Add redis image

redis/Dockerfile

@@ -0,0 +1,58 @@
+FROM alpine:3.6
+
+# add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
+RUN addgroup -S redis && adduser -S -G redis redis
+
+# grab su-exec for easy step-down from root
+RUN apk add --no-cache 'su-exec>=0.2'
+
+ENV REDIS_VERSION 3.2.9
+ENV REDIS_DOWNLOAD_URL http://download.redis.io/releases/redis-3.2.9.tar.gz
+ENV REDIS_DOWNLOAD_SHA 6eaacfa983b287e440d0839ead20c2231749d5d6b78bbe0e0ffa3a890c59ff26
+
+# for redis-sentinel see: http://redis.io/topics/sentinel
+RUN set -ex; \
+	\
+	apk add --no-cache --virtual .build-deps \
+		coreutils \
+		gcc \
+		linux-headers \
+		make \
+		musl-dev \
+	; \
+	\
+	wget -O redis.tar.gz "$REDIS_DOWNLOAD_URL"; \
+	echo "$REDIS_DOWNLOAD_SHA *redis.tar.gz" | sha256sum -c -; \
+	mkdir -p /usr/src/redis; \
+	tar -xzf redis.tar.gz -C /usr/src/redis --strip-components=1; \
+	rm redis.tar.gz; \
+	\
+# disable Redis protected mode [1] as it is unnecessary in context of Docker
+# (ports are not automatically exposed when running inside Docker, but rather explicitly by specifying -p / -P)
+# [1]: https://github.com/antirez/redis/commit/edd4d555df57dc84265fdfb4ef59a4678832f6da
+	grep -q '^#define CONFIG_DEFAULT_PROTECTED_MODE 1$' /usr/src/redis/src/server.h; \
+	sed -ri 's!^(#define CONFIG_DEFAULT_PROTECTED_MODE) 1$!\1 0!' /usr/src/redis/src/server.h; \
+	grep -q '^#define CONFIG_DEFAULT_PROTECTED_MODE 0$' /usr/src/redis/src/server.h; \
+# for future reference, we modify this directly in the source instead of just supplying a default configuration flag because apparently "if you specify any argument to redis-server, [it assumes] you are going to specify everything"
+# see also https://github.com/docker-library/redis/issues/4#issuecomment-50780840
+# (more exactly, this makes sure the default behavior of "save on SIGTERM" stays functional by default)
+	\
+	make -C /usr/src/redis -j "$(nproc)"; \
+	make -C /usr/src/redis install; \
+	\
+	rm -r /usr/src/redis; \
+	\
+	apk del .build-deps
+
+RUN mkdir /data && chown redis:redis /data
+VOLUME /data
+WORKDIR /data
+
+COPY docker-entrypoint.sh /usr/local/bin/
+ENTRYPOINT ["docker-entrypoint.sh"]
+
+RUN pwd
+COPY redis.conf /usr/local/redis
+
+EXPOSE 6379
+CMD ["redis-server", "/usr/local/redis/redis.conf"]