pokemon.trade/Dockerfile

FROM ruby:2.6.3-alpine AS base

ARG BUILD_PACKAGES="build-base git"
ARG DEV_PACKAGES="postgresql-dev yarn"
ARG RUBY_PACKAGES="tzdata"

RUN apk update && \
      apk add --no-cache $BUILD_PACKAGES $DEV_PACKAGES $RUBY_PACKAGES

RUN mkdir /app
WORKDIR /app

################################################################################
FROM base AS builder

# Copying the Gemfile separately allows the image to be cached.
# These steps are not rerun unless the Gemfile or Gemfile.lock is changed.
COPY Gemfile Gemfile.lock /app/
RUN bundle install --jobs 4 --retry 5

# Again, copy seperately so we can cache this step.
COPY package.json yarn.lock /app/
RUN yarn install && yarn cache clean

# Copy our app over now
COPY . /app

# Copy the docker configuration to the correct location
COPY config/database.yml.docker config/database.yml

# Compile our assets, moving unneeded directories out of way for the prod image
# after compilation has completed.
RUN rails assets:precompile && \
      rm -rf tmp/cache log && \
      mkdir -p /var/cache/app/app && \
      mv node_modules spec /var/cache/app && \
      mv app/assets /var/cache/app/app

################################################################################
FROM base AS dev

COPY --from=builder /usr/local/bundle/ /usr/local/bundle/
COPY --from=builder /app/ /app/
COPY --from=builder /var/cache/app/ /app/

################################################################################
# We want a tiny image, so don't start from base
FROM ruby:2.6.3-alpine AS prod

ENV RAILS_ENV=production
RUN apk add --update --no-cache $RUBY_PACKAGES

RUN mkdir /app
WORKDIR /app

# (Re)install only dependencies we need for prod instead of copying everything
# from the builder
COPY --from=builder /usr/local/bundle/ /usr/local/bundle/
# Grab the app with all compiled assets and docker configuration from builder
COPY --from=builder /app/ /app/

# Run the server
EXPOSE 3000
CMD ["rails", "server", "-b", "0.0.0.0"]