[release-v1.15] Add plugin install command (#524)

* Add plugin install command

* Split into functions and cleanup code

* Fix formatting of desc

* Add plugin remove and update flag

* Update pkg/kn/commands/plugin/install.go

Co-authored-by: Roland Huß <[email protected]>

* Update pkg/kn/commands/plugin/remove.go

Co-authored-by: Roland Huß <[email protected]>

* Update pkg/kn/commands/plugin/remove.go

Co-authored-by: Roland Huß <[email protected]>

* Update pkg/kn/commands/plugin/remove.go

Co-authored-by: Roland Huß <[email protected]>

* Update pkg/kn/commands/plugin/remove.go

Co-authored-by: Roland Huß <[email protected]>

* Apply suggestions from code review

Co-authored-by: Roland Huß <[email protected]>

* Remove misleading alias cmd

---------

Co-authored-by: David Simansky <[email protected]>
Co-authored-by: Roland Huß <[email protected]>

pkg/kn/commands/plugin/install.go

@@ -0,0 +1,145 @@
+// Copyright © 2024 The Knative 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 plugin
+
+import (
+	"errors"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/spf13/cobra"
+
+	"knative.dev/client/pkg/kn/commands"
+	"knative.dev/client/pkg/kn/config"
+)
+
+var updateFlag bool
+
+// NewPluginInstallCommand creates a new `kn plugin install` command
+func NewPluginInstallCommand(p *commands.KnParams) *cobra.Command {
+
+	var localPath string
+	cmd := &cobra.Command{
+		Use:   "install",
+		Short: "Install a plugin from URL or local file",
+		Long: `Install a plugin by downloading it from a URL or the local filesystem.
+
+Pick up a plugin from a URL or a local path and copy it to ${KN_CONFIG_DIR}/kn/plugins.
+
+Current: ` + config.GlobalConfig.PluginsDir(),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(args) != 1 {
+				if localPath == "" {
+					return errors.New("'kn plugin install' requires the URL as argument or local file specified via '-f'")
+				}
+				println("Copying plugin from " + localPath)
+				// Local plugin file to copy
+				return fetchLocal(localPath)
+			}
+			println("Downloading from " + args[0])
+			// Download from provided external URL and copy to plugins dir
+			return fetchFromURL(args[0])
+		},
+	}
+	cmd.Flags().StringVarP(&localPath, "file", "f", "", "Path to install plugin from local filesystem")
+	cmd.Flags().BoolVarP(&updateFlag, "update", "u", false, "Update installed plugin")
+	return cmd
+}
+
+func parseFilePath(src, separator string) string {
+	segments := strings.Split(src, separator)
+	return filepath.Join(config.GlobalConfig.PluginsDir(), segments[len(segments)-1])
+}
+
+func fetchLocal(localPath string) error {
+	localFile, err := os.Open(localPath)
+	if err != nil {
+		return err
+	}
+	fileName := parseFilePath(localPath, string(os.PathSeparator))
+
+	if err := updatePluginCheck(fileName); err != nil {
+		return err
+	}
+
+	dest, err := os.Create(fileName)
+	if err != nil {
+		return err
+	}
+	return installPlugin(fileName, dest, localFile)
+}
+
+func fetchFromURL(externalUrl string) error {
+	// Build fileName from fullPath
+	fileURL, err := url.Parse(externalUrl)
+	if err != nil {
+		return err
+	}
+	path := fileURL.Path
+	// Assuming URL, hence forward-slash separator
+	fileName := parseFilePath(path, "/")
+
+	client := &http.Client{
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+
+	// Download file
+	resp, err := client.Get(fileURL.String())
+	if err != nil {
+		println(err)
+	}
+	defer resp.Body.Close()
+
+	if err := updatePluginCheck(fileName); err != nil {
+		return err
+	}
+
+	file, err := os.Create(fileName)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	return installPlugin(fileName, file, resp.Body)
+}
+
+func updatePluginCheck(path string) error {
+	_, err := os.Stat(path)
+	if !os.IsNotExist(err) {
+		if !updateFlag {
+			return errors.New("plugin already exists, please use `--update` flag to replace it at '" + path + "'")
+		}
+	}
+	return nil
+}
+
+func installPlugin(fileName string, dst io.Writer, src io.Reader) error {
+	_, err := io.Copy(dst, src)
+	if err != nil {
+		return err
+	}
+	err = os.Chmod(fileName, os.FileMode(0755))
+	if err != nil {
+		return err
+	}
+	println("Plugin installed to '" + fileName + "'")
+	return nil
+}

pkg/kn/commands/plugin/plugin.go

@@ -31,7 +31,8 @@ Plugins provide extended functionality that is not part of the core kn command-l
 Please refer to the documentation and examples for more information about how to write your own plugins.`,
 	}
 
+	pluginCmd.AddCommand(NewPluginInstallCommand(p))
+	pluginCmd.AddCommand(NewPluginRemoveCommand(p))
 	pluginCmd.AddCommand(NewPluginListCommand(p))
-
 	return pluginCmd
 }

pkg/kn/commands/plugin/remove.go

@@ -0,0 +1,52 @@
+// Copyright © 2024 The Knative 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 plugin
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+
+	"knative.dev/client/pkg/kn/commands"
+	"knative.dev/client/pkg/kn/config"
+)
+
+// NewPluginRemoveCommand creates a new `kn plugin remove` command
+func NewPluginRemoveCommand(p *commands.KnParams) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "remove",
+		Short: "remove a plugin",
+		Long: `Remove a plugin.
+
+Plugin is removed from ${KN_CONFIG_DIR}/kn/plugins.
+
+Current: ` + config.GlobalConfig.PluginsDir(),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(args) != 1 {
+				return errors.New("'kn plugin remove' requires plugin name")
+			}
+			name := args[0]
+			filename := filepath.Join(config.GlobalConfig.PluginsDir(), name)
+			if _, err := os.Stat(filename); os.IsNotExist(err) {
+				return errors.New("plugin '" + name + "' does not exist")
+			}
+			println("Removed plugin '" + filename + "'")
+			return os.Remove(filename)
+		},
+	}
+	return cmd
+}