Ability to generate secret key with "docker run image_name gen_sessio…

…n_key"

Dockerfile

@@ -58,4 +58,7 @@ ENV APP_NAME=lib_ten
 ENV APP_VERSION=0.0.1
 ENV PORT 80
 
-CMD /app/bin/lib_ten foreground
+VOLUME /app/uploads
+
+ENTRYPOINT ["/app/bin/lib_ten"]
+CMD ["foreground"]

lib/lib_ten/release_tasks.ex

@@ -18,6 +18,18 @@ defmodule LibTen.ReleaseTasks do
     stop_services()
   end
 
+  def gen_random_key(key_length) do
+    :crypto.strong_rand_bytes(key_length)
+    |> Base.encode64
+    |> binary_part(0, key_length)
+  end
+
+  def print_random_key(length) do
+    {key_length, _} = Integer.parse(length)
+    gen_random_key(key_length)
+    |> IO.puts
+  end
+
   defp start_services do
     IO.puts("Loading #{@app}..")
     Application.load(@app)

rel/commands/gen_session_key.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+release_ctl eval --mfa "LibTen.ReleaseTasks.print_random_key/1" -- "64"

rel/config.exs

@@ -25,11 +25,9 @@ environment :prod do
 end
 
 release :lib_ten do
-  random_cookie_length = 128
-  random_cookie =
-    :crypto.strong_rand_bytes(random_cookie_length)
-    |> Base.encode64
-    |> binary_part(0, random_cookie_length)
+  set commands: [
+    gen_session_key: "rel/commands/gen_session_key.sh"
+  ]
 
   # NOTE:
   # Ideally we don't want to have any cookie here, so one will
@@ -39,6 +37,6 @@ release :lib_ten do
   # https://github.com/bitwalker/distillery/issues/428
   #
   # 😢
-  set cookie: random_cookie
+  set cookie: LibTen.ReleaseTasks.gen_random_key(128)
   set version: current_version(:lib_ten)
 end