ecto-release-migrations

Original：🇺🇸 English

Translated

Set up database migrations for Elixir releases. Use when asked to configure release migrations, add migrate command to releases, or set up Ecto for production deployment without Mix.

3installs

Sourcegsmlg-dev/code-agent

Added on2026-04-27

NPX Install

npx skill4agent add gsmlg-dev/code-agent ecto-release-migrations

SKILL.md Content

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Ecto Release Migrations Setup

Overview

In Elixir releases, Mix is not available. This skill creates a Release module that handles database creation, migration, and rollback via

bin/app_name eval

commands.

Workflow

Detect app name and repos
- Check
```
mix.exs
```
  for app name
- Check
```
config/config.exs
```
  or
```
config/runtime.exs
```
  for Ecto repos
Create Release module
- Location:
```
lib/<app_name>/release.ex
```
- Must handle multiple repos if present
Verify config
- Ensure
```
config/runtime.exs
```
  has production database config
- Check for
```
DATABASE_URL
```
  or explicit config

Implementation

Release Module Template

elixir

defmodule <AppName>.Release do
  @moduledoc """
  Release tasks for database management.
  
  Usage in production:
    bin/<app_name> eval "<AppName>.Release.migrate()"
    bin/<app_name> eval "<AppName>.Release.rollback(<AppName>.Repo, 20240101000000)"
  """

  @app :<app_name>

  def migrate do
    load_app()

    for repo <- repos() do
      {:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :up, all: true))
    end
  end

  def rollback(repo, version) do
    load_app()
    {:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :down, to: version))
  end

  def create do
    load_app()

    for repo <- repos() do
      case repo.__adapter__().storage_up(repo.config()) do
        :ok -> IO.puts("Database created for #{inspect(repo)}")
        {:error, :already_up} -> IO.puts("Database already exists for #{inspect(repo)}")
        {:error, term} -> raise "Failed to create database: #{inspect(term)}"
      end
    end
  end

  def seed do
    load_app()
    
    for repo <- repos() do
      {:ok, _, _} = Ecto.Migrator.with_repo(repo, fn _repo ->
        seed_file = Application.app_dir(@app, "priv/repo/seeds.exs")
        if File.exists?(seed_file) do
          Code.eval_file(seed_file)
        end
      end)
    end
  end

  defp repos do
    Application.fetch_env!(@app, :ecto_repos)
  end

  defp load_app do
    Application.ensure_all_started(:ssl)
    Application.load(@app)
  end
end

For Phoenix Projects with Multiple Repos

If multiple repos exist (e.g.,

Repo

and

ReadRepo

), ensure

config.exs

has:

elixir

config :<app_name>, ecto_repos: [<AppName>.Repo, <AppName>.ReadRepo]

Verification Steps

After creating the module:

Compile:
```
mix compile
```

Test locally:

mix run -e "<AppName>.Release.migrate()"

Build release:
```
MIX_ENV=prod mix release
```

Test release:

_build/prod/rel/<app_name>/bin/<app_name> eval "<AppName>.Release.migrate()"

Usage Documentation

Add to project README or deployment docs:

bash

# Create database (first deploy only)
bin/<app_name> eval "<AppName>.Release.migrate()"

# Run migrations
bin/<app_name> eval "<AppName>.Release.migrate()"

# Rollback to specific version
bin/<app_name> eval "<AppName>.Release.rollback(<AppName>.Repo, 20240101000000)"

# Seed database
bin/<app_name> eval "<AppName>.Release.seed()"

Common Issues

SSL not started: Ensure
```
Application.ensure_all_started(:ssl)
```
is called before repo operations
App not loaded: Always call
```
Application.load(@app)
```
first
Missing ecto_repos config: Verify
```
config :app_name, ecto_repos: [...]
```
exists