return error earlier when no nodes available (#617)

Author: yuyang0

cluster/calcium/create.go

@@ -103,6 +103,9 @@ func (c *Calcium) doCreateWorkloads(ctx context.Context, opts *types.DeployOptio
 					}
 				}()
 				return c.withNodesPodLocked(ctx, opts.NodeFilter, func(ctx context.Context, nodeMap map[string]*types.Node) (err error) {
+					if len(nodeMap) == 0 {
+						return types.ErrEmptyNodeMap
+					}
 					nodenames := []string{}
 					nodes := []*types.Node{}
 					for nodename, node := range nodeMap {

types/errors.go

@@ -81,6 +81,7 @@ var (
 	ErrInvalidGitURL               = errors.New("invalid git url format")
 	ErrInvalidVolumeBind           = errors.New("invalid volume bind value")
 	ErrEmptyNodeName               = errors.New("node name is empty")
+	ErrEmptyNodeMap                = errors.New("node map is empty")
 	ErrEmptyAppName                = errors.New("app name is empty")
 	ErrEmptyPodName                = errors.New("pod name is empty")
 	ErrEmptyImage                  = errors.New("image is empty")