Add Mv.Release.seed_admin for admin bootstrap from ENV

Creates/updates admin user from ADMIN_EMAIL and ADMIN_PASSWORD or ADMIN_PASSWORD_FILE.
Idempotent; no fallback password in production. Called from docker entrypoint and seeds.

lib/mv/release.ex

@@ -2,9 +2,22 @@ defmodule Mv.Release do
   @moduledoc """
   Used for executing DB release tasks when run in production without Mix
   installed.
+
+  ## Tasks
+
+  - `migrate/0` - Runs all pending Ecto migrations.
+  - `seed_admin/0` - Ensures an admin user exists from ENV (ADMIN_EMAIL, ADMIN_PASSWORD
+    or ADMIN_PASSWORD_FILE). Idempotent; can be run on every deployment or via shell
+    to update the admin password without redeploying.
   """
   @app :mv
 
+  alias Mv.Accounts
+  alias Mv.Accounts.User
+  alias Mv.Authorization.Role
+
+  require Ash.Query
+
   def migrate do
     load_app()
 
@@ -18,6 +31,128 @@ defmodule Mv.Release do
     {:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :down, to: version))
   end
 
+  @doc """
+  Ensures an admin user exists from ENV (ADMIN_EMAIL, ADMIN_PASSWORD or ADMIN_PASSWORD_FILE).
+
+  - If ADMIN_EMAIL is unset: no-op (idempotent).
+  - If ADMIN_PASSWORD (and ADMIN_PASSWORD_FILE) are unset and the user does not exist:
+    no user is created (no fallback password in production).
+  - If both ADMIN_EMAIL and ADMIN_PASSWORD are set: creates or updates the user with
+    Admin role and the given password. Safe to run on every deployment or via
+    `bin/mv eval "Mv.Release.seed_admin()"` to change the admin password without redeploying.
+  """
+  def seed_admin do
+    load_app()
+
+    admin_email = get_env("ADMIN_EMAIL", nil)
+    admin_password = get_env_or_file("ADMIN_PASSWORD", nil)
+
+    cond do
+      is_nil(admin_email) or admin_email == "" ->
+        :ok
+
+      is_nil(admin_password) or admin_password == "" ->
+        # Do not create or update any user without a password (no fallback in production)
+        :ok
+
+      true ->
+        ensure_admin_user(admin_email, admin_password)
+    end
+  end
+
+  defp ensure_admin_user(email, password) do
+    if is_nil(password) or password == "" do
+      :ok
+    else
+      do_ensure_admin_user(email, password)
+    end
+  end
+
+  defp do_ensure_admin_user(email, password) do
+    case Role.get_admin_role() do
+      {:ok, nil} ->
+        # Admin role does not exist (e.g. migrations not run); skip
+        :ok
+
+      {:ok, %Role{} = admin_role} ->
+        case get_user_by_email(email) do
+          {:ok, nil} ->
+            create_admin_user(email, password, admin_role)
+
+          {:ok, user} ->
+            update_admin_user(user, password, admin_role)
+
+          {:error, _} ->
+            :ok
+        end
+
+      {:error, _} ->
+        :ok
+    end
+  end
+
+  defp create_admin_user(email, password, admin_role) do
+    case Accounts.create_user(%{email: email}, authorize?: false) do
+      {:ok, user} ->
+        user
+        |> Ash.Changeset.for_update(:admin_set_password, %{password: password})
+        |> Ash.update!(authorize?: false)
+        |> then(fn u ->
+          u
+          |> Ash.Changeset.for_update(:update, %{})
+          |> Ash.Changeset.manage_relationship(:role, admin_role, type: :append_and_remove)
+          |> Ash.update!(authorize?: false)
+        end)
+
+        :ok
+
+      {:error, _} ->
+        :ok
+    end
+  end
+
+  defp update_admin_user(user, password, admin_role) do
+    user
+    |> Ash.Changeset.for_update(:admin_set_password, %{password: password})
+    |> Ash.update!(authorize?: false)
+    |> then(fn u ->
+      u
+      |> Ash.Changeset.for_update(:update, %{})
+      |> Ash.Changeset.manage_relationship(:role, admin_role, type: :append_and_remove)
+      |> Ash.update!(authorize?: false)
+    end)
+
+    :ok
+  end
+
+  defp get_user_by_email(email) do
+    User
+    |> Ash.Query.filter(email == ^email)
+    |> Ash.read_one(authorize?: false, domain: Mv.Accounts)
+  end
+
+  defp get_env(key, default) do
+    System.get_env(key, default)
+  end
+
+  defp get_env_or_file(var_name, default) do
+    file_var = "#{var_name}_FILE"
+
+    case System.get_env(file_var) do
+      nil ->
+        System.get_env(var_name, default)
+
+      file_path ->
+        case File.read(file_path) do
+          {:ok, content} ->
+            String.trim_trailing(content)
+
+          {:error, _} ->
+            default
+        end
+    end
+  end
+
   defp repos do
     Application.fetch_env!(@app, :ecto_repos)
   end