Initial commit

skills/cli-patterns/examples/db-cli/README.md

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+# Database CLI Tool Example
+
+Complete database management CLI demonstrating:
+- Command categories (Schema, Data, Admin)
+- Before hook for connection validation
+- After hook for cleanup
+- Required and optional flags
+- Environment variable fallbacks
+
+## Usage
+
+```bash
+# Set connection string
+export DATABASE_URL="postgres://user:pass@localhost/mydb"
+
+# Run migrations
+dbctl migrate
+dbctl migrate --direction down --steps 2
+
+# Rollback
+dbctl rollback
+
+# Seed database
+dbctl seed --file seeds/test-data.sql
+
+# Backup and restore
+dbctl backup --output backups/db-$(date +%Y%m%d).sql
+dbctl restore --input backups/db-20240101.sql
+
+# Admin tasks
+dbctl status
+dbctl vacuum
+
+# Verbose output
+dbctl -v migrate
+```
+
+## Features Demonstrated
+
+1. **Command Categories**: Schema, Data, Admin
+2. **Global Flags**: --connection, --verbose
+3. **Before Hook**: Validates connection before any command
+4. **After Hook**: Closes connections after command completes
+5. **Required Flags**: backup/restore require file paths
+6. **Environment Variables**: DATABASE_URL fallback
+7. **Flag Aliases**: -v for --verbose, -d for --direction

skills/cli-patterns/examples/db-cli/main.go

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+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/urfave/cli/v2"
+)
+
+func main() {
+	app := &cli.App{
+		Name:  "dbctl",
+		Usage: "Database management CLI tool",
+		Flags: []cli.Flag{
+			&cli.StringFlag{
+				Name:     "connection",
+				Aliases:  []string{"conn"},
+				Usage:    "Database connection string",
+				EnvVars:  []string{"DATABASE_URL"},
+				Required: true,
+			},
+			&cli.BoolFlag{
+				Name:    "verbose",
+				Aliases: []string{"v"},
+				Usage:   "Enable verbose output",
+			},
+		},
+
+		Before: func(c *cli.Context) error {
+			conn := c.String("connection")
+			verbose := c.Bool("verbose")
+
+			if verbose {
+				fmt.Println("🔗 Validating database connection...")
+			}
+
+			// Validate connection string
+			if conn == "" {
+				return fmt.Errorf("database connection string required")
+			}
+
+			if verbose {
+				fmt.Println("✅ Connection string validated")
+			}
+
+			return nil
+		},
+
+		After: func(c *cli.Context) error {
+			if c.Bool("verbose") {
+				fmt.Println("🔚 Closing database connections...")
+			}
+			return nil
+		},
+
+		Commands: []*cli.Command{
+			// Schema category
+			{
+				Name:     "migrate",
+				Category: "Schema",
+				Usage:    "Run database migrations",
+				Flags: []cli.Flag{
+					&cli.StringFlag{
+						Name:    "direction",
+						Aliases: []string{"d"},
+						Usage:   "Migration direction (up/down)",
+						Value:   "up",
+					},
+					&cli.IntFlag{
+						Name:  "steps",
+						Usage: "Number of steps to migrate",
+						Value: 0,
+					},
+				},
+				Action: func(c *cli.Context) error {
+					direction := c.String("direction")
+					steps := c.Int("steps")
+
+					fmt.Printf("Running migrations %s", direction)
+					if steps > 0 {
+						fmt.Printf(" (%d steps)", steps)
+					}
+					fmt.Println()
+
+					return nil
+				},
+			},
+			{
+				Name:     "rollback",
+				Category: "Schema",
+				Usage:    "Rollback last migration",
+				Action: func(c *cli.Context) error {
+					fmt.Println("Rolling back last migration...")
+					return nil
+				},
+			},
+
+			// Data category
+			{
+				Name:     "seed",
+				Category: "Data",
+				Usage:    "Seed database with test data",
+				Flags: []cli.Flag{
+					&cli.StringFlag{
+						Name:    "file",
+						Aliases: []string{"f"},
+						Usage:   "Seed file path",
+						Value:   "seeds/default.sql",
+					},
+				},
+				Action: func(c *cli.Context) error {
+					file := c.String("file")
+					fmt.Printf("Seeding database from: %s\n", file)
+					return nil
+				},
+			},
+			{
+				Name:     "backup",
+				Category: "Data",
+				Usage:    "Backup database",
+				Flags: []cli.Flag{
+					&cli.StringFlag{
+						Name:     "output",
+						Aliases:  []string{"o"},
+						Usage:    "Backup output path",
+						Required: true,
+					},
+				},
+				Action: func(c *cli.Context) error {
+					output := c.String("output")
+					fmt.Printf("Backing up database to: %s\n", output)
+					return nil
+				},
+			},
+			{
+				Name:     "restore",
+				Category: "Data",
+				Usage:    "Restore database from backup",
+				Flags: []cli.Flag{
+					&cli.StringFlag{
+						Name:     "input",
+						Aliases:  []string{"i"},
+						Usage:    "Backup file path",
+						Required: true,
+					},
+				},
+				Action: func(c *cli.Context) error {
+					input := c.String("input")
+					fmt.Printf("Restoring database from: %s\n", input)
+					return nil
+				},
+			},
+
+			// Admin category
+			{
+				Name:     "status",
+				Category: "Admin",
+				Usage:    "Check database status",
+				Action: func(c *cli.Context) error {
+					fmt.Println("Database Status:")
+					fmt.Println("  Connection: Active")
+					fmt.Println("  Tables: 15")
+					fmt.Println("  Size: 245 MB")
+					return nil
+				},
+			},
+			{
+				Name:     "vacuum",
+				Category: "Admin",
+				Usage:    "Optimize database",
+				Action: func(c *cli.Context) error {
+					fmt.Println("Optimizing database...")
+					return nil
+				},
+			},
+		},
+	}
+
+	if err := app.Run(os.Args); err != nil {
+		log.Fatal(err)
+	}
+}