refactor(storage): refactoring storage (#1459)

Signed-off-by: Laurentiu Niculae <niculae.laurentiu1@gmail.com>

pkg/test/inject/dev.go

@@ -0,0 +1,106 @@
+//go:build dev
+// +build dev
+
+// This file should be linked only in **development** mode.
+
+package inject
+
+import (
+	"net/http"
+	"sync"
+
+	zerr "zotregistry.io/zot/errors"
+	"zotregistry.io/zot/pkg/log"
+)
+
+func Ok(ok bool) bool {
+	if !ok {
+		return ok
+	}
+
+	if injectedFailure() {
+		return false
+	}
+
+	return true
+}
+
+func Error(err error) error {
+	if err != nil {
+		return err
+	}
+
+	if injectedFailure() {
+		return zerr.ErrInjected
+	}
+
+	return nil
+}
+
+// Used to inject error status codes for coverage purposes.
+// -1 will be returned in case of successful failure injection.
+func ErrStatusCode(status int) int {
+	if !injectedFailure() {
+		if status == http.StatusAccepted || status == http.StatusCreated {
+			return status
+		}
+
+		return 0
+	}
+
+	return -1
+}
+
+/**
+ *
+ * Failure injection infrastructure to cover hard-to-reach code paths.
+ *
+ **/
+
+type inject struct {
+	skip int
+}
+
+//nolint:gochecknoglobals // only used by test code
+var injMap sync.Map
+
+func InjectFailure(skip int) bool {
+	gid := log.GoroutineID()
+	if gid < 0 {
+		panic("invalid goroutine id")
+	}
+
+	if _, ok := injMap.Load(gid); ok {
+		panic("prior incomplete fault injection")
+	}
+
+	injst := inject{skip: skip}
+	injMap.Store(gid, injst)
+
+	return true
+}
+
+func injectedFailure() bool {
+	gid := log.GoroutineID()
+
+	val, ok := injMap.Load(gid)
+	if !ok {
+		return false
+	}
+
+	injst, ok := val.(inject)
+	if !ok {
+		panic("invalid type")
+	}
+
+	if injst.skip == 0 {
+		injMap.Delete(gid)
+
+		return true
+	}
+
+	injst.skip--
+	injMap.Store(gid, injst)
+
+	return false
+}