cobra go cli library ignores flags

Question

Here is an snippet from my-tool/cmd/root.go

func Execute() {
    if err := rootCmd.Execute(); err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
}

func init() {
    cobra.OnInitialize(initConfig)

    // Here you will define your flags and configuration settings.
    // Cobra supports persistent flags, which, if defined here,
    // will be global for your application.

    rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.my-tool.yaml)")

    // Cobra also supports local flags, which will only run
    // when this action is called directly.
    rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
}

// initConfig reads in config file and ENV variables if set.
func initConfig() {
    if cfgFile != "" {
        fmt.Println("Config file set")
        // Use config file from the flag.
        viper.SetConfigFile(cfgFile)
    } else {
        fmt.Println("Config file NOT set")
        // Find home directory.
        home, err := homedir.Dir()
        if err != nil {
            fmt.Println(err)
            os.Exit(1)
        }

The code has been generated from the scaffolding process of cobra cli, i.e. via ~/go/cobra/init my-tool --pkg-name github.com/something/my-tool

I am trying to tentatively pass the config flag to check if the program is handling it:

▶ go run main.go  --config "test"

However, though I 'd expect the init() function to make the call to cobra.OnInitialize(initConfig) and parse the flag as indicated by line:

    rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.my-tool.yaml)")

and finally to see one of those two messages in the if statement:

func initConfig() {
    if cfgFile != "" {
        fmt.Println("Config file set")
        // Use config file from the flag.
        viper.SetConfigFile(cfgFile)
    } else {
        fmt.Println("Config file NOT set")
        // Find home directory.
        home, err := homedir.Dir()
        if err != nil {
            fmt.Println(err)
            os.Exit(1)
        }

instead, all I get is the root command's help message; why is that?

edit: from what I see by adding some print statements, the initConfig() is never called (for some reason), i.e. as if cobra.OnInitialize(initConfig) does not do anything.

score 1 · Answer 1 · answered Dec 05 '19 at 15:46

1

You need to Specify your command first

▶ go run main.go "yourcommand" --config "test"

See:

» go run main.go --config "blah"
A longer description that spans multiple lines and likely contains
examples and usage of using your application. For example:
...

» go run main.go preview --config "blah"
Error:  open : no such file or directory
exit status 1

answered Dec 05 '19 at 15:46

Patrick de Kievit

276
3
5

Since I am adding this flag in `root.go`, shouldn't be parsed as a root-level flag (i.e. as I am parsing it?) – pkaramol Dec 05 '19 at 15:53
It gets parsed on root level, but I do think cobra expects a "command" as part of it's syntax. eg. a config file is global for the runtime – Patrick de Kievit Dec 05 '19 at 15:59

cobra go cli library ignores flags

1 Answers1