feat: status api

internal/repo/fs/fs.go

@@ -161,15 +161,44 @@ func (f *fs) Write(path string, v encoding.BinaryMarshaler) error {
 }
 
 func (f *fs) Read(path string, v encoding.BinaryUnmarshaler) error {
-	if v == nil {
-		return errors.New("can't unmarshal to a nil object")
-	}
-
 	if f.lock == nil {
 		return errors.New("lock must be acquired before read")
 	}
 
-	targetFilePath := filepath.Join(f.root, path)
+	return f.readUnsafe(path, v)
+}
+
+func (f *fs) ReadSafe(path string, v encoding.BinaryUnmarshaler) error {
+	if f.lock != nil {
+		timeout := time.NewTimer(time.Millisecond * 100)
+		checker := time.NewTicker(time.Millisecond)
+	out:
+		for {
+			select {
+			case <-checker.C:
+				if f.lock == nil {
+					checker.Stop()
+					timeout.Stop()
+					break out
+				}
+			case <-timeout.C:
+				checker.Stop()
+				return errors.New("lock acquired, timeout waiting for release")
+			}
+		}
+	}
+
+	return f.readUnsafe(path, v)
+}
+
+// readUnsafe reads the file contents without locking mechanism in mind.
+// Using readUnsafe directly may cause errors if file being written at the moment.
+func (f *fs) readUnsafe(file string, v encoding.BinaryUnmarshaler) error {
+	if v == nil {
+		return errors.New("can't unmarshal to a nil object")
+	}
+
+	targetFilePath := filepath.Join(f.root, file)
 	if targetFilePath == f.lockFilePath() {
 		return errors.New("can't read from the lock file")
 	}