From 109f50bec972dfa5a45919e74a3d599af496865c Mon Sep 17 00:00:00 2001
From: Sangat Das <sangatdas5@gmail.com>
Date: Tue, 12 Jul 2022 01:08:22 -0700
Subject: [PATCH] 1 Test case fails:
 tests/backend/tarantool/test_schema.py::test_drop - AssertionError: assert []
 == ['abci_chains...ta_data', ...]

---
 planetmint/backend/connection.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/planetmint/backend/connection.py b/planetmint/backend/connection.py
index e9da39b..41f91af 100644
--- a/planetmint/backend/connection.py
+++ b/planetmint/backend/connection.py
@@ -20,6 +20,13 @@ BACKENDS = {
 
 logger = logging.getLogger(__name__)
 
+class DBSingleton(type):
+    _instances = {}
+
+    def __call__(cls, *args, **kwargs):
+        if cls not in cls._instances:
+            cls._instances[cls] = super(DBSingleton, cls).__call__(*args, **kwargs)
+        return cls._instances[cls]
 
 def connect(host: str = None, port: int = None, login: str = None, password: str = None, backend: str = None,
                **kwargs):
@@ -81,7 +88,7 @@ def _kwargs_parser(key, kwargs):
         return kwargs[key]
     return None
 
-class Connection:
+class Connection(metaclass=DBSingleton):
     """Connection class interface.
     All backend implementations should provide a connection class that inherits
     from and implements this class.