Introduce "orchard {port-forward, vnc} worker WORKER_NAME" (#140)

* Fix potential NPE in Client.wsRequest()

* Introduce "orchard {port-forward, vnc} worker WORKER_NAME"

* portspec.go: simplify logic and respect [LOCAL_PORT]:REMOTE_PORT format

pkg/client/client.go

@@ -271,10 +271,10 @@ func (client *Client) wsRequest(
 	if err != nil {
 		if resp != nil {
 			_ = resp.Body.Close()
-		}
 
-		if resp.StatusCode == http.StatusNotFound {
-			err = fmt.Errorf("%w (are you sure this VM exists on the controller?)", err)
+			if resp.StatusCode == http.StatusNotFound {
+				err = fmt.Errorf("%w (are you sure this VM exists on the controller?)", err)
+			}
 		}
 
 		return nil, err

pkg/client/workers.go

@@ -4,8 +4,10 @@ import (
 	"context"
 	"fmt"
 	"github.com/cirruslabs/orchard/pkg/resource/v1"
+	"net"
 	"net/http"
 	"net/url"
+	"strconv"
 )
 
 type WorkersService struct {
@@ -65,3 +67,14 @@ func (service *WorkersService) Delete(ctx context.Context, name string) error {
 
 	return nil
 }
+
+func (service *WorkersService) PortForward(
+	ctx context.Context,
+	name string,
+	port uint16,
+) (net.Conn, error) {
+	return service.client.wsRequest(ctx, fmt.Sprintf("workers/%s/port-forward", url.PathEscape(name)),
+		map[string]string{
+			"port": strconv.FormatUint(uint64(port), 10),
+		})
+}