Fixes #52

lib/mix/tasks/bonny.gen.dockerfile.ex

@@ -15,9 +15,13 @@ defmodule Mix.Tasks.Bonny.Gen.Dockerfile do
     {opts, _, _} =
       Mix.Bonny.parse_args(args, @default_opts, switches: @switches, aliases: @aliases)
 
+    binding = [
+      app_name: Mix.Bonny.app_dir_name()
+    ]
+
     "Dockerfile"
     |> Mix.Bonny.template()
-    |> EEx.eval_file([])
+    |> EEx.eval_file(binding)
     |> Mix.Bonny.render(opts[:out])
   end
 end

priv/templates/bonny.gen/Dockerfile

@@ -1,18 +1,33 @@
-FROM elixir:1.7.4-alpine
+#########################
+###### Build Image ######
+#########################
+
+FROM bitwalker/alpine-elixir:1.9.1 as builder
 
 ENV MIX_ENV=prod \
-    MIX_HOME=/opt/mix \
-    HEX_HOME=/opt/hex
+  MIX_HOME=/opt/mix \
+  HEX_HOME=/opt/hex
 
 RUN mix local.hex --force && \
-    mix local.rebar --force
+  mix local.rebar --force
 
 WORKDIR /app
 
 COPY . .
 
-RUN mix deps.get --only-prod && \
-    mix deps.compile && \
-    mix compile
+RUN mix deps.get --only-prod && mix release
+
+#########################
+##### Release Image #####
+#########################
+
+FROM alpine:3.10
+
+RUN apk add --update openssl ncurses
+
+WORKDIR /app
+COPY --from=builder /app/_build/prod/rel/<%= app_name %> ./
+RUN chown -R nobody: /app
 
-CMD ["mix", "run", "--no-halt"]
+ENTRYPOINT ["/app/bin/<%= app_name %>"]
+CMD ["start"]

test/mix/tasks/bonny.gen.dockerfile_test.exs

@@ -5,13 +5,13 @@ defmodule Mix.Tasks.Bonny.Gen.DockerfileTest do
   import ExUnit.CaptureIO
 
   describe "run/1" do
-    test "generates a Dockerfile" do
+    test "generates a Dockerfile using the application name" do
       output =
         capture_io(fn ->
           Dockerfile.run(["--out", "-"])
         end)
 
-      assert output =~ "FROM elixir"
+      assert output =~ "/app/_build/prod/rel/bonny"
     end
   end
 end