Add basic forwarding/multiplexing functionality

lib/agent.ex

@@ -0,0 +1,69 @@
+defmodule Frajtano.Agent do
+  alias Frajtano.Peer
+  use GenServer
+
+  def start_link(args) do
+    GenServer.start_link(__MODULE__, nil, [{:name, __MODULE__} | args])
+  end
+
+  @impl true
+  def init(_) do
+    {:ok,
+     %{
+       keys: %{}
+     }}
+  end
+
+  @impl true
+  def handle_call({:identities}, _from, state) do
+    idents =
+      for(
+        {_, peer, :worker, _} <- DynamicSupervisor.which_children(Frajtano.Peer),
+        is_pid(peer),
+        do: peer
+      )
+      |> Task.async_stream(fn peer ->
+        with {:ok, idents} <- Peer.identities(peer),
+             do: {:ok, {idents, peer}}
+      end)
+      
+
+    # Double :ok-wrapping because of Task.async_stream
+    idents = (for {:ok, {:ok, {idents, peer}}} <- idents, do: {idents, peer})
+
+    {
+      :reply,
+      {:ok, for({idents, _} <- idents, ident <- idents, do: ident)},
+      %{
+        state
+        | keys:
+            for({idents, peer} <- idents, {key, _comment} <- idents, into: %{}, do: {key, peer})
+      }
+    }
+  end
+
+  @impl true
+  def handle_call({:sign, {key, _, _} = req}, _from, state) do
+    {:reply, Peer.sign(state.keys[key], req), state}
+  end
+
+  @impl true
+  def handle_call({:add_peer, path}, _from, state) do
+    case Peer.start(path) do
+      {:ok, _} -> {:reply, :ok, state}
+      {:error, error} -> {:reply, {:error, error}, state}
+    end
+  end
+
+  def identities(agent \\ __MODULE__) do
+    GenServer.call(agent, {:identities})
+  end
+
+  def sign(agent \\ __MODULE__, request) do
+    GenServer.call(agent, {:sign, request})
+  end
+
+  def add_peer(agent \\ __MODULE__, path) do
+    GenServer.call(agent, {:add_peer, path})
+  end
+end