[WIP] K8s update and runtime package changes (#895)

* First commit: outline of K8s runtime package

* Added poller. Added auto-updater into default runtime

* Added build and updated Poller interface

* Added comments and NewRuntime that accepts Options

* DefaultPoller; Runtime options

* First commit to add Kubernetes cruft

* Add comments

* Add micro- prefix to K8s runtime service names

* Get rid of import cycles. Move K8s runtime into main runtime package

* Major refactoring: Poller replaced by Notifier

POller has been replaced by Notifier which returns a channel of events
that can be consumed and acted upon.

* Added runtime configuration options

* K8s runtime is now Kubernetes runtime in dedicated pkg. Naming kung-fu.

* Fix typo in command.

* Fixed typo

* Dont Delete service when runtime stops.

runtime.Stop stops services; no need to double-stop

* Track runtime services

* Parse Unix timestamps properly

* Added deployments into K8s client. Debug logging

runtime/options.go

@@ -4,8 +4,24 @@ import (
 	"io"
 )
 
+type Option func(o *Options)
+
+// Options configure runtime
+type Options struct {
+	// Notifier for updates
+	Notifier Notifier
+}
+
+// AutoUpdate enables micro auto-updates
+func WithNotifier(n Notifier) Option {
+	return func(o *Options) {
+		o.Notifier = n
+	}
+}
+
 type CreateOption func(o *CreateOptions)
 
+// CreateOptions configure runtime services
 type CreateOptions struct {
 	// command to execute including args
 	Command []string
@@ -25,7 +41,7 @@ func WithCommand(c string, args ...string) CreateOption {
 	}
 }
 
-// WithEnv sets the created service env
+// WithEnv sets the created service environment
 func WithEnv(env []string) CreateOption {
 	return func(o *CreateOptions) {
 		o.Env = env