This is a major refactor of the destination service. The goals of this refactor are to simplify the code for improved maintainability. In particular:
* Remove the "resolver" interfaces. These were a holdover from when our decision tree was more complex about how to handle different kinds of authorities. The current implementation only accepts fully qualified kubernetes service names and thus this was an unnecessary level of indirection.
* Moved the endpoints and profile watchers into their own package for a more clear separation of concerns. These watchers deal only in Kubernetes primitives and are agnostic to how they are used. This allows a cleaner layering when we use them from our gRPC service.
* Renamed the "listener" types to "translator" to make it more clear that the function of these structs is to translate kubernetes updates from the watcher to gRPC messages.
Signed-off-by: Alex Leong <alex@buoyant.io>
Up until now, the proxy-api controller service has been the sole service
that the proxy communicates with, implementing the majoriry of the API
defined in the `linkerd2-proxy-api` repo. But this is about to change:
linkerd/linkerd2-proxy-api#25 introduces a new Identity service; and
this service must be served outside of the existing proxy-api service
in the linkerd-controller deployment (so that it may run under a
distinct service account).
With this change, the "proxy-api" name becomes less descriptive. It's no
longer "the service that serves the API for the proxy," it's "the
service that serves the Destination API to the proxy." Therefore, it
seems best to bite the bullet and rename this to be the "destination"
service (i.e. because it only serves the
`io.linkerd.proxy.destination.Destination` service).
Co-authored-by: Kevin Lingerfelt <kl@buoyant.io>
Signed-off-by: Kevin Lingerfelt <kl@buoyant.io>
Alex Leong
Andrew Seigner
Kevin Lingerfelt
Oliver Gould