feat: complete OCI registry implementation with docker push/pull support

A lightweight OCI (Open Container Initiative) registry implementation written in Go.

internal/module/registry/catalog.go

@@ -0,0 +1,66 @@
+package registry
+
+import (
+	"strconv"
+	"strings"
+
+	"gitea.loveuer.com/loveuer/cluster/internal/model"
+	"gitea.loveuer.com/loveuer/cluster/pkg/resp"
+	"gitea.loveuer.com/loveuer/cluster/pkg/store"
+	"github.com/gofiber/fiber/v3"
+	"gorm.io/gorm"
+)
+
+// HandleCatalog ????????
+// GET /v2/_catalog?n={limit}&last={last}
+func HandleCatalog(c fiber.Ctx, db *gorm.DB, store store.Store) error {
+	path := c.Path()
+
+	// ????: /v2/_catalog
+	parts := strings.Split(strings.TrimPrefix(path, "/v2/"), "/")
+	if len(parts) < 1 || parts[0] != "_catalog" {
+		return resp.R404(c, "INVALID_PATH", nil, "invalid path")
+	}
+
+	// ??????
+	nStr := c.Query("n", "100")
+	n, err := strconv.Atoi(nStr)
+	if err != nil || n <= 0 {
+		n = 100
+	}
+	last := c.Query("last")
+
+	// ????
+	var repos []model.Repository
+	query := db.Order("name ASC").Limit(n + 1)
+
+	if last != "" {
+		query = query.Where("name > ?", last)
+	}
+
+	if err := query.Find(&repos).Error; err != nil {
+		return resp.R500(c, "", nil, err)
+	}
+
+	// ????
+	repoNames := make([]string, 0, len(repos))
+	hasMore := false
+	for i, repo := range repos {
+		if i >= n {
+			hasMore = true
+			break
+		}
+		repoNames = append(repoNames, repo.Name)
+	}
+
+	response := map[string]interface{}{
+		"repositories": repoNames,
+	}
+
+	// ??????????????
+	if hasMore && len(repoNames) > 0 {
+		response["last"] = repoNames[len(repoNames)-1]
+	}
+
+	return resp.R200(c, response)
+}