(And with existing Spring Cloud projects.) Uses a maven plugin to
build the image. It can be pushed manually, or else using
-Ddocker.image.prefix=<path_to_repo>. Removes some of the hard-coded
host names and stuff that came with the old version.
Standard channel interface types of Sink, Source, Processor
are provided, but user can create others with @Input and
@Output MessageChannel methods.
To get the declared channels in an app you can use the
@ModuleChannels qualifier to inject the interface, e.g.
@ModuleChannels(Cafe.class) injects the channels defined
in the Cafe.
