Golang Cli

package main

import (
	"fmt"

	"github.com/spf13/cobra"
)

// Cobra provides built-in validators for positional arguments.
// See the table in SKILL.md for all available validators.
var deployCmd = &cobra.Command{
	Use:   "deploy [environment]",
	Short: "Deploy to an environment",
	Args:  cobra.ExactArgs(1),
	RunE: func(cmd *cobra.Command, args []string) error {
		env := args[0]
		_ = env
		// deploy...
		return nil
	},
}

// Custom validation example:
var deployWithValidationCmd = &cobra.Command{
	Use:   "deploy [environment]",
	Short: "Deploy to an environment",
	Args: func(cmd *cobra.Command, args []string) error {
		if len(args) != 1 {
			return fmt.Errorf("expected exactly 1 argument, got %d", len(args))
		}
		valid := map[string]bool{"dev": true, "staging": true, "prod": true}
		if !valid[args[0]] {
			return fmt.Errorf("invalid environment %q, must be one of: dev, staging, prod", args[0])
		}
		return nil
	},
	RunE: func(cmd *cobra.Command, args []string) error {
		// deploy...
		return nil
	},
}


package main

import (
	"bytes"
	"testing"

	"github.com/spf13/cobra"
)

// Test commands by executing them programmatically and capturing output.
// Use cmd.OutOrStdout() and cmd.ErrOrStderr() in commands (instead of
// os.Stdout / os.Stderr) so output can be captured in tests.

func executeCommand(root *cobra.Command, args ...string) (string, error) {
	buf := new(bytes.Buffer)
	root.SetOut(buf)
	root.SetErr(buf)
	root.SetArgs(args)
	err := root.Execute()
	return buf.String(), err
}

func TestServeCommand(t *testing.T) {
	tests := []struct {
		name    string
		args    []string
		want    string
		wantErr bool
	}{
		{
			name: "default port",
			args: []string{"serve"},
			want: "listening on :8080\n",
		},
		{
			name: "custom port",
			args: []string{"serve", "--port", "9090"},
			want: "listening on :9090\n",
		},
		{
			name:    "missing required flag",
			args:    []string{"serve", "--host", ""},
			wantErr: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, err := executeCommand(rootCmd, tt.args...)
			if (err != nil) != tt.wantErr {
				t.Errorf("error = %v, wantErr %v", err, tt.wantErr)
			}
			if !tt.wantErr && got != tt.want {
				t.Errorf("output = %q, want %q", got, tt.want)
			}
		})
	}
}


package main

import (
	"os"

	"github.com/spf13/cobra"
)

// === Shell Completion Command ===
// Cobra generates completions for bash, zsh, fish, and PowerShell automatically.

func init() {
	rootCmd.AddCommand(&cobra.Command{
		Use:       "completion [bash|zsh|fish|powershell]",
		Short:     "Generate shell completion script",
		Args:      cobra.ExactValidArgs(1),
		ValidArgs: []string{"bash", "zsh", "fish", "powershell"},
		RunE: func(cmd *cobra.Command, args []string) error {
			switch args[0] {
			case "bash":
				return rootCmd.GenBashCompletionV2(os.Stdout, true)
			case "zsh":
				return rootCmd.GenZshCompletion(os.Stdout)
			case "fish":
				return rootCmd.GenFishCompletion(os.Stdout, true)
			case "powershell":
				return rootCmd.GenPowerShellCompletionWithDesc(os.Stdout)
			}
			return nil
		},
	})
}

// === Custom Completions ===
// Add custom completions for flags and arguments.

func customCompletionExamples() {
	deployCmd.RegisterFlagCompletionFunc("env", func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
		return []string{
			"dev\tDevelopment environment",
			"staging\tStaging environment",
			"prod\tProduction environment",
		}, cobra.ShellCompDirectiveNoFileComp
	})

	// Dynamic argument completion
	deployCmd.ValidArgsFunction = func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
		if len(args) != 0 {
			return nil, cobra.ShellCompDirectiveNoFileComp
		}
		return getAvailableServices(), cobra.ShellCompDirectiveNoFileComp
	}
}

func getAvailableServices() []string {
	// fetch available services dynamically
	return nil
}


package main

import (
	"fmt"
	"log/slog"
	"os"
	"strings"