build: Dockerized application

.dockerignore

@@ -0,0 +1,36 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where 3rd-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+podcast_feed-*.tar
+
+# If NPM crashes, it generates a log, let's ignore it too.
+npm-debug.log
+
+# The directory NPM downloads your dependencies sources to.
+/assets/node_modules/
+
+# Since we are building assets from assets/,
+# we ignore priv/static. You may want to comment
+# this depending on your deployment strategy.
+rel/
+metadata.json
+.buildpacks

Dockerfile

@@ -0,0 +1,58 @@
+# ---- Build Stage ----
+FROM erlang:21 AS app_builder
+
+# Set environment variables for building the application
+ENV MIX_ENV=prod \
+    TEST=1 \
+    LANG=C.UTF-8
+
+# Fetch the latest version of Elixir (once the 1.9 docker image is available you won't have to do this)
+RUN set -xe \
+  && ELIXIR_DOWNLOAD_URL="https://github.com/elixir-lang/elixir/archive/v1.10.3.tar.gz" \
+  && ELIXIR_DOWNLOAD_SHA256="f3035fc5fdade35c3592a5fa7c8ee1aadb736f565c46b74b68ed7828b3ee1897" \
+  && curl -fSL -o elixir-src.tar.gz $ELIXIR_DOWNLOAD_URL \
+  && echo "$ELIXIR_DOWNLOAD_SHA256  elixir-src.tar.gz" | sha256sum -c - \
+  && mkdir -p /usr/local/src/elixir \
+  && tar -xzC /usr/local/src/elixir --strip-components=1 -f elixir-src.tar.gz \
+  && rm elixir-src.tar.gz \
+  && cd /usr/local/src/elixir \
+  && make install clean
+
+# Install hex and rebar
+RUN mix local.hex --force && \
+    mix local.rebar --force
+
+# Create the application build directory
+RUN mkdir /app
+WORKDIR /app
+
+# Copy over all the necessary application files and directories
+COPY config ./config
+COPY lib ./lib
+COPY priv ./priv
+COPY mix.exs .
+COPY mix.lock .
+
+# Fetch the application dependencies and build the application
+RUN mix deps.get
+RUN mix deps.compile
+RUN mix phx.digest
+RUN mix release
+
+# ---- Application Stage ----
+FROM debian:stretch AS app
+
+ENV LANG=C.UTF-8
+
+# Install openssl
+RUN apt-get update && apt-get install -y openssl
+
+# Copy over the build artifact from the previous step and create a non root user
+RUN useradd --create-home app
+WORKDIR /home/app
+COPY --from=app_builder /app/_build .
+RUN chown -R app: ./prod
+USER app
+
+# Run the Phoenix app
+CMD ["./prod/rel/podcast_feed/bin/podcast_feed", "start"]

config/prod.exs

@@ -16,8 +16,8 @@ config :podcast_feed, PodcastFeedWeb.Endpoint,
   cache_static_manifest: "priv/static/cache_manifest.json",
   server: true,
   root: ".",
-  version: Application.spec(:phoenix_distillery, :vsn),
-  force_ssl: [rewrite_on: [:x_forwarded_proto]]
+  version: Application.spec(:phoenix_distillery, :vsn)
+  # force_ssl: [rewrite_on: [:x_forwarded_proto]]
 
 config :podcast_feed,
   cache_duration: :timer.hours(24)

config/releases.exs

@@ -0,0 +1,10 @@
+import Config
+
+secret_key_base = System.fetch_env!("SECRET_KEY_BASE")
+application_port = System.fetch_env!("APP_PORT")
+application_host = System.fetch_env!("APP_HOST")
+
+config :podcast_feed, PodcastFeedWeb.Endpoint,
+  url: [scheme: "http", host: application_host, port: String.to_integer(application_port)],
+  http: [:inet6, port: String.to_integer(application_port)],
+  secret_key_base: secret_key_base

mix.exs

@@ -55,7 +55,7 @@ defmodule PodcastFeed.MixProject do
     [
       {:credo, "~> 1.4", only: [:dev, :test], runtime: false},
       {:dialyxir, "~> 1.0", only: [:dev], runtime: false},
-      {:excoveralls, "~> 0.7", only: [:dev, :test]}
+      {:excoveralls, "~> 0.7", only: [:dev, :test]},
     ]
   end