Ask HN: Source control with micro services

How are you handling source control with many micro services? Given that they become many quickly, are you creating separate repositories for each service, or a single repository for all, or grouping them or ??

Question comes up as we have built up quite a little pile of services and grouped them initially as it seemed easier to manage but as we get more it actually seems like we should have just one repository per service, making isolation explicit even in source control.