Add support for bash/zsh completion

cmd/fluxctl/completion_cmd.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/spf13/cobra"
+)
+
+var (
+	completionShells = map[string]func(out io.Writer, cmd *cobra.Command) error{
+		"bash": runCompletionBash,
+		"zsh":  runCompletionZsh,
+	}
+)
+
+func newCompletionCommand() *cobra.Command {
+	shells := []string{}
+	for s := range completionShells {
+		shells = append(shells, s)
+	}
+
+	return &cobra.Command{
+		Use:                   "completion SHELL",
+		DisableFlagsInUseLine: true,
+		Short:                 "Output shell completion code for the specified shell (bash or zsh)",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(args) == 0 {
+				return newUsageError("please specify a shell")
+			}
+
+			if len(args) > 1 {
+				return newUsageError(fmt.Sprintf("please specify one of the following shells: %s", strings.Join(shells, " ")))
+			}
+
+			run, found := completionShells[args[0]]
+			if !found {
+				return newUsageError(fmt.Sprintf("unsupported shell type %q.", args[0]))
+			}
+
+			return run(cmd.OutOrStdout(), cmd.Parent())
+		},
+		ValidArgs: shells,
+	}
+}
+
+func runCompletionBash(out io.Writer, fluxctl *cobra.Command) error {
+	return fluxctl.GenBashCompletion(out)
+}
+
+func runCompletionZsh(out io.Writer, fluxctl *cobra.Command) error {
+	return fluxctl.GenZshCompletion(out)
+}

cmd/fluxctl/completion_cmd_test.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestCompletionCommand_InputFailure(t *testing.T) {
+	for k, v := range [][]string{
+		{},
+		{"foo"},
+		{"bash", "zsh"},
+	} {
+		t.Run(fmt.Sprintf("%d", k), func(t *testing.T) {
+			cmd := newCompletionCommand()
+			cmd.SetArgs(v)
+			if err := cmd.Execute(); err == nil {
+				t.Fatalf("Expecting error: command is expecting either bash or zsh")
+			}
+		})
+	}
+}
+
+func TestCompletionCommand_Success(t *testing.T) {
+	for k, v := range [][]string{
+		{"bash"},
+		{"zsh"},
+	} {
+		t.Run(fmt.Sprintf("%d", k), func(t *testing.T) {
+			parentCmd := newRoot().Command()
+			cmd := newCompletionCommand()
+			parentCmd.AddCommand(cmd)
+			cmd.SetArgs(v)
+			if err := cmd.Execute(); err != nil {
+				t.Fatalf("Expecting nil, got error (%s)", err.Error())
+			}
+		})
+	}
+}

cmd/fluxctl/root_cmd.go

@@ -97,6 +97,7 @@ func (opts *rootOpts) Command() *cobra.Command {
 		newIdentity(opts).Command(),
 		newSync(opts).Command(),
 		newInstall().Command(),
+		newCompletionCommand(),
 	)
 
 	return cmd
@@ -105,7 +106,7 @@ func (opts *rootOpts) Command() *cobra.Command {
 func (opts *rootOpts) PersistentPreRunE(cmd *cobra.Command, _ []string) error {
 	// skip port forward for certain commands
 	switch cmd.Use {
-	case "version":
+	case "version", "completion SHELL":
 		fallthrough
 	case "install":
 		return nil