Initial

backend/internal/rest/seed.go

@@ -0,0 +1,66 @@
+package rest
+
+import (
+	"context"
+	"crypto/rand"
+	"log/slog"
+	"math/big"
+	"strings"
+
+	"goAuth/internal/user"
+)
+
+const (
+	AdminLogin            = "admin"
+	adminPasswordLength   = 16
+	adminPasswordAlphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+)
+
+// seed creates the initial admin user with a random password, but only on the
+// first startup when no users exist yet.
+func seed(ctx context.Context, users *user.Service) error {
+	count, err := users.CountUsers(ctx, true)
+	if err != nil {
+		return err
+	}
+	if count > 0 {
+		return nil
+	}
+
+	password, err := generatePassword(adminPasswordLength)
+	if err != nil {
+		return err
+	}
+
+	admin, err := users.CreateAdmin(ctx, AdminLogin, password)
+	if err != nil {
+		return err
+	}
+
+	slog.Info("seeded admin user",
+		slog.String("op", "rest.seed"),
+		slog.Int64("user_id", admin.Id),
+		slog.String("login", admin.Login),
+		slog.String("password", password),
+	)
+
+	return nil
+}
+
+func generatePassword(length int) (string, error) {
+	alphabetLen := big.NewInt(int64(len(adminPasswordAlphabet)))
+
+	var builder strings.Builder
+	builder.Grow(length)
+
+	for range length {
+		randIndex, err := rand.Int(rand.Reader, alphabetLen)
+		if err != nil {
+			slog.Error("generate admin password", slog.String("op", "rest.generatePassword"), slog.Any("error", err))
+			return "", err
+		}
+		builder.WriteByte(adminPasswordAlphabet[randIndex.Int64()])
+	}
+
+	return builder.String(), nil
+}