Rails Whenever Dockerfile Demo

• Simple whenever cron job:

every 1.minute do
  command "echo Hello >> /app/log/cron.log"
end

• Dockerfile :

FROM ruby:2.5

RUN apt-get update && \
    apt-get install -y cron && \
    rm -rf /var/lib/apt/lists/*

ENV LANG C.UTF-8
ENV RAILS_ENV production
ENV INSTALL_PATH /app

RUN mkdir $INSTALL_PATH && \
    mkdir log && touch /log/cron.log

ADD Gemfile Gemfile.lock ./

WORKDIR $INSTALL_PATH

RUN bundle install
COPY . .
RUN bundle exec whenever --update-crontab
CMD cron && rails server -e $stdout.sync=true

Container's Bash Result :