Dockerfile.web

FROM ruby:3.1.1-alpine3.13

ARG APP_PATH=/myapp
ARG APP_USER=appuser
ARG APP_GROUP=appgroup
ENV RAILS_ENV production
ENV RAILS_SERVE_STATIC_FILES true 
# ^ (unless nginx, etc.. is used)
ENV RAILS_LOG_TO_STDOUT true

RUN apk add --update \
    --no-cache bash \
    build-base \
    git \
    postgresql-dev \
    postgresql-client && \
  addgroup -S $APP_GROUP && \

  adduser -S -s /sbin/nologin -G $APP_GROUP $APP_USER && \
  # The /sbin/nologin command politely refuse a login. It displays a message that 
  # an account is not available and exits non-zero. This is prefreed method these 
  # days to deny login access to account.

  mkdir $APP_PATH && \
  chown $APP_USER:$APP_GROUP $APP_PATH

WORKDIR $APP_PATH
# Add a script to be executed every time the container starts.
COPY entrypoint.sh /usr/bin/
RUN chmod +x /usr/bin/entrypoint.sh
COPY --chown=$APP_USER:$APP_GROUP Gemfile* $APP_PATH/
# The command chown, an abbreviation of change owner, is used on 
# Unix and Unix-like operating systems to change the owner of 
# file system files, directories.
RUN bundle install
USER $APP_USER
COPY --chown=$APP_USER:$APP_GROUP . $APP_PATH/
ENTRYPOINT ["entrypoint.sh"]
EXPOSE 3000
# Start the main process.
CMD ["rails", "server", "-b", "0.0.0.0"]