Convert central-controller docker build to use a builder subcontainer

ext/central-controller-docker/Dockerfile

@@ -1,19 +1,26 @@
 # Dockerfile for ZeroTier Central Controllers
-FROM centos:7
+FROM centos:7 as builder
 MAINTAINER Adam Ierymekno <adam.ierymenko@zerotier.com>, Grant Limberg <grant.limberg@zerotier.com>
 
+ARG git_branch=master
+
 RUN yum update -y
 RUN yum install -y https://download.postgresql.org/pub/repos/yum/10/redhat/rhel-7-x86_64/pgdg-centos10-10-2.noarch.rpm
-RUN yum install -y bash postgresql10 libpqxx-devel
-
 RUN yum -y install epel-release && yum -y update && yum clean all
-RUN yum -y install clang jemalloc jemalloc-devel
+RUN yum groupinstall -y "Development Tools"
+RUN yum install -y bash postgresql10 postgresql10-devel libpqxx-devel glibc-static libstdc++-static clang jemalloc jemalloc-devel
 
+RUN git clone http://git.int.zerotier.com/zerotier/ZeroTierOne.git
+RUN if [ "$git_branch" != "master" ]; then cd ZeroTierOne && git checkout -b $git_branch origin/$git_branch; fi
+RUN ldconfig
+RUN cd ZeroTierOne && make central-controller
+
+FROM centos:7
 
-ADD zerotier-one /usr/local/bin/zerotier-one
+COPY --from=builder /ZeroTierOne/zerotier-one /usr/local/bin/zerotier-one
 RUN chmod a+x /usr/local/bin/zerotier-one
 
-ADD docker/main.sh /
+ADD ext/central-controller-docker/main.sh /
 RUN chmod a+x /main.sh
 
 ENTRYPOINT /main.sh

make-linux.mk

@@ -334,8 +334,8 @@ docker:	FORCE
 central-controller:	FORCE
 	make -j4 LDLIBS="-L/usr/pgsql-10/lib/ -lpq -Lext/librabbitmq/centos_x64/lib/ -lrabbitmq" CXXFLAGS="-I/usr/pgsql-10/include -I./ext/librabbitmq/centos_x64/include -fPIC" DEFS="-DZT_CONTROLLER_USE_LIBPQ -DZT_CONTROLLER" ZT_OFFICIAL=1 ZT_USE_X64_ASM_ED25519=1 one
 
-central-controller-docker:	central-controller
-	docker build -t docker.zerotier.com/zerotier-central/ztcentral-controller:${TIMESTAMP} -f ext/central-controller-docker/Dockerfile .
+central-controller-docker: FORCE
+	docker build -t docker.zerotier.com/zerotier-central/ztcentral-controller:${TIMESTAMP} -f ext/central-controller-docker/Dockerfile --build-arg git_branch=`git name-rev --name-only HEAD` .
 
 debug:	FORCE
 	make ZT_DEBUG=1 one