How to run a mix task on Gigalixir using distillery #Elixir #Phoenix

0 - How to run a task

# Run task in development:
mix whatever

# Run task in staging/production:
gigalixir run bin/my_app whatever --app_name=...

config.exs

# /my_app/rel/config.exs
...

release :my_app do
  set version: current_version(:my_app)
  set applications: [
    :runtime_tools
  ]
  set commands: [
    migrate: "rel/hooks/pre_start/migrate.sh",
    seed: "rel/commands/seed.sh",
    whatever: "rel/commands/whatever.sh"
  ]
end

whatever.ex

# my_app/mix/tasks/whatever.ex

defmodule Mix.Tasks.Whatever do
  @moduledoc "Run in dev: `mix whatever; run in staging/prod: gigalixir run bin/my_app whatever --app_name=...`"

  use Mix.Task

  @start_apps [
    :crypto,
    :ssl,
    :postgrex,
    :ecto,
    :ecto_sql # If using Ecto 3.0 or higher
  ]

  @repos Application.get_env(:my_app, :ecto_repos, [])

  # Instead of calling `Mix.Task.run("app.start")` at the beginning of `run()`, use `start_services()` and `stop_services()` like in `release_tasks.ex`
  @shortdoc "Whatever this does"
  def run(_) do
    start_services()

    actual work

    stop_services()
  end

  defp start_services do
    IO.puts("Starting dependencies..")
    # Start apps necessary for executing migrations
    Enum.each(@start_apps, &Application.ensure_all_started/1)

    # Start the Repo(s) for app
    IO.puts("Starting repos..")

    # pool_size can be 1 for ecto < 3.0
    Enum.each(@repos, & &1.start_link(pool_size: 2))
  end

  defp stop_services do
    IO.puts("Success!")
    :init.stop()
  end
end

whatever.sh

# /my_app/rel/commands/whatever.sh

#!/bin/sh

release_ctl eval --mfa "Mix.Tasks.Whatever.run/1" --argv -- "$@"