Developing CLI Apps

CLI Application Development

Standards for building CLI applications in Go. Currently uses Cobra for command structure and Huh for interactive UI.

Interactive UI patterns: See Interactive UI Reference

Command Organization

• One file per command in cmd/, file name matches command name (camelCase)
• All commands registered in their own init() function via rootCmd.AddCommand()
• See cmd/root.go for the root command structure and initialization chain
• See any existing command file (e.g., cmd/version.go) for a minimal example

Adding a New Command

1. Create a new file in cmd/ (camelCase name matching the command)
2. Define a cobra.Command variable with Use and Short fields
3. In init(): register with rootCmd.AddCommand(), define flags, bind to Viper
4. Suppress the init lint: //nolint:gochecknoinits // Cobra requires an init function to set up the command structure.

Flag Conventions

• Use StringVar/BoolVar/CountVarP (pointer-binding) for all flags
• Bind every flag to Viper: viper.BindPFlag("name", cmd.Flags().Lookup("name"))
• Use kebab-case for flag names: --git-clone-protocol, not --gitCloneProtocol
• Provide meaningful defaults and descriptions

Initialization Chain

Global dependencies are initialized via cobra.OnInitialize() in root.go. Each initializer sets a package-level global. Order matters — later initializers may depend on earlier ones. Read root.go for the current chain.

Error Handling in Commands

• Use Run (not RunE) — errors are handled inline with logger.Error() + os.Exit(1)
• Use logger.Success() for positive completion messages
• Keep Run functions thin — delegate to business logic in lib/

Signal Handling and Cleanup

• Signal handlers are registered in setupCleanup() in root.go
• PersistentPostRun on root command handles successful completion cleanup
• Separate cleanupAndExit() function for error/signal paths
• Always clean up resources (loggers, temp files) on all exit paths

Non-Interactive Mode

The --non-interactive flag:

• Disables all interactive prompts (Huh forms)
• Disables progress indicators
• Uses automatic defaults or explicit flag values instead
• Enables CI/CD and scripted usage

Output Modes

See GetDisplayMode() in root.go for the resolution logic.

Key Rules

• Commands should not import each other; share state via package-level variables in cmd/
• Use fmt.Fprint(os.Stderr, ...) for error output, logger for structured messages
• Always respect --non-interactive in any new interactive functionality