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