golang-spf13-cobra

Build a Go CLI command tree in cobra by defining root and subcommands with the RunE hook for predictable error propagation and exit behavior. This lifecycle hook ensures predictable exit behavior across many commands instead of manual error handling.

Validate command arguments in cobra using built-in and custom Args validators like MatchAll to fail fast with standard error messaging. This replaces manual len(args) checks by enforcing constraints directly in the command tree definition.

Add shell completion to a Go CLI by implementing ValidArgsFunction for positional arguments and RegisterFlagCompletionFunc for flags. These cobra features enable dynamic shell completions that feel native to the terminal environment.

Test cobra command output safely by using cmd.OutOrStdout() and cmd.ErrOrStderr() to capture output, and instantiating a fresh command tree per test. This isolation ensures consistent testable output handling across many commands.

Generate documentation from a cobra command tree in man, markdown, and YAML formats. The command tree structure directly supports cobra-based docs generation, producing consistent help and usage behavior for your Go CLI.

Persistent flags propagate down to subcommands while local flags apply only to the specific command in a cobra CLI. You can enforce constraints like required, mutually exclusive, or required-together flags across the command tree.