feat: silence usage information on errors

cli/cmd/root.go

@@ -80,9 +80,28 @@ func GetRootCmd() *cobra.Command {
 	// Cluster administration commands
 	AddAddClusterAdminCmd(rootCmd, opts)
 
+	silenceUsageOnRunErrors(rootCmd)
+
 	return rootCmd
 }
 
+// silenceUsageOnRunErrors prevents Cobra from printing command usage for
+// operational errors returned by RunE. Argument, flag, and required-flag
+// validation happens before RunE, so those errors still include usage.
+func silenceUsageOnRunErrors(command *cobra.Command) {
+	if command.RunE != nil {
+		runE := command.RunE
+		command.RunE = func(cmd *cobra.Command, args []string) error {
+			cmd.Root().SilenceUsage = true
+			return runE(cmd, args)
+		}
+	}
+
+	for _, child := range command.Commands() {
+		silenceUsageOnRunErrors(child)
+	}
+}
+
 // Execute executes the root command. This is called by main.main(). It only needs to happen once to the rootCmd.
 func Execute() {
 	//Disable printing timestamps on log lines

cli/cmd/root_usage_test.go

@@ -0,0 +1,66 @@
+// Copyright (c) Codesphere Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+package cmd
+
+import (
+	"bytes"
+	"errors"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	"github.com/spf13/cobra"
+)
+
+var _ = Describe("command usage on errors", func() {
+	execute := func(root *cobra.Command, args ...string) (string, error) {
+		var output bytes.Buffer
+		root.SetOut(&output)
+		root.SetErr(&output)
+		root.SetArgs(args)
+		err := root.Execute()
+		return output.String(), err
+	}
+
+	newCommandTree := func() (*cobra.Command, *cobra.Command) {
+		root := &cobra.Command{Use: "oms", Args: cobra.NoArgs}
+		child := &cobra.Command{
+			Use:  "install",
+			Args: cobra.NoArgs,
+			RunE: func(*cobra.Command, []string) error {
+				return errors.New("installation failed")
+			},
+		}
+		child.Flags().String("config", "", "installation config")
+		root.AddCommand(child)
+		silenceUsageOnRunErrors(root)
+		return root, child
+	}
+
+	It("does not print usage for an operational RunE error", func() {
+		root, _ := newCommandTree()
+
+		output, err := execute(root, "install")
+
+		Expect(err).To(MatchError("installation failed"))
+		Expect(output).To(ContainSubstring("Error: installation failed"))
+		Expect(output).NotTo(ContainSubstring("Usage:"))
+	})
+
+	DescribeTable("prints usage for invalid command input",
+		func(configure func(*cobra.Command), args []string) {
+			root, child := newCommandTree()
+			configure(child)
+
+			output, err := execute(root, args...)
+
+			Expect(err).To(HaveOccurred())
+			Expect(output).To(ContainSubstring("Usage:"))
+		},
+		Entry("unexpected positional arguments", func(*cobra.Command) {}, []string{"install", "unexpected"}),
+		Entry("unknown flags", func(*cobra.Command) {}, []string{"install", "--unknown"}),
+		Entry("missing required flags", func(command *cobra.Command) {
+			Expect(command.MarkFlagRequired("config")).To(Succeed())
+		}, []string{"install"}),
+	)
+})