# `Membrane.ResourceGuard`
[🔗](https://github.com/membraneframework/membrane-core/blob/v1.3.0/lib/membrane/resource_guard.ex#L1)

Utility for handling resources that must be cleaned up after use.

This utility uses a separate process that allows registering functions
that are called when the owner process (passed to `start_link/1`) dies for
any reason. Each Membrane component spawns its resource guard on startup
and provides it via callback context.

### Example

    def handle_setup(ctx, state) do
      resource = MyResource.create()

      Membrane.ResourceGuard.register(ctx.resource_guard, fn ->
        MyResource.cleanup(resource)
      end)

      {:ok, %{state | my_resource: resource}}
    end

# `t`

```elixir
@type t() :: pid()
```

Utility for handling resources that must be cleaned up after use

# `child_spec`

Returns a specification to start this module under a supervisor.

See `Supervisor`.

# `cleanup`

```elixir
@spec cleanup(t()) :: :ok
```

Executes all cleanup functions registered in the resource gurard.

# `cleanup`

```elixir
@spec cleanup(t(), tag :: any()) :: :ok
```

Executes cleanup functions registered with the specifc tag.

If many cleanup functions are registered with the same tag, all of them are executed.

# `register`

```elixir
@spec register(
  t(),
  (-> any()),
  opts :: [tag: any(), timeout: milliseconds :: non_neg_integer()]
) :: tag
when tag: any()
```

Registers a resource cleanup function in the resource guard.

Registered functions are called in the order reverse to the registration order.
Function returns a tag of the registered cleanup function. Tag can be passed
under a `:tag` key in `opts`. Many functions can be registered with the same tag.
If there is no `:tag` key in `opts`, tag will be result of `make_ref()`.

# `start_link`

```elixir
@spec start_link(owner_pid :: pid()) :: {:ok, t()}
```

# `unregister`

```elixir
@spec unregister(t(), tag :: any()) :: :ok
```

Unregisters a resource cleanup function from the resource guard.

All cleanup functions with tag `tag` are deleted.

---

*Consult [api-reference.md](api-reference.md) for complete listing*