Building docker-ce src.rpm

I have a CentOS 7.1 system that I cannot update to 7.5+, but I would love to build the latest docker-ce (18.06.1) on it. Typically one might start with a src.rpm, but I’m finding that the whole idea of source being “contained” in the src.rpm isn’t the practice. There are tons of git clones during the build process… It also looks like the src.rpm is expected to be built within a container. Anyways, I have found this to be an overwhelming task, but can’t find any real dependency in the docker-ce code that it shouldn’t compile with CentOS 7.1.

Is there an archive of docker-ce builds (rpm) from the CentOS 7.1 era somewhere? Is there an archive of the containers used to build the rpm(s) somewhere?

Any help offered will be greatly appreciated!