# ChannelWatcher

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[![docs](https://ik.imagekit.io/captech/channel-watcher/doc-coverage.svg)](https://hexdocs.pm/channel_watcher/)

A [GenServer](https://hexdocs.pm/elixir/GenServer.html) to monitor PIDs and run callbacks when they go down.

This is essentially a _slightly_ improved version of Chris McCord's answer to a [StackOverflow question](https://stackoverflow.com/a/33941469).

## Installation

The package can be installed by adding `channel_watcher` to your list of dependencies in `mix.exs`:

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

## Usage

Drop this in a module for a process you wish to test (such as a [Phoenix channel](https://hexdocs.pm/phoenix/channels.html)):

```elixir
:ok = ChannelWatcher.monitor(self(), {__MODULE__, CALLBACK, [ARGS]})
```

Make sure to replace `CALLBACK` with an atom of your callback function name, and `[ARGS]` with a list of arguments to pass to that callback.

The [test](https://gitlab.com/cap-public/packages/channel-watcher/-/blob/master/test/channel_watcher_test.exs) also shows an example of usage.