# vim:set ft=dockerfile:
FROM alpine:3.12

ENV HAPROXY_VERSION 2.3.1
ENV HAPROXY_URL https://www.haproxy.org/download/2.3/src/haproxy-2.3.1.tar.gz
ENV HAPROXY_SHA256 8d3bf1252a5b60b21e9885c8d0d6d89e932d320c2977a6522aed6df81eefca4b

# see https://sources.debian.net/src/haproxy/jessie/debian/rules/ for some helpful navigation of the possible "make" arguments
RUN set -x \
	\
	&& apk add --no-cache --virtual .build-deps \
		gcc \
		libc-dev \
		linux-headers \
		lua5.3-dev \
		make \
		openssl \
		openssl-dev \
		pcre2-dev \
		readline-dev \
		tar \
		zlib-dev \
	\
	&& wget -O haproxy.tar.gz "$HAPROXY_URL" \
	&& echo "$HAPROXY_SHA256 *haproxy.tar.gz" | sha256sum -c \
	&& mkdir -p /usr/src/haproxy \
	&& tar -xzf haproxy.tar.gz -C /usr/src/haproxy --strip-components=1 \
	&& rm haproxy.tar.gz \
	\
	&& makeOpts=' \
		TARGET=linux-musl \
		USE_GETADDRINFO=1 \
		USE_LUA=1 LUA_INC=/usr/include/lua5.3 LUA_LIB=/usr/lib/lua5.3 \
		USE_OPENSSL=1 \
		USE_PCRE2=1 USE_PCRE2_JIT=1 \
		USE_ZLIB=1 \
		\
		EXTRA_OBJS=" \
# see https://github.com/docker-library/haproxy/issues/94#issuecomment-505673353 for more details about prometheus support
			contrib/prometheus-exporter/service-prometheus.o \
		" \
	' \
	&& nproc="$(getconf _NPROCESSORS_ONLN)" \
	&& eval "make -C /usr/src/haproxy -j '$nproc' all $makeOpts" \
	&& eval "make -C /usr/src/haproxy install-bin $makeOpts" \
	\
	&& mkdir -p /usr/local/etc/haproxy \
	&& cp -R /usr/src/haproxy/examples/errorfiles /usr/local/etc/haproxy/errors \
	&& rm -rf /usr/src/haproxy \
	\
	&& runDeps="$( \
		scanelf --needed --nobanner --format '%n#p' --recursive /usr/local \
			| tr ',' '\n' \
			| sort -u \
			| awk 'system("[ -e /usr/local/lib/" $1 " ]") == 0 { next } { print "so:" $1 }' \
	)" \
	&& apk add --no-network --virtual .haproxy-rundeps $runDeps \
	&& apk del --no-network .build-deps

# https://www.haproxy.org/download/1.8/doc/management.txt
# "4. Stopping and restarting HAProxy"
# "when the SIGTERM signal is sent to the haproxy process, it immediately quits and all established connections are closed"
# "graceful stop is triggered when the SIGUSR1 signal is sent to the haproxy process"
STOPSIGNAL SIGUSR1

COPY docker-entrypoint.sh /
ENTRYPOINT ["/docker-entrypoint.sh"]
CMD ["haproxy", "-f", "/usr/local/etc/haproxy/conf.d"]