refactor: setup database connection via prerun

cobble.go

@@ -1,37 +1,44 @@
 package main
 
 import (
+	"context"
 	"github.com/spf13/cobra"
 	"log"
 	"os"
 	"strconv"
 )
 
+func SetupDatabaseConnection(cmd *cobra.Command, args []string) {
+	dbPort, _ := strconv.Atoi(os.Getenv("DB_PORT"))
+
+	db := NewDatabase(os.Getenv("DB_HOST"), dbPort)
+	err := db.Connect(os.Getenv("DB_APP_USER"), os.Getenv("DB_APP_PASSWORD"), os.Getenv("DB_NAME"))
+
+	if err != nil {
+		log.Printf("Failed to connect to the database: %s", err)
+		os.Exit(1)
+	}
+
+	cmd.SetContext(context.WithValue(cmd.Context(), "db", db))
+}
+
 var cli = &cobra.Command{
 	Use:   "cobble",
 	Short: "Cobble is a simple SQL migration utility.",
 }
 
 var up = &cobra.Command{
-	Use:   "up",
+	Use:    "up",
-	Short: "Applies migrations",
+	Short:  "Applies migrations",
+	PreRun: SetupDatabaseConnection,
 	Run: func(cmd *cobra.Command, args []string) {
-		dbPort, _ := strconv.Atoi(os.Getenv("DB_PORT"))
+		db := cmd.Context().Value("db").(DB)
-
-		db := NewDatabase(os.Getenv("DB_HOST"), dbPort)
-		err := db.Connect(os.Getenv("DB_APP_USER"), os.Getenv("DB_APP_PASSWORD"), os.Getenv("DB_NAME"))
-
-		if err != nil {
-			log.Printf("Failed to connect to the database: %s", err)
-			os.Exit(1)
-		}
-
 		migrationRoot := args[0]
 		migrationGraph, _ := NewMigrationGraphFromDirectory(migrationRoot)
 		migrationHistory, _ := migrationGraph.GetLinearHistory()
 		for _, migration := range migrationHistory {
 			log.Printf("%s", migration.Name)
-			if err = migration.ApplyMigration(db); err != nil {
+			if err := migration.ApplyMigration(db); err != nil {
 				os.Exit(1)
 			}
 		}