Mix.Tasks.Run works in test but crashes in prod

Questions / Help
1

Hi all.

I’m using Elixir/Phoenix v1.2.1.
Production Server is Ubuntu 16.04.2 LTS (AWS)
Test Server is Ubuntu 16.04.2 LTS (Azure)
DB Server is MySQL.

I created a task (priv/repo/reset_units.exs) that is supposed to run a DB update on server startup. Its code is simple as follows:

alias Myserver.Repo
alias Myserver.MyUnit

Repo.update_all(MyUnit, set: [online: false])

I also changed the start/2 function of lib/Myserver.ex including this:

Mix.Tasks.Run.run(["priv/repo/reset_units.exs"])
Logger.info ("[INIT] DB table updated.")

It runs fine on test server, but when I build the release and try to start it on production I get the following exception

[info] Application myserver exited: exited in: myserver.start(:normal, [])
    ** (EXIT) an exception was raised:
        ** (UndefinedFunctionError) function Mix.Tasks.Run.run/1 is undefined (module Mix.Tasks.Run is not available)
            Mix.Tasks.Run.run(["priv/repo/reset_units.exs"])
            (myserver) lib/myserver.ex:29: myserver.start/2
            (kernel) application_master.erl:273: :application_master.start_it_old/4

Does anybody had a similar issue?

Thanks!

2

You have code that is trying to access Mix somwhere, but Mix is the build system that is only available in the build area, it is not available in a release. Don’t use Mix from user code.

3

Got it, thanks.
Any suggestion on how I can I run that DB update on server startup?

4

Ecto has a Migration api to do that. That is what the mix ecto.migrate command ends up calling in to, just gotta do it yourself manually instead. :slight_smile: