.spawn_workers/7

Why exactly would this be happening?

Post #7