tridentctl plugin support (#1697)

cli/cmd/plugins.go

@@ -0,0 +1,95 @@
+package cmd
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/spf13/cobra"
+)
+
+const (
+	tridentctlPrefix = "tridentctl-"
+	execMask         = 0o111
+	pluginPathEnvVar = "TRIDENTCTL_PLUGIN_PATH"
+)
+
+func init() {
+	// search PATH for all binaries starting with "tridentctl-"
+	binaries := findBinaries(tridentctlPrefix)
+
+	plugins := make([]*cobra.Command, 0, len(binaries))
+	for _, binary := range binaries {
+		pluginName := strings.TrimPrefix(filepath.Base(binary), tridentctlPrefix)
+		pluginCmd := &cobra.Command{
+			Use:                pluginName,
+			Short:              "Run the " + pluginName + " plugin",
+			GroupID:            "plugins",
+			DisableFlagParsing: true,
+			Run: func(cmd *cobra.Command, args []string) {
+				pluginCommand := binary
+
+				os.Setenv("TRIDENTCTL_PLUGIN_INVOCATION", "true")
+
+				execCmd := exec.Command(pluginCommand, args...)
+				execCmd.Stdin = os.Stdin
+				execCmd.Stdout = os.Stdout
+				execCmd.Stderr = os.Stderr
+
+				err := execCmd.Run()
+				if err != nil {
+					fmt.Printf("Error executing plugin command: %v\n", err)
+				}
+			},
+		}
+		plugins = append(plugins, pluginCmd)
+
+	}
+
+	if len(plugins) == 0 {
+		return
+	}
+
+	pluginGroup := cobra.Group{
+		ID:    "plugins",
+		Title: "Plugins",
+	}
+
+	RootCmd.AddGroup(&pluginGroup)
+	for _, pluginCmd := range plugins {
+		RootCmd.AddCommand(pluginCmd)
+	}
+}
+
+func findBinaries(prefix string) []string {
+	var binaries []string
+	path := os.Getenv(pluginPathEnvVar)
+	if path == "" {
+		path = os.Getenv("PATH")
+	}
+
+	for _, dir := range strings.Split(path, ":") {
+		files, err := filepath.Glob(filepath.Join(dir, prefix+"*"))
+		if err != nil {
+			log.Println(err)
+			continue
+		}
+		for _, file := range files {
+			if isExecutable(file) {
+				binaries = append(binaries, file)
+			}
+		}
+	}
+	return binaries
+}
+
+func isExecutable(file string) bool {
+	info, err := os.Stat(file)
+	if err != nil {
+		return false
+	}
+	return info.Mode().IsRegular() && info.Mode()&execMask != 0
+}