Add controller API client interface (#1467)

This PR adds an interface for controller API client, it allows us to
implement mock API client for unit testing with ease and we are
able to generate spec file without accessing the real Fission server.

pkg/fission-cli/cmd/package/get.go

@@ -24,11 +24,10 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	fv1 "github.com/fission/fission/pkg/apis/fission.io/v1"
-	"github.com/fission/fission/pkg/controller/client"
 	"github.com/fission/fission/pkg/fission-cli/cliwrapper/cli"
+	"github.com/fission/fission/pkg/fission-cli/cmd"
 	pkgutil "github.com/fission/fission/pkg/fission-cli/cmd/package/util"
 	flagkey "github.com/fission/fission/pkg/fission-cli/flag/key"
-	"github.com/fission/fission/pkg/fission-cli/util"
 )
 
 const (
@@ -37,7 +36,7 @@ const (
 )
 
 type GetSubCommand struct {
-	client      *client.Client
+	cmd.CommandActioner
 	name        string
 	namespace   string
 	output      string
@@ -45,27 +44,11 @@ type GetSubCommand struct {
 }
 
 func GetSrc(input cli.Input) error {
-	c, err := util.GetServer(input)
-	if err != nil {
-		return err
-	}
-	opts := GetSubCommand{
-		client:      c,
-		archiveType: sourceArchive,
-	}
-	return opts.do(input)
+	return (&GetSubCommand{}).do(input)
 }
 
 func GetDeploy(input cli.Input) error {
-	c, err := util.GetServer(input)
-	if err != nil {
-		return err
-	}
-	opts := GetSubCommand{
-		client:      c,
-		archiveType: deployArchive,
-	}
-	return opts.do(input)
+	return (&GetSubCommand{}).do(input)
 }
 
 func (opts *GetSubCommand) do(input cli.Input) error {
@@ -84,7 +67,7 @@ func (opts *GetSubCommand) complete(input cli.Input) error {
 }
 
 func (opts *GetSubCommand) run(input cli.Input) error {
-	pkg, err := opts.client.PackageGet(&metav1.ObjectMeta{
+	pkg, err := opts.Client().V1().Package().Get(&metav1.ObjectMeta{
 		Namespace: opts.namespace,
 		Name:      opts.name,
 	})
@@ -101,7 +84,7 @@ func (opts *GetSubCommand) run(input cli.Input) error {
 	if pkg.Spec.Deployment.Type == fv1.ArchiveTypeLiteral {
 		reader = bytes.NewReader(archive.Literal)
 	} else if pkg.Spec.Deployment.Type == fv1.ArchiveTypeUrl {
-		readCloser, err := pkgutil.DownloadStoragesvcURL(opts.client, archive.URL)
+		readCloser, err := pkgutil.DownloadStoragesvcURL(opts.Client(), archive.URL)
 		if err != nil {
 			return err
 		}