The functionality provided on this repo was finally implemented on Systemd with "systemd-time-wait-sync"
Proper time-sync.target support for systemd-timesyncd
This package essentially just works around systemd/systemd#5097
systemd.special(7) tells us that "All services where correct time is essential should be ordered after [time-sync.target]". However, systemd-timesyncd allows time-sync.target to be reached before timesyncd has actually synchronized the time. This is because it sends READY=1 as soon as the daemon has initialized, rather that waiting until it has successfully synchronized to an NTP server.
It would be trivial to patch timesyncd to wait, but that would introduce some other problems.
So, I'm introducing systemd-timesyncd-wait. It is a service that listens for messages from systemd-timesyncd, and block until it sees a message indicating that systemd-timesyncd has synchronized the time.
go > 1.4
make
Clone the repo and execute:
make && make install