From 9bae951c555f9c25876968fa98853253b7007a0f Mon Sep 17 00:00:00 2001
From: kballou <kballou@devnulllabs.io>
Date: Fri, 24 Nov 2017 10:16:06 -0700
Subject: Level up the Echo Server

This should enable the upgrade process to retain connections

- Replace our simple task supervisor with a custom `simple_one_for_one`
  supervisor

- Upgrade the echo server to use a `GenServer` behaviour
---
 lib/octonetcat/servers/echo.ex | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

(limited to 'lib/octonetcat/servers/echo.ex')

diff --git a/lib/octonetcat/servers/echo.ex b/lib/octonetcat/servers/echo.ex
index e416d9d..8ad6aff 100644
--- a/lib/octonetcat/servers/echo.ex
+++ b/lib/octonetcat/servers/echo.ex
@@ -6,23 +6,27 @@ defmodule Octonetcat.Echo do
   dies on failure or disconnect.
   """
 
+  use GenServer
   require Logger
 
-  def serve(socket) do
-    socket
-    |> read_line()
-    |> write_line!(socket)
+  def start_link(socket) do
+    GenServer.start_link(__MODULE__, socket)
+  end
 
-    serve(socket)
+  def init(socket) do
+    :ok = :inet.setopts(socket, active: true)
+    {:ok, %{socket: socket}}
+  end
+
+  def handle_info({:tcp, _, msg}, state = %{socket: socket}) do
+    msg
+    |> write_line!(socket)
+    {:noreply, state}
   end
 
-  def read_line(socket) do
-    case :gen_tcp.recv(socket, 0) do
-      {:ok, line} -> line
-      {:error, reason} ->
-        Logger.error(reason)
-        Process.exit(self(), :normal)
-    end
+  def handle_info({:tcp_closed, _}, _state) do
+    Logger.info("#{__MODULE__}: Connection closing...")
+    {:stop, :normal, %{}}
   end
 
   def write_line!(line, socket) do
-- 
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