Installer is a standard interface for objects which can "install" themselves an engine by registering handlers. This can be used as an entrypoint for external plugins etc. Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes) Upstream-commit: 9422451ac3f541a17daba0d5f6dc8b40a6edc9e9 Component: engine