Add full shop application: Go backend, PostgreSQL, Docker, Caddy and admin panel.

internal/database/db.go

@@ -0,0 +1,51 @@
+package database
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+func Connect(ctx context.Context) (*pgxpool.Pool, error) {
+	dsn := fmt.Sprintf(
+		"postgres://%s:%s@%s:%s/%s?sslmode=disable",
+		getEnv("DB_USER", "shop"),
+		getEnv("DB_PASSWORD", "shop_secret"),
+		getEnv("DB_HOST", "localhost"),
+		getEnv("DB_PORT", "5432"),
+		getEnv("DB_NAME", "shop"),
+	)
+
+	cfg, err := pgxpool.ParseConfig(dsn)
+	if err != nil {
+		return nil, fmt.Errorf("parse config: %w", err)
+	}
+
+	cfg.MaxConns = 10
+	cfg.MinConns = 2
+	cfg.MaxConnLifetime = time.Hour
+
+	pool, err := pgxpool.NewWithConfig(ctx, cfg)
+	if err != nil {
+		return nil, fmt.Errorf("connect: %w", err)
+	}
+
+	for i := 0; i < 30; i++ {
+		if err := pool.Ping(ctx); err == nil {
+			return pool, nil
+		}
+		time.Sleep(time.Second)
+	}
+
+	return nil, fmt.Errorf("database not ready after 30s")
+}
+
+func getEnv(key, fallback string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return fallback
+}