FWIW the first two are solved by git without any service. Git can set up a post receive hook, which could do the triggering. SSH key auth is a thing as part o

FWIW the first two are solved by git without any service. Git can set up a post receive hook, which could do the triggering. SSH key auth is a thing as part of Git+SSH. Sure I couldn't set this with e.g. GitLab without them supporting GitLab, but if I'm self-hosting a git service, this seems like a fine solution.