Send connection types to NervesHub

Adds a callback to let the device have a hook for knowing that its
connected successfully to nerves hub. This allows sending connection
types up the socket after fully connected. Connection types are
"ethernet", "wifi", "cellular".

lib/nerves_hub_link/client.ex

@@ -76,6 +76,11 @@ defmodule NervesHubLink.Client do
   """
   @callback handle_error(any()) :: :ok
 
+  @doc """
+  Callback to perform an action when the device has connected to NervesHub.
+  """
+  @callback connected() :: :ok
+
   @doc """
   Callback to identify the device from NervesHub.
   """
@@ -139,6 +144,13 @@ defmodule NervesHubLink.Client do
     end
   end
 
+  @doc """
+  This function is called internally by NervesHubLink to notify clients of connecting to NervesHub.
+  """
+  def connected() do
+    apply_wrap(mod(), :connected, [])
+  end
+
   @doc """
   This function is called internally by NervesHubLink to identify a device.
   """

lib/nerves_hub_link/client/default.ex

@@ -49,6 +49,9 @@ defmodule NervesHubLink.Client.Default do
     Logger.warn("[NervesHubLink] error: #{inspect(error)}")
   end
 
+  @impl NervesHubLink.Client
+  def connected(), do: :ok
+
   @impl NervesHubLink.Client
   def identify() do
     Logger.info("[NervesHubLink] identifying")

lib/nerves_hub_link/socket.ex

@@ -40,6 +40,10 @@ defmodule NervesHubLink.Socket do
     GenServer.cast(__MODULE__, {:send_update_status, status})
   end
 
+  def send_connection_types(types) do
+    GenServer.cast(__MODULE__, {:send_connection_types, types})
+  end
+
   def check_connection(type) do
     GenServer.call(__MODULE__, {:check_connection, type})
   end
@@ -88,6 +92,7 @@ defmodule NervesHubLink.Socket do
   def handle_join(@device_topic, reply, socket) do
     Logger.debug("[#{inspect(__MODULE__)}] Joined Device channel")
     NervesHubLink.Connection.connected()
+    NervesHubLink.Client.connected()
     _ = handle_join_reply(reply)
     {:ok, socket}
   end
@@ -127,6 +132,11 @@ defmodule NervesHubLink.Socket do
     {:noreply, socket}
   end
 
+  def handle_cast({:send_connection_types, types}, socket) do
+    _ = push(socket, @device_topic, "connection_types", %{value: types})
+    {:noreply, socket}
+  end
+
   @impl Slipstream
   ##
   # Device API messages