[WIP] Micro Runtime (#947)

* Add Get() and GetOptions.

* Removed watcher. Outline of client. YAML templates

* Added default service and deployment templates and types

* Added API tests and cleaned up errors.

* Small refactoring. Template package is no more.

* Ripped out existing code in preparation to small rework

* Reshuffled the source code to make it organized better

* Create service and deployment in kubernetes runtime

* Major cleanup and refactoring of Kubernetes runtime

* Service now handles low level K8s API calls across both K8s deployment
an service API objects
* Runtime has a task queue that serves for queueing runtime action
requests
* General refactoring

* No need for Lock in k8s service

* Added kubernetes runtime env var to default deployment

* Enable running different versions of the same service

* Can't delete services through labels

* Proto cruft. Added runtime.CreateOptions implementation in proto

* Removed proxy service from default env variables

* Make service name mandatory param to Get method

* Get Delete changes from https://github.com/micro/go-micro/pull/945

* Replaced template files with global variables

* Validate service names before sending K8s API request

* Refactored Kubernetes API client. Fixed typos.

* Added client.Resource to make API resources more explicit in code

runtime/kubernetes/service.go

@@ -0,0 +1,106 @@
+package kubernetes
+
+import (
+	"strings"
+
+	"github.com/micro/go-micro/runtime"
+	"github.com/micro/go-micro/runtime/kubernetes/client"
+	"github.com/micro/go-micro/util/log"
+)
+
+type service struct {
+	// service to manage
+	*runtime.Service
+	// Kubernetes service
+	kservice *client.Service
+	// Kubernetes deployment
+	kdeploy *client.Deployment
+}
+
+func newService(s *runtime.Service, c runtime.CreateOptions) *service {
+	kservice := client.DefaultService(s.Name, s.Version)
+	kdeploy := client.DefaultDeployment(s.Name, s.Version)
+
+	env := make([]client.EnvVar, 0, len(c.Env))
+	for _, evar := range c.Env {
+		evarPair := strings.Split(evar, "=")
+		env = append(env, client.EnvVar{Name: evarPair[0], Value: evarPair[1]})
+	}
+
+	// TODO: should we append instead of overriding?
+	// if environment has been supplied update deployment
+	if len(env) > 0 {
+		kdeploy.Spec.Template.PodSpec.Containers[0].Env = env
+	}
+
+	// if Command has been supplied override the default command
+	if len(c.Command) > 0 {
+		kdeploy.Spec.Template.PodSpec.Containers[0].Command = c.Command
+	}
+
+	return &service{
+		Service:  s,
+		kservice: kservice,
+		kdeploy:  kdeploy,
+	}
+}
+
+func deploymentResource(d *client.Deployment) *client.Resource {
+	return &client.Resource{
+		Name:  d.Metadata.Name,
+		Kind:  "deployment",
+		Value: d,
+	}
+}
+
+func serviceResource(s *client.Service) *client.Resource {
+	return &client.Resource{
+		Name:  s.Metadata.Name,
+		Kind:  "service",
+		Value: s,
+	}
+}
+
+// Start starts the Kubernetes service. It creates new kubernetes deployment and service API objects
+func (s *service) Start(k client.Kubernetes) error {
+	// create deployment first; if we fail, we dont create service
+	if err := k.Create(deploymentResource(s.kdeploy)); err != nil {
+		log.Debugf("Runtime failed to create deployment: %v", err)
+		return err
+	}
+	// create service now that the deployment has been created
+	if err := k.Create(serviceResource(s.kservice)); err != nil {
+		log.Debugf("Runtime failed to create service: %v", err)
+		return err
+	}
+
+	return nil
+}
+
+func (s *service) Stop(k client.Kubernetes) error {
+	// first attempt to delete service
+	if err := k.Delete(serviceResource(s.kservice)); err != nil {
+		log.Debugf("Runtime failed to delete service: %v", err)
+		return err
+	}
+	// delete deployment once the service has been deleted
+	if err := k.Delete(deploymentResource(s.kdeploy)); err != nil {
+		log.Debugf("Runtime failed to delete deployment: %v", err)
+		return err
+	}
+
+	return nil
+}
+
+func (s *service) Update(k client.Kubernetes) error {
+	if err := k.Update(deploymentResource(s.kdeploy)); err != nil {
+		log.Debugf("Runtime failed to update deployment: %v", err)
+		return err
+	}
+	if err := k.Update(serviceResource(s.kservice)); err != nil {
+		log.Debugf("Runtime failed to update service: %v", err)
+		return err
+	}
+
+	return nil
+}