Update Dockerfile to use Alpine Linux (#169)

* Change base image to Alpine 3.11.3
* Use multi-stage build (reducing size from 276 MB to 9.5 MB)
* Change Makefile to build with -O3 instead of -O0 -ggdb

Dockerfile

@@ -1,14 +1,19 @@
-FROM debian:jessie
+FROM alpine:3.11.3 AS stage
 MAINTAINER Nicolas Favre-Felix <n.favrefelix@gmail.com>
 
-RUN apt-get -y update && apt-get -y upgrade && apt-get -y --force-yes install wget make gcc libevent-dev libmsgpack-dev redis-server
+RUN apk update && apk add wget make gcc libevent-dev msgpack-c-dev musl-dev bsd-compat-headers
 RUN wget https://github.com/nicolasff/webdis/archive/0.1.7.tar.gz -O webdis-0.1.7.tar.gz
 RUN tar -xvzf webdis-0.1.7.tar.gz
+RUN sed -i -e 's/-O0 -ggdb/-O3/g' ./webdis-0.1.7/Makefile
 RUN cd webdis-0.1.7 && make && make install && cd ..
-RUN rm -rf webdis-0.1.7 webdis-0.1.7.tag.gz
-RUN apt-get remove -y wget make gcc libevent-dev libmsgpack-dev
 RUN sed -i -e 's/"daemonize":.*true,/"daemonize": false,/g' /etc/webdis.prod.json
 
-CMD /etc/init.d/redis-server start && /usr/local/bin/webdis /etc/webdis.prod.json
+# main image
+FROM alpine:3.11.3
+RUN apk update && apk add libevent msgpack-c redis
+COPY --from=stage /usr/local/bin/webdis /usr/local/bin/
+COPY --from=stage /etc/webdis.prod.json /etc/webdis.prod.json
+RUN echo "daemonize yes" >> /etc/redis.conf
+CMD /usr/bin/redis-server /etc/redis.conf && /usr/local/bin/webdis /etc/webdis.prod.json
 
 EXPOSE 7379