# KantanCluster

[![Hex version](https://img.shields.io/hexpm/v/kantan_cluster.svg 'Hex version')](https://hex.pm/packages/kantan_cluster)
[![API docs](https://img.shields.io/hexpm/v/kantan_cluster.svg?label=docs 'API docs')](https://hexdocs.pm/kantan_cluster)
[![CI](https://github.com/mnishiguchi/kantan_cluster/actions/workflows/ci.yml/badge.svg)](https://github.com/mnishiguchi/kantan_cluster/actions/workflows/ci.yml)

Form a simple Erlang cluster easily in Elixir.

Documentation can be found at [https://hexdocs.pm/kantan_cluster](https://hexdocs.pm/kantan_cluster).

### Getting started

Add `kantan_cluster` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:kantan_cluster, "~> 0.1.0"}
  ]
end
```

Start a `KantanCluster` server, which will start a node and connect it to specified nodes using a specified [Erlang magic cookie].

```elixir
KantanCluster.start(
  node: {:longnames, :"node1@127.0.0.1"},
  cookie: :hello,
  connect_to: [:"nerves@nerves-mn00.local"]
)
```

Options:

* `:node` - a name of the node that you want to start (default: `{:longnames, :"xxxx@127.0.0.1"}` where `xxxx` is a random string)
* `:cookie` - [Erlang magic cookie] to form a cluster (default: random cookie)
* `:connect_to` - a list of nodes you want to connected to (default: `[]`)

Alternatively, options can be loaded from your `config/config.exs`.

```elixir
config :kantan_cluster,
  node: {:longnames, :"node1@127.0.0.1"},
  cookie: :hello,
  connect_to: [:"nerves@nerves-mn00.local"]
```

`KantanCluster` starts a server that monitors the connection per node name under a dynamic supervisor.

![](https://user-images.githubusercontent.com/7563926/139163607-704c0352-64ff-47f3-8697-9958654c27b4.png)

`kantan_cluster` monitors all the connected nodes and attempts to reconnect them automatically in case they get disconnected.

![](https://user-images.githubusercontent.com/7563926/138617820-562b8102-c478-424d-bfaa-e15abf08a722.png)

You can connect or disconnect a node on demand.

```elixir
KantanCluster.connect(:"nerves@nerves-mn01.local")

KantanCluster.disconnect(:"nerves@nerves-mn01.local")
```

<!-- Links -->

[Erlang magic cookie]: https://erlang.org/doc/reference_manual/distributed.html#security