Adds update option to plugin command

Fixes issues/2385 - helm install silently updates the plugin, if it pre-existed

cmd/helm/plugin.go

@@ -41,6 +41,7 @@ func newPluginCmd(out io.Writer) *cobra.Command {
 		newPluginInstallCmd(out),
 		newPluginListCmd(out),
 		newPluginRemoveCmd(out),
+		newPluginUpdateCmd(out),
 	)
 	return cmd
 }

cmd/helm/plugin_update.go

@@ -0,0 +1,109 @@
+/*
+Copyright 2017 The Kubernetes Authors All rights reserved.
+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 main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+
+	"k8s.io/helm/pkg/helm/helmpath"
+	"k8s.io/helm/pkg/plugin"
+	"k8s.io/helm/pkg/plugin/installer"
+
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+)
+
+type pluginUpdateCmd struct {
+	names []string
+	home  helmpath.Home
+	out   io.Writer
+}
+
+func newPluginUpdateCmd(out io.Writer) *cobra.Command {
+	pcmd := &pluginUpdateCmd{out: out}
+	cmd := &cobra.Command{
+		Use:   "update <plugin>...",
+		Short: "update one or more Helm plugins",
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			return pcmd.complete(args)
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return pcmd.run()
+		},
+	}
+	return cmd
+}
+
+func (pcmd *pluginUpdateCmd) complete(args []string) error {
+	if len(args) == 0 {
+		return errors.New("please provide plugin name to update")
+	}
+	pcmd.names = args
+	pcmd.home = settings.Home
+	return nil
+}
+
+func (pcmd *pluginUpdateCmd) run() error {
+	installer.Debug = settings.Debug
+	plugdirs := pluginDirs(pcmd.home)
+	debug("loading installed plugins from %s", plugdirs)
+	plugins, err := findPlugins(plugdirs)
+	if err != nil {
+		return err
+	}
+	for _, name := range pcmd.names {
+		if found := findPlugin(plugins, name); found != nil {
+			if err := updatePlugin(found, pcmd.home); err != nil {
+				fmt.Fprintf(pcmd.out, "Failed to update plugin %s, got error (%v)\n", name, err)
+			} else {
+				fmt.Fprintf(pcmd.out, "Updated plugin: %s\n", name)
+			}
+		} else {
+			fmt.Fprintf(pcmd.out, "Plugin: %s not found\n", name)
+		}
+	}
+	return nil
+}
+
+func updatePlugin(p *plugin.Plugin, home helmpath.Home) error {
+	exactLocation, err := filepath.EvalSymlinks(p.Dir)
+	if err != nil {
+		return err
+	}
+	absExactLocation, err := filepath.Abs(exactLocation)
+	if err != nil {
+		return err
+	}
+
+	i, err := installer.FindSource(absExactLocation, home)
+	if err != nil {
+		return err
+	}
+	if err := installer.Update(i); err != nil {
+		return err
+	}
+
+	debug("loading plugin from %s", i.Path())
+	updatedPlugin, err := plugin.LoadDir(i.Path())
+	if err != nil {
+		return err
+	}
+
+	return runHook(updatedPlugin, plugin.Update, home)
+}

pkg/plugin/hooks.go

@@ -21,6 +21,8 @@ const (
 	Install = "install"
 	// Delete is executed after the plugin is removed.
 	Delete = "delete"
+	// Update is executed after the plugin is removed.
+	Update = "update"
 )
 
 // Hooks is a map of events to commands.

pkg/plugin/installer/installer.go

@@ -36,6 +36,8 @@ type Installer interface {
 	Install() error
 	// Path is the directory of the installed plugin.
 	Path() string
+	// Update updates a plugin to $HELM_HOME.
+	Update() error
 }
 
 // Install installs a plugin to $HELM_HOME.
@@ -47,6 +49,15 @@ func Install(i Installer) error {
 	return i.Install()
 }
 
+// Update updates a plugin to $HELM_HOME.
+func Update(i Installer) error {
+	if _, pathErr := os.Stat(i.Path()); os.IsNotExist(pathErr) {
+		return errors.New("plugin does not exists")
+	}
+
+	return i.Update()
+}
+
 // NewForSource determines the correct Installer for the given source.
 func NewForSource(source, version string, home helmpath.Home) (Installer, error) {
 	// Check if source is a local directory
@@ -56,6 +67,15 @@ func NewForSource(source, version string, home helmpath.Home) (Installer, error)
 	return NewVCSInstaller(source, version, home)
 }
 
+// FindSource determines the correct Installer for the given source.
+func FindSource(location string, home helmpath.Home) (Installer, error) {
+	installer, err := existingVCSRepo(location, home)
+	if err != nil && err.Error() == "Cannot detect VCS" {
+		return installer, errors.New("cannot get information about plugin source")
+	}
+	return installer, err
+}
+
 // isLocalReference checks if the source exists on the filesystem.
 func isLocalReference(source string) bool {
 	_, err := os.Stat(source)

pkg/plugin/installer/local_installer.go

@@ -47,3 +47,9 @@ func (i *LocalInstaller) Install() error {
 	}
 	return i.link(src)
 }
+
+// Update updates a local repository
+func (i *LocalInstaller) Update() error {
+	debug("local repository is auto-updated")
+	return nil
+}

pkg/plugin/installer/vcs_installer.go

@@ -34,6 +34,18 @@ type VCSInstaller struct {
 	base
 }
 
+func existingVCSRepo(location string, home helmpath.Home) (Installer, error) {
+	repo, err := vcs.NewRepo("", location)
+	if err != nil {
+		return nil, err
+	}
+	i := &VCSInstaller{
+		Repo: repo,
+		base: newBase(repo.Remote(), home),
+	}
+	return i, err
+}
+
 // NewVCSInstaller creates a new VCSInstaller.
 func NewVCSInstaller(source, version string, home helmpath.Home) (*VCSInstaller, error) {
 	key, err := cache.Key(source)
@@ -77,6 +89,18 @@ func (i *VCSInstaller) Install() error {
 	return i.link(i.Repo.LocalPath())
 }
 
+// Update updates a remote repository
+func (i *VCSInstaller) Update() error {
+	debug("updating %s", i.Repo.Remote())
+	if err := i.Repo.Update(); err != nil {
+		return err
+	}
+	if !isPlugin(i.Repo.LocalPath()) {
+		return ErrMissingMetadata
+	}
+	return nil
+}
+
 func (i *VCSInstaller) solveVersion(repo vcs.Repo) (string, error) {
 	if i.Version == "" {
 		return "", nil