Add Dockerfile

This commit adds a Dockerfile so Stringer can easily be ran in Docker.

For convenience there's a single container running both Unicorn as well
as cronjobs.
This goes a little against the Docker mantra of running only a single
process per container, but hey :-)

Author: pascalw

Dockerfile

@@ -0,0 +1,42 @@
+FROM ruby:2.3.3
+
+ENV RACK_ENV=production
+ENV PORT=8080
+
+EXPOSE 8080
+
+WORKDIR /app
+ADD Gemfile Gemfile.lock /app/
+RUN bundle install --deployment
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+      supervisor locales nodejs \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+RUN DEBIAN_FRONTEND=noninteractive dpkg-reconfigure locales \
+    && locale-gen C.UTF-8 \
+    && /usr/sbin/update-locale LANG=C.UTF-8
+
+ENV LC_ALL C.UTF-8
+
+ENV SUPERCRONIC_URL=https://github.com/aptible/supercronic/releases/download/v0.1.3/supercronic-linux-amd64 \
+    SUPERCRONIC=supercronic-linux-amd64 \
+    SUPERCRONIC_SHA1SUM=96960ba3207756bb01e6892c978264e5362e117e
+
+RUN curl -fsSLO "$SUPERCRONIC_URL" \
+ && echo "${SUPERCRONIC_SHA1SUM}  ${SUPERCRONIC}" | sha1sum -c - \
+ && chmod +x "$SUPERCRONIC" \
+ && mv "$SUPERCRONIC" "/usr/local/bin/${SUPERCRONIC}" \
+ && ln -s "/usr/local/bin/${SUPERCRONIC}" /usr/local/bin/supercronic
+
+ADD docker/supervisord.conf /etc/supervisord.conf
+ADD docker/start.sh /app/
+ADD . /app
+
+RUN useradd -m stringer
+RUN chown -R stringer:stringer /app
+USER stringer
+
+CMD /app/start.sh

docker/start.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env sh
+: ${FETCH_FEEDS_CRON:='*/5 * * * *'}
+: ${CLEANUP_CRON:='0 0 * * *'}
+
+cat <<EOF > /app/crontab
+$FETCH_FEEDS_CRON cd /app && bundle exec rake fetch_feeds
+$CLEANUP_CRON cd /app && bundle exec rake cleanup_old_stories
+EOF
+
+exec /usr/bin/supervisord -c /etc/supervisord.conf

docker/supervisord.conf

@@ -0,0 +1,16 @@
+[supervisord]
+nodaemon=true
+loglevel=debug
+
+[program:unicorn]
+command=bash -c 'bundle exec rake db:migrate && bundle exec unicorn -p $PORT -c ./config/unicorn.rb'
+directory=/app
+autostart=true
+autorestart=true
+redirect_stderr=true 
+stopsignal = QUIT
+
+[program:cron]
+command = /usr/local/bin/supercronic /app/crontab
+autostart=true
+autorestart=true