# Compox

Compox starts Docker containers on demand.

Compox helps you to setup an ephemeral environment to run your tests using the
`docker-compose.yml` present in your project. After all your tests are done,
it will take the test environment down. This way your machine won't waste
resources having the containers running when they are not needed.

## Installation

Adding `compox` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:compox, "~> 0.1.0-beta3", only: [:test]}
  ]
end
```

## Usage

To use Compox follow these steps:

* Create a `docker-compose.yml` file with the containers that will be started
by this application.

* Ensure Compox starts all containers before running the tests:

```elixir
defp aliases do
  [
    test: ["compox.up", "ecto.create --quiet", "ecto.migrate --quiet", "test"]
  ]
end
```

* Edit your `test_helper.exs` to stop the containers after the tests are
done:

```elixir
ExUnit.after_suite(fn _ ->
  Compox.stop()
end)
```

### Example

Compox allows you to configure a project to start/stop the containers to run the
tests, but also provides configuration to **work with any kind of situation**.

For example, some of or coworkers prefer to have the containers running all the
time. In this case you want to ensure the docker containers are started before the test, so people that prefer to save resources will start the containers, but you will also won't to avoid to take containers down.

You `config/test.exs` file will look like:

```elixir
use Mix.Config

config :compox,
  auto_start: true,
  auto_stop: false,
  # Ensure Postgrex can connect to the db and throws an postgres error (catalog
  # unknown, invalid credentials...)
  container_upchecks: [
    "postgres-graphql": fn ->
      Postgrex.Protocol.connect(
        hostname: "localhost",
        database: "",
        username: "",
        types: nil
      )
      |> case do
        {:error, %{postgres: _}} -> :ok
        _ -> :error
      end
    end
  ]
```

The people who will want to stop the containers after test can use a [_dotenv_
library](https://github.com/BlakeWilliams/envy) to change the `auto_stop` config to `true` on their machines.

> This can work the other way around, start/stopping the containers always and
> having `dotfile` config to skipping the start/stop.