1 files changed, 31 insertions, 0 deletions
diff --git a/python/mozperftest/mozperftest/metrics/notebook/constant.py b/python/mozperftest/mozperftest/metrics/notebook/constant.py
new file mode 100644
index 0000000000..ca40d289d4
--- /dev/null
+++ b/python/mozperftest/mozperftest/metrics/notebook/constant.py
@@ -0,0 +1,31 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+import os
+import pathlib
+from types import MappingProxyType
+
+from .transformer import get_transformers
+
+
+class Constant(object):
+    """A singleton class to store all constants."""
+
+    __instance = None
+
+    def __new__(cls, *args, **kw):
+        if cls.__instance is None:
+            cls.__instance = object.__new__(cls, *args, **kw)
+        return cls.__instance
+
+    def __init__(self):
+        self.__here = pathlib.Path(os.path.dirname(os.path.abspath(__file__)))
+        self.__predefined_transformers = get_transformers(self.__here / "transforms")
+
+    @property
+    def predefined_transformers(self):
+        return MappingProxyType(self.__predefined_transformers).copy()
+
+    @property
+    def here(self):
+        return self.__here