Add implementation of SDL in python

[ric-plt/sdlpy.git] / ricsdl-package / ricsdl / backend / dbbackend_abc.py

diff --git a/ricsdl-package/ricsdl/backend/dbbackend_abc.py b/ricsdl-package/ricsdl/backend/dbbackend_abc.py
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+# Copyright (c) 2019 AT&T Intellectual Property.
+# Copyright (c) 2018-2019 Nokia.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# This source code is part of the near-RT RIC (RAN Intelligent Controller)
+# platform project (RICP).
+#
+
+
+"""The module provides Shared Data Layer (SDL) database backend interface."""
+
+from typing import (Dict, Set, List, Union)
+from abc import ABC, abstractmethod
+
+
+class DbBackendAbc(ABC):
+    """An abstract Shared Data Layer (SDL) class providing database backend interface."""
+
+    @abstractmethod
+    def close(self):
+        """Close database backend connection."""
+        pass
+
+    @abstractmethod
+    def set(self, ns: str, data_map: Dict[str, bytes]) -> None:
+        """Write key value data mapping to database under a namespace."""
+        pass
+
+    @abstractmethod
+    def set_if(self, ns: str, key: str, old_data: bytes, new_data: bytes) -> bool:
+        """"Write key value to database under a namespace if the old value is expected one."""
+        pass
+
+    @abstractmethod
+    def set_if_not_exists(self, ns: str, key: str, data: bytes) -> bool:
+        """"Write key value to database under a namespace if key doesn't exist."""
+        pass
+
+    @abstractmethod
+    def get(self, ns: str, keys: List[str]) -> Dict[str, bytes]:
+        """"Return values of the keys under a namespace."""
+        pass
+
+    @abstractmethod
+    def find_keys(self, ns: str, key_prefix: str) -> List[str]:
+        """"Return all the keys matching search pattern under a namespace in database."""
+        pass
+
+    @abstractmethod
+    def find_and_get(self, ns: str, key_prefix: str, atomic: bool) -> Dict[str, bytes]:
+        """
+        Return all the keys with their values matching search pattern under a namespace in
+        database.
+        """
+        pass
+
+    @abstractmethod
+    def remove(self, ns: str, keys: List[str]) -> None:
+        """Remove keys and their data from database."""
+        pass
+
+    @abstractmethod
+    def remove_if(self, ns: str, key: str, data: bytes) -> bool:
+        """
+           Remove key and its data from database if if the current data value is expected
+           one.
+        """
+        pass
+
+    @abstractmethod
+    def add_member(self, ns: str, group: str, members: Set[bytes]) -> None:
+        """Add new members to a group under a namespace in database."""
+        pass
+
+    @abstractmethod
+    def remove_member(self, ns: str, group: str, members: Set[bytes]) -> None:
+        """Remove members from a group under a namespace in database."""
+        pass
+
+    @abstractmethod
+    def remove_group(self, ns: str, group: str) -> None:
+        """Remove a group under a namespace in database along with it's members."""
+        pass
+
+    @abstractmethod
+    def get_members(self, ns: str, group: str) -> Set[bytes]:
+        """Get all the members of a group under a namespace in database."""
+        pass
+
+    @abstractmethod
+    def is_member(self, ns: str, group: str, member: bytes) -> bool:
+        """Validate if a given member is in the group under a namespace in database."""
+        pass
+
+    @abstractmethod
+    def group_size(self, ns: str, group: str) -> int:
+        """Return the number of members in a group under a namespace in database."""
+        pass
+
+
+class DbBackendLockAbc(ABC):
+    """
+    An abstract Shared Data Layer (SDL) class providing database backend lock interface.
+    Args:
+        ns (str): Namespace under which this lock is targeted.
+        name (str): Lock name, identifies the lock key in a database backend.
+    """
+    def __init__(self, ns: str, name: str) -> None:
+        self._ns = ns
+        self._lock_name = name
+        super().__init__()
+
+    @abstractmethod
+    def acquire(self, retry_interval: Union[int, float] = 0.1,
+                retry_timeout: Union[int, float] = 10) -> bool:
+        """Acquire a database lock."""
+        pass
+
+    @abstractmethod
+    def release(self) -> None:
+        """Release a database lock."""
+        pass
+
+    @abstractmethod
+    def refresh(self) -> None:
+        """Refresh the remaining validity time of the database lock back to a initial value."""
+        pass
+
+    @abstractmethod
+    def get_validity_time(self) -> Union[int, float]:
+        """Return remaining validity time of the lock in seconds."""
+        pass