highly optimized elixir container builds

Dockerfile

@@ -1,16 +1,28 @@
 FROM "elixir:1.10.1-alpine"
 
+ARG MIX_ENV=dev
+ENV MIX_ENV=$MIX_ENV
+
 WORKDIR /code/
 
-RUN mix local.hex --force && mix local.rebar --force
+RUN echo "y" | mix local.hex --if-missing && echo "y" | mix local.rebar --if-missing
+
+ADD ["mix.lock", "mix.exs", "/code/"]
+
+RUN mix deps.get && MIX_ENV=test mix deps.compile && \
+  MIX_ENV=$MIX_ENV mix deps.compile
+
+ADD ["config", "lib", "priv", "/code/"]
+
+RUN MIX_ENV=$MIX_ENV mix compile
 
-COPY ["mix.lock", "mix.exs", "/code/"]
+ADD ["test", "/code/"]
 
-RUN mix deps.get
+RUN MIX_ENV=test mix compile && MIX_ENV=$MIX_ENV mix compile
 
 ADD . /code/
 
-RUN mix compile
+RUN MIX_ENV=test mix compile && MIX_ENV=$MIX_ENV mix compile
 
 CMD ["/bin/sh"]
 

docker-compose.yaml

@@ -16,6 +16,8 @@ services:
     build:
       context: .
       dockerfile: Dockerfile
+      cache_from:
+        - inakri/paper_trail:$CIRCLE_BRANCH
     environment:
       POSTGRES_USER: $POSTGRES_USER
       POSTGRES_PASSWORD: $POSTGRES_PASSWORD
@@ -35,6 +37,3 @@ networks:
   backend_network:
     driver: bridge
 
-# cache_from:
-#   - $BASE_IMAGE
-#   - $BACKEND_IMAGE_CACHE