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/timetrigger/create.go

@@ -18,6 +18,7 @@ package timetrigger
 
 import (
 	"fmt"
+	"github.com/fission/fission/pkg/fission-cli/cmd"
 	"time"
 
 	"github.com/pkg/errors"
@@ -35,19 +36,12 @@ import (
 )
 
 type CreateSubCommand struct {
-	client  *client.Client
+	cmd.CommandActioner
 	trigger *fv1.TimeTrigger
 }
 
 func Create(input cli.Input) error {
-	c, err := util.GetServer(input)
-	if err != nil {
-		return err
-	}
-	opts := CreateSubCommand{
-		client: c,
-	}
-	return opts.do(input)
+	return (&CreateSubCommand{}).do(input)
 }
 
 func (opts *CreateSubCommand) do(input cli.Input) error {
@@ -126,14 +120,14 @@ func (opts *CreateSubCommand) run(input cli.Input) error {
 		return nil
 	}
 
-	_, err := opts.client.TimeTriggerCreate(opts.trigger)
+	_, err := opts.Client().V1().TimeTrigger().Create(opts.trigger)
 	if err != nil {
 		return errors.Wrap(err, "error creating Time trigger")
 	}
 
 	fmt.Printf("trigger '%v' created\n", opts.trigger.Metadata.Name)
 
-	t, err := getAPITimeInfo(opts.client)
+	t, err := getAPITimeInfo(opts.Client())
 	if err != nil {
 		return err
 	}
@@ -146,8 +140,8 @@ func (opts *CreateSubCommand) run(input cli.Input) error {
 	return nil
 }
 
-func getAPITimeInfo(client *client.Client) (time.Time, error) {
-	serverInfo, err := client.ServerInfo()
+func getAPITimeInfo(client client.Interface) (time.Time, error) {
+	serverInfo, err := client.V1().Misc().ServerInfo()
 	if err != nil {
 		return time.Time{}, errors.Errorf("Error syncing server time information: %v", err)
 	}