phx_custom

# Dockerfile for Phoenix project.

# > Global args
# https://github.com/moby/moby/issues/37345#issuecomment-400245466

# customizable args
ARG RELEASE_NAME=<%= @project_name %>
ARG PORT=4000
ARG HEALTHCHECK_PATH=/health-check

# internal args
ARG MIX_ENV=prod
ARG WORK_DIR=/app
ARG ASSETS_DIR=assets


# > Prepare
FROM elixir:1.11-alpine AS release-assembler

# args
ARG MIX_ENV
ARG WORK_DIR
ARG ASSETS_DIR

# envs
ENV MIX_ENV $MIX_ENV

# preparation
RUN mkdir -p $WORK_DIR
WORKDIR $WORK_DIR

RUN apk add --no-cache \
  build-base \
  git \
  nodejs \
  nodejs-npm

# install mix dependencies
RUN mix local.hex --force
RUN mix local.rebar --force
COPY mix.exs mix.lock ./
COPY config config/
RUN mix deps.get --only $MIX_ENV

# install npm dependencies
COPY $ASSETS_DIR/package.json $ASSETS_DIR/
COPY $ASSETS_DIR/package-lock.json $ASSETS_DIR/
RUN npm install --prefix $ASSETS_DIR

# compile deps (cache as much as possible)
RUN mix deps.compile

# copy source code
COPY . ./

# compile
RUN mix compile

# digest and compress assets
RUN npm run deploy --prefix $ASSETS_DIR
RUN mix phx.digest

# assemble release
RUN mix release


# > Final
FROM elixir:1.11-alpine

# args
ARG MIX_ENV
ARG WORK_DIR
ARG RELEASE_NAME
ARG PORT
ARG HEALTHCHECK_PATH

# envs
ENV HOME $WORK_DIR
ENV RELEASE_NAME $RELEASE_NAME
ENV PORT $PORT
ENV HEALTHCHECK_PATH $HEALTHCHECK_PATH

# preparation
RUN mkdir -p $WORK_DIR
WORKDIR $WORK_DIR

RUN apk add --no-cache \
  curl \
  inotify-tools && \
  update-ca-certificates --fresh

# copy release
COPY --from=release-assembler \
  --chown=nobody:nobody \
  $WORK_DIR/_build/$MIX_ENV ./

# limit permissions
USER nobody:nobody

# health check
HEALTHCHECK --start-period=30s --interval=5s --timeout=3s --retries=3 \
  CMD curl -o /dev/null -s -f http://localhost:$PORT$HEALTHCHECK_PATH

EXPOSE $PORT
ENTRYPOINT ./rel/$RELEASE_NAME/bin/$RELEASE_NAME start