Have you looked at Drone (https://github.com/drone/drone https://github.com/drone/drone)? They push their hosted service pretty hard but you can also self-host

Have you looked at Drone (https://github.com/drone/drone https://github.com/drone/drone)? They push their hosted service pretty hard but you can also self-host it (I currently am). I think it covers most of your needs except for #3. I haven't seen that done but that doesn't mean it isn't possible...