Basic support for kubectl plugins

pkg/kubectl/plugins/plugins.go

@@ -0,0 +1,58 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package plugins
+
+import "fmt"
+
+// Plugin is the representation of a CLI extension (plugin).
+type Plugin struct {
+	Description
+	Source
+	Context RunningContext `json:"-"`
+}
+
+// PluginDescription holds everything needed to register a
+// plugin as a command. Usually comes from a descriptor file.
+type Description struct {
+	Name      string `json:"name"`
+	ShortDesc string `json:"shortDesc"`
+	LongDesc  string `json:"longDesc,omitempty"`
+	Example   string `json:"example,omitempty"`
+	Command   string `json:"command"`
+}
+
+// PluginSource holds the location of a given plugin in the filesystem.
+type Source struct {
+	Dir            string `json:"-"`
+	DescriptorName string `json:"-"`
+}
+
+var IncompleteError = fmt.Errorf("incomplete plugin descriptor: name, shortDesc and command fields are required")
+
+func (p Plugin) Validate() error {
+	if len(p.Name) == 0 || len(p.ShortDesc) == 0 || len(p.Command) == 0 {
+		return IncompleteError
+	}
+	return nil
+}
+
+func (p Plugin) IsValid() bool {
+	return p.Validate() == nil
+}
+
+// Plugins is a list of plugins.
+type Plugins []*Plugin