Initial commit

skills/cli-patterns/templates/context-cli.go

@@ -0,0 +1,152 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/urfave/cli/v2"
+)
+
+// AppContext holds shared state across commands
+type AppContext struct {
+	Config  *Config
+	DB      *sql.DB
+	Verbose bool
+}
+
+// Config represents application configuration
+type Config struct {
+	Host     string
+	Port     int
+	Database string
+}
+
+func main() {
+	app := &cli.App{
+		Name:  "context-demo",
+		Usage: "Demonstration of context and state management",
+		Flags: []cli.Flag{
+			&cli.BoolFlag{
+				Name:    "verbose",
+				Aliases: []string{"v"},
+				Usage:   "Enable verbose output",
+			},
+			&cli.StringFlag{
+				Name:    "config",
+				Aliases: []string{"c"},
+				Usage:   "Path to config file",
+				Value:   "config.yaml",
+			},
+		},
+
+		// Initialize shared context
+		Before: func(c *cli.Context) error {
+			verbose := c.Bool("verbose")
+			configPath := c.String("config")
+
+			if verbose {
+				fmt.Printf("Loading config from: %s\n", configPath)
+			}
+
+			// Create application context
+			appCtx := &AppContext{
+				Config: &Config{
+					Host:     "localhost",
+					Port:     5432,
+					Database: "mydb",
+				},
+				Verbose: verbose,
+			}
+
+			// Simulate database connection
+			// In real app: appCtx.DB, err = sql.Open("postgres", connStr)
+			if verbose {
+				fmt.Println("Connected to database")
+			}
+
+			// Store context in app metadata
+			c.App.Metadata["ctx"] = appCtx
+
+			return nil
+		},
+
+		// Cleanup shared resources
+		After: func(c *cli.Context) error {
+			if ctx, ok := c.App.Metadata["ctx"].(*AppContext); ok {
+				if ctx.DB != nil {
+					// ctx.DB.Close()
+					if ctx.Verbose {
+						fmt.Println("Database connection closed")
+					}
+				}
+			}
+			return nil
+		},
+
+		Commands: []*cli.Command{
+			{
+				Name:  "query",
+				Usage: "Execute a database query",
+				Action: func(c *cli.Context) error {
+					// Retrieve context
+					ctx := c.App.Metadata["ctx"].(*AppContext)
+
+					if ctx.Verbose {
+						fmt.Printf("Connecting to %s:%d/%s\n",
+							ctx.Config.Host,
+							ctx.Config.Port,
+							ctx.Config.Database)
+					}
+
+					fmt.Println("Executing query...")
+					// Use ctx.DB for actual query
+
+					return nil
+				},
+			},
+
+			{
+				Name:  "migrate",
+				Usage: "Run database migrations",
+				Action: func(c *cli.Context) error {
+					// Retrieve context
+					ctx := c.App.Metadata["ctx"].(*AppContext)
+
+					if ctx.Verbose {
+						fmt.Println("Running migrations with context...")
+					}
+
+					fmt.Printf("Migrating database: %s\n", ctx.Config.Database)
+					// Use ctx.DB for migrations
+
+					return nil
+				},
+			},
+
+			{
+				Name:  "status",
+				Usage: "Check database status",
+				Action: func(c *cli.Context) error {
+					// Retrieve context
+					ctx := c.App.Metadata["ctx"].(*AppContext)
+
+					fmt.Printf("Database: %s\n", ctx.Config.Database)
+					fmt.Printf("Host: %s:%d\n", ctx.Config.Host, ctx.Config.Port)
+					fmt.Println("Status: Connected")
+
+					if ctx.Verbose {
+						fmt.Println("Verbose mode: enabled")
+					}
+
+					return nil
+				},
+			},
+		},
+	}
+
+	if err := app.Run(os.Args); err != nil {
+		log.Fatal(err)
+	}
+}