VNet in Connect: Send notification about bg item if not already enabled (gravitational#44219)

* Make serviceStatus public

* Print to stdout when VNet is ready

* Use executable name instead of saying "current executable"

This error bubbles up to the UI in Connect. In that context, "the current
executable" is ambiguous.

* Send notification about bg item if not already enabled

* Adjust notification copy

Co-authored-by: Grzegorz Zdunek <gzdunek@users.noreply.github.com>

---------

Co-authored-by: Grzegorz Zdunek <gzdunek@users.noreply.github.com>

Author: ravicious

gen/proto/go/teleport/lib/teleterm/vnet/v1/vnet_service.pb.go

@@ -0,0 +1,61 @@
+// Teleport
+// Copyright (C) 2024 Gravitational, Inc.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+//go:build vnetdaemon
+// +build vnetdaemon
+
+package vnet
+
+import (
+	"context"
+	"os"
+
+	"github.com/gravitational/trace"
+
+	api "github.com/gravitational/teleport/gen/proto/go/teleport/lib/teleterm/vnet/v1"
+	"github.com/gravitational/teleport/lib/vnet"
+	vnetdaemon "github.com/gravitational/teleport/lib/vnet/daemon"
+)
+
+func (s *Service) GetBackgroundItemStatus(ctx context.Context, req *api.GetBackgroundItemStatusRequest) (*api.GetBackgroundItemStatusResponse, error) {
+	if os.Getenv(vnet.EnvFeatureFlag) != "yes" {
+		return nil, trace.NotImplemented("tsh was built with VNet daemon support, but the feature flag is not enabled")
+	}
+
+	status, err := vnetdaemon.DaemonStatus()
+	if err != nil {
+		return nil, trace.Wrap(err)
+	}
+
+	return &api.GetBackgroundItemStatusResponse{
+		Status: backgroundItemStatusFromServiceStatus(status),
+	}, nil
+}
+
+func backgroundItemStatusFromServiceStatus(status vnetdaemon.ServiceStatus) api.BackgroundItemStatus {
+	switch status {
+	case vnetdaemon.ServiceStatusNotRegistered:
+		return api.BackgroundItemStatus_BACKGROUND_ITEM_STATUS_NOT_REGISTERED
+	case vnetdaemon.ServiceStatusEnabled:
+		return api.BackgroundItemStatus_BACKGROUND_ITEM_STATUS_ENABLED
+	case vnetdaemon.ServiceStatusRequiresApproval:
+		return api.BackgroundItemStatus_BACKGROUND_ITEM_STATUS_REQUIRES_APPROVAL
+	case vnetdaemon.ServiceStatusNotFound:
+		return api.BackgroundItemStatus_BACKGROUND_ITEM_STATUS_NOT_FOUND
+	default:
+		return api.BackgroundItemStatus_BACKGROUND_ITEM_STATUS_UNSPECIFIED
+	}
+}