feat(influx): add completion command for users to generate the comple…

…tions for the influx cli

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### Features
 
+1. [17273](https://github.com/influxdata/influxdb/pull/17273): Add shell completions command for the influx cli
+
 ### Bug Fixes
 
 1. [17240](https://github.com/influxdata/influxdb/pull/17240): NodeJS logo displays properly in Firefox

cmd/influx/completion.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"io"
+
+	"github.com/spf13/cobra"
+)
+
+func completionCmd(rootCmd *cobra.Command) *cobra.Command {
+	writeZSH := func(w io.Writer) error {
+		if err := rootCmd.GenZshCompletion(w); err != nil {
+			return err
+		}
+		_, err := io.WriteString(w, "\ncompdef _influx influx\n")
+		return err
+	}
+
+	return &cobra.Command{
+		Use:       "completion [bash|zsh]",
+		Short:     "Generates completion scripts",
+		Args:      cobra.ExactValidArgs(1),
+		ValidArgs: []string{"bash", "zsh"},
+		Long: `
+	Outputs shell completion for the given shell (bash or zsh)
+
+	OS X:
+		$ source $(brew --prefix)/etc/bash_completion
+		$ influx completion bash > ~/.influx-completion  # for bash users
+		$ influx completion zsh > ~/.influx-completion   # for zsh users
+		$ source ~/.influx-completion
+
+	Ubuntu:
+		$ source /etc/bash-completion
+		$ source <(influx completion bash) # for bash users
+		$ source <(influx completion zsh)  # for zsh users
+
+	Additionally, you may want to output the completion to a file and source in your .bashrc/.zshrc
+`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			switch args[0] {
+			case "bash":
+				return rootCmd.GenBashCompletion(rootCmd.OutOrStdout())
+			case "zsh":
+				return writeZSH(rootCmd.OutOrStdout())
+			}
+			return nil
+		},
+	}
+}

cmd/influx/main.go

@@ -192,6 +192,9 @@ func (b *cmdInfluxBuilder) cmd(childCmdFns ...func(f *globalFlags, opt genericCL
 		c.Flags().BoolP("help", "h", false, fmt.Sprintf("Help for the %s command ", c.Name()))
 	})
 
+	// completion command goes last, after the walk, so that all
+	// commands have every flag listed in the bash|zsh completions.
+	cmd.AddCommand(completionCmd(cmd))
 	return cmd
 }