# ExLoader

Load a single beam file, an app (a set of beams), or an erlang release (a set of apps) to a remote node. It is useful for distribute the binary to dynamically created remote node.

Things to do:

- [x] load ``sys.config`` to remote node
- [ ] better error logging if remote node failed to load modules or apps
- [ ] support upgrade release

## Installation

``ex_loader`` is available in [hex](https://hex.pm/packages/ex_loader), it can be installed
by adding `ex_loader` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [{:ex_loader, "~> 0.3.0"}]
end
```

## Usage

After adding ``ex_loader`` as a dependency, you can easily call the following API:

```elixir
# load a single module to a remote node, say "hello.beam" provide a func called ``say(msg)``
{:ok, module} = ExLoader.load_module("hello.beam", :"test-node@hostname")

# then the module is available. You can access it in remote node, or call it with RPC.
"hello world" = :rpc.call(:"test-node@hostname", module, :say, ["hello world"])

# load a list of apps from a release (generated by distillery). Say example_app.tar.gz contains an app called :example_app.
:ok = ExLoader.load_apps("example_app.tar.gz", [:example_app], :"test-node@hostname")

# now :example_app is started in :"test-node@hostname" (dependencies are resolved automatically). Let's assume this app will automatically start a GenServer called ExampleApp.Server, and it has a function ``hello(msg)``.
"hello world" = :rpc.call(:"test-node@hostname", ExampleApp.Server, :hello, ["world"])

# load a release. Say example_complex_app.tar.gz.
:ok = ExLoader.load_release("example_complex_app.tar.gz", :"test-node@hostname")

# all applications in this release are started in node :"test-node@hostname". The configuration ``sys.config`` in the release will be honored and loaded with ``Application.put_env`` so that you don't need to worry about configuration. If the release depends on environment variable, please set them before loading the release.
# you can interact with the functionality provided by the release now. Let's assume it contains an API server which handles the request to http://hostname:8888/hello/?msg=xxx.
{:ok, %HTTPoison.Response{body: "hello world"}} = HttpPoison.get("http://hostname:8888/hello/?msg=world")
```

Full documentation can be found at [https://hexdocs.pm/ex_loader](https://hexdocs.pm/ex_loader).