Collect all rpm dependencies to deploy a project - deployment

Question

I need to deploy a software project (packaged as an rpm) from a developer machine into a server. I'm using Fedora 23, along with the dnf package manager. I have to collect all dependencies of my rpm before I deploy to the server. The server can't be connected to the internet due to internal regulation (But I can ssh onto it). Running repository mirrors, etc. is not an option. I'm afraid I just have to collect all dependencies on the developer machine, scp (or ansible) them to the server and install them on the server.
I hoped that --installroot option in dnf could be of much help, as I could retrieve all rpms that would get installed into what dnf thinks is an empty system. This however doesn't work.
mkdir foo && sudo dnf install --installroot=$PWD/foo golang
gives an error:
Failed to synchronize cache for repo 'fedora'
Why does this fail? What are my options?
I'd like to see an elegant and robust solution. I'd prefer not to install anything on the server (I'd be most happy to do a single scp followed by one or two commands over ssh). A combination of rpm + yum/dnf magic would be great, but other solutions, including apt + deb are also of interest. I'd prefer not to use docker, and I'm strongly against running any additional infrastructure (docker registry, rpm mirror, etc.)

Answer 1

Here is a (ad hoc, lightly tested) script (assuming you have an already installed rpm system) to generate the list of all the rpm package names needed to install a given package (the script assumes goal="bash", edit to taste).
Feed the output names to dnf/yum to install.
#!/bin/sh
goal=bash
deps=$(rpm -q --qf '[%{REQUIRENAME}\n]' $goal | egrep -v '^(rpmlib|rtld|config|/)')
goals=
while true; do
subs=$(rpm -q --qf '%{NAME}\n' --whatprovides $deps | sort -u | tr '\n' ' ')
if [ ."$subs" = ."$goals" ]; then
echo "--- packages needed"
echo "$goals" | tr ' ' '\n'
exit 0
fi
goals=$(echo $goals $subs | tr ' ' '\n' | sort -u | tr '\n' ' ')
for sub in $subs; do
subdeps=$(rpm -q --qf '[%{REQUIRENAME}\n]' $sub | egrep -v '^(rpmlib|rtld|config|/)')
deps=$(echo $deps $subdeps | sort -u)
done
done