How to create an application and run it another

Questions / Help
1

Hi, I’m unsure how to form the title of the question (or the question overall) so I’m writing the best I can.

Until a bit ago I’ve only made Phoenix applications which didn’t have any separated functionalities per se outside of the app scope. Everything was in that Phoenix application.

Now I want to create an application which runs as a Discord bot independently but maybe at a later point use Phoenix with it. But instead of turning my Elixir app into a Phoenix application eventually, I’d like to create my Elixir app, put it on GitHub and then eventually use a completely new Phoenix app and call my Discord app as a hex dependency and run it under applications in mix.exs.

I have no clue how to google this properly nor find any info which seperated a normal elixir app than an api app (or how do I call it).

2

Write your bot, publish it to hex, refer to it as dependency in the phoenix project.

Thats exactly how you do it. You already described it in your post.

3

I meant it as a more technical part. Should I make a file under lib/my_app/application.ex and add it in mix.exs as a mod application? Like so:

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      mod: {MyApp.Application, []},
      extra_applications: [:logger]
    ]
  end

I did use the Application module (behavior?) in MyApp.Application.

I just don’t know if that would work ahahahah.

4

Totally depends.

Do you want to have the bot in its own application supervision tree, single instance? Or do you want it to be used and started as a subtree in the “host” applications supervision tree?

If you want it to run its own tree you need a :mod entry, if you want it to be a subtree, you don’t need it.

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5

I actually want to make it run independently but could as well run if if was a dependency (specified in mix.exs), so I added it as a :mod entry. I think it is the appropriate solution, but, if it’s not I’ll be sure to update this thread!

6

Every application can be run as dependency, the :mod entry has nothing to do with it.

:mod only determines whether or not an application has an entrypoint and therefore its own supervision tree.

1 Like