Another option if you don’t want to have to edit your migrate def, is to ssh into your fly machine, start IEx, and then just call Ecto.Migrator.run(MyApp.Repo, :down, all: true). Then just do another release and your default migrate def will create your tables again. Steps below.

$fly ssh console
# app/bin/my_app remote
iex(my_app@5521219a)1> Ecto.Migrator.run(MyAPP.Repo, :down, all: true)

Hi @tadasajon! You are in the right direction, you can use the same technique recommended for running migrations:

defmodule MyApp.Release do
  def greet(), do: IO.puts "Hello World"
end

And then you can eval the code:

_build/prod/rel/my_app/bin/my_app eval "MyApp.Release.greet"

You can check the code inside those ecto tasks for more information on how to do it programmatically for you app release:

• mix ecto.drop
• mix ecto.create

TLDR; Take a look at Ecto.Adapters.Postgres.storage_down and Ecto.Adapters.Postgres.storage_up functions. You can see an example of how to do it in the test helper of this lib I’m working on.

This was super-helpful @thiagomajesk. Following your example, I was able to add the following function to lib/myapp/release.ex:

  def reset do
    load_app()
    Ecto.Adapters.Postgres.storage_down(Myapp.Repo.config())
    Ecto.Adapters.Postgres.storage_up(Myapp.Repo.config())
    migrate()
  end

and I have adjusted my fly.toml file to include these lines:

[deploy]
  release_command = "/app/bin/myapp eval Myapp.Release.reset"

But I’m unfortunately still hitting a snag. When I deploy my app the reset function runs as expected, but I get the following error:

{:error, "ERROR 55006 (object_in_use) database \"myapp\" is being accessed by other users\n\nThere are 11 other sessions using the database."}

I guess this is because I already have a previous version of my app up and running and it is holding some database connections.

I thought I could solve this by running fly suspend and bringing my app down for a few minutes, but after running fly suspend I am unable to run fly deploy, since I get the error:

Error App 'myapp' is currently suspended. Resume before deploying.

I’ll update here if I come up with a solution.