use default value for required arg if not provided

[pkbhowmick]

what

why

references

• DEV-2327

[osterman]

@pkbhowmick this PR is now in conflict

[osterman]

Please add something to this page: https://atmos.tools/core-concepts/custom-commands/

[osterman]

@coderabbitai can you suggest the changes to documentation related to this PR

[coderabbitai]

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@osterman, here's a suggestion for updating the documentation related to this PR:

Add a section to the Custom Commands documentation explaining that atmos now uses the default value for a required argument if it's not provided. This enhances flexibility when invoking custom commands.

For example, you could add:

### Default Values for Required Arguments

Atmos allows you to define default values for required arguments in your custom commands. If a required argument is not provided when the command is invoked, atmos will use the specified default value.

**Example:**

Given a custom command configuration:

```yaml
commands:
  deploy-stack:
    description: "Deploy a stack."
    arguments:
      - name: "environment"
        description: "The environment to deploy."
        required: true
        default: "dev"

You can now run:

atmos deploy-stack

Atmos will use "dev" as the default value for the environment argument.

This update will inform users about the new behavior introduced in this PR.

[pkbhowmick]

Hi @osterman
In my findings, I have found cobra cli only support for default value of flags only, we can't pass default value of args.

I believe there is order related issue too for commands who have multiple arguments. Please correct me in case I miss something.

[osterman]

I think you're right that it doesn't support it natively, but I think they address the use-case in their docs.

https://github.com/spf13/cobra/blob/main/site/content/user_guide.md#positional-and-custom-arguments

The gist of it is I think you need to check args directly, and use the defaults manually.

Example of the logic:

var exampleCmd = &cobra.Command{
    Use:   "example [arg1] [arg2]",
    Short: "An example command",
    Args:  cobra.MaximumNArgs(2),
    Run: func(cmd *cobra.Command, args []string) {
        arg1 := "default1"
        arg2 := "default2"

        if len(args) > 0 {
            arg1 = args[0]
        }
        if len(args) > 1 {
            arg2 = args[1]
        }

        fmt.Printf("Arg1: %s, Arg2: %s\n", arg1, arg2)
    },
}