Test plugins from rootCommand

cmd/root.go

@@ -21,7 +21,7 @@ const defaultPluginDir = "_plugins/bin"
 
 // NewRootCmd creates the root `airshipctl` command. All other commands are
 // subcommands branching from this one
-func NewRootCmd(out io.Writer, args []string) (*cobra.Command, error) {
+func NewRootCmd(out io.Writer, pluginDir string, args []string) (*cobra.Command, error) {
 	rootCmd := &cobra.Command{
 		Use:   "airshipctl",
 		Short: "airshipctl is a unified entrypoint to various airship components",
@@ -33,14 +33,19 @@ func NewRootCmd(out io.Writer, args []string) (*cobra.Command, error) {
 
 	rootCmd.AddCommand(NewVersionCommand(out))
 
-	if _, err := os.Stat(defaultPluginDir); err == nil {
-		pluginFiles, err := util.ReadDir(defaultPluginDir)
+	if _, err := os.Stat(pluginDir); err == nil {
+		pluginFiles, err := util.ReadDir(pluginDir)
 		if err != nil {
 			return nil, errors.New("could not read plugins: " + err.Error())
 		}
 		for _, pluginFile := range pluginFiles {
-			pathToPlugin := filepath.Join(defaultPluginDir, pluginFile.Name())
-			rootCmd.AddCommand(plugin.CreateCommandFromPlugin(pathToPlugin, out, args))
+			pathToPlugin := filepath.Join(pluginDir, pluginFile.Name())
+			newCommand, err := plugin.CreateCommandFromPlugin(pathToPlugin, out, args)
+			if err != nil {
+				log.Debugf("Could not load plugin from %s: %s\n", pathToPlugin, err.Error())
+			} else {
+				rootCmd.AddCommand(newCommand)
+			}
 		}
 	}
 
@@ -51,7 +56,7 @@ func NewRootCmd(out io.Writer, args []string) (*cobra.Command, error) {
 
 // Execute runs the base airshipctl command
 func Execute(out io.Writer) {
-	rootCmd, err := NewRootCmd(out, os.Args[1:])
+	rootCmd, err := NewRootCmd(out, defaultPluginDir, os.Args[1:])
 	osExitIfError(out, err)
 	osExitIfError(out, rootCmd.Execute())
 }

internal/test/utilities.go

@@ -42,7 +42,7 @@ func executeCmd(t *testing.T, command string) []byte {
 	var actual bytes.Buffer
 	// TODO(howell): switch to shellwords (or similar)
 	args := strings.Fields(command)
-	rootCmd, err := cmd.NewRootCmd(&actual, args)
+	rootCmd, err := cmd.NewRootCmd(&actual, "testdata/_plugins/bin", args)
 	if err != nil {
 		t.Fatalf(err.Error())
 	}

pkg/plugin/plugin.go

@@ -1,25 +1,28 @@
 package plugin
 
 import (
+	"fmt"
 	"io"
 	"plugin"
 
 	"github.com/spf13/cobra"
 )
 
-func CreateCommandFromPlugin(pluginPath string, out io.Writer, args []string) *cobra.Command {
-	//TODO(howell): Remove these panics
+const badInterfaceFormat = `plugin at %s is missing required function:
+	- NewCommand(func io.writer, []string) *cobra.Command)`
+
+func CreateCommandFromPlugin(pluginPath string, out io.Writer, args []string) (*cobra.Command, error) {
 	plug, err := plugin.Open(pluginPath)
 	if err != nil {
-		panic(err.Error())
+		return nil, fmt.Errorf("plugin at %s could not be opened", pluginPath)
 	}
 	cmdSym, err := plug.Lookup("NewCommand")
 	if err != nil {
-		panic(err.Error())
+		return nil, fmt.Errorf(badInterfaceFormat, pluginPath)
 	}
 	command, ok := cmdSym.(func(io.Writer, []string) *cobra.Command)
 	if !ok {
-		panic("NewCommand does not meet the interface.")
+		return nil, fmt.Errorf(badInterfaceFormat, pluginPath)
 	}
-	return command(out, args)
+	return command(out, args), nil
 }