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

internal/controller/api.go

@@ -98,6 +98,9 @@ func (controller *Controller) initAPI() *gin.Engine {
 	v1.GET("/workers", func(c *gin.Context) {
 		controller.listWorkers(c).Respond(c)
 	})
+	v1.GET("/workers/:name/port-forward", func(c *gin.Context) {
+		controller.portForwardWorker(c).Respond(c)
+	})
 	v1.DELETE("/workers/:name", func(c *gin.Context) {
 		controller.deleteWorker(c).Respond(c)
 	})

internal/controller/api_vms_portforward.go

@@ -47,23 +47,34 @@ func (controller *Controller) portForwardVM(ctx *gin.Context) responder.Responde
 		return responderImpl
 	}
 
+	// Commence port-forwarding
+	return controller.portForward(ctx, vm.Worker, vm.UID, uint32(port))
+}
+
+func (controller *Controller) portForward(
+	ctx *gin.Context,
+	workerName string,
+	vmUID string,
+	port uint32,
+) responder.Responder {
 	// Request and wait for a connection with a worker
 	session := uuid.New().String()
 	boomerangConnCh, cancel := controller.proxy.Request(ctx, session)
 	defer cancel()
 
 	// send request to worker to initiate port-forwarding connection back to us
-	err = controller.workerNotifier.Notify(ctx, vm.Worker, &rpc.WatchInstruction{
+	err := controller.workerNotifier.Notify(ctx, workerName, &rpc.WatchInstruction{
 		Action: &rpc.WatchInstruction_PortForwardAction{
 			PortForwardAction: &rpc.WatchInstruction_PortForward{
 				Session: session,
-				VmUid:   vm.UID,
-				VmPort:  uint32(port),
+				VmUid:   vmUID,
+				Port:    port,
 			},
 		},
 	})
 	if err != nil {
-		controller.logger.Warnf("failed to request port-forwarding from the worker %s: %v", vm.Worker, err)
+		controller.logger.Warnf("failed to request port-forwarding from the worker %s: %v",
+			workerName, err)
 
 		return responder.Code(http.StatusServiceUnavailable)
 	}

internal/controller/api_workers_portforward.go

@@ -0,0 +1,44 @@
+package controller
+
+import (
+	storepkg "github.com/cirruslabs/orchard/internal/controller/store"
+	"github.com/cirruslabs/orchard/internal/responder"
+	v1 "github.com/cirruslabs/orchard/pkg/resource/v1"
+	"github.com/gin-gonic/gin"
+	"net/http"
+	"strconv"
+)
+
+func (controller *Controller) portForwardWorker(ctx *gin.Context) responder.Responder {
+	if responder := controller.authorize(ctx, v1.ServiceAccountRoleAdminWrite); responder != nil {
+		return responder
+	}
+
+	// Retrieve and parse path and query parameters
+	name := ctx.Param("name")
+
+	portRaw := ctx.Query("port")
+	port, err := strconv.ParseUint(portRaw, 10, 16)
+	if err != nil {
+		return responder.Code(http.StatusBadRequest)
+	}
+	if port < 1 || port > 65535 {
+		return responder.Code(http.StatusBadRequest)
+	}
+
+	var worker *v1.Worker
+
+	if responder := controller.storeView(func(txn storepkg.Transaction) responder.Responder {
+		worker, err = txn.GetWorker(name)
+		if err != nil {
+			return responder.Error(err)
+		}
+
+		return nil
+	}); responder != nil {
+		return responder
+	}
+
+	// Commence port-forwarding
+	return controller.portForward(ctx, worker.Name, "", uint32(port))
+}