--- /dev/null
+#!/usr/bin/env python3
+# Copyright 2022 Canonical Ltd.
+#
+# 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.
+#
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact: legal@canonical.com
+#
+# To get in touch with the maintainers, please contact:
+# osm-charmers@lists.launchpad.net
+#
+# flake8: noqa
+
+import ops
+
+
+class BaseRelationClient(ops.framework.Object):
+ """Requires side of a Kafka Endpoint"""
+
+ def __init__(
+ self, charm: ops.charm.CharmBase, relation_name: str, mandatory_fields: list = []
+ ):
+ super().__init__(charm, relation_name)
+ self.relation_name = relation_name
+ self.mandatory_fields = mandatory_fields
+ self._update_relation()
+
+ def get_data_from_unit(self, key: str):
+ if not self.relation:
+ # This update relation doesn't seem to be needed, but I added it because apparently
+ # the data is empty in the unit tests.
+ # In reality, the constructor is called in every hook.
+ # In the unit tests when doing an update_relation_data, apparently it is not called.
+ self._update_relation()
+ if self.relation:
+ for unit in self.relation.units:
+ data = self.relation.data[unit].get(key)
+ if data:
+ return data
+
+ def get_data_from_app(self, key: str):
+ if not self.relation or self.relation.app not in self.relation.data:
+ # This update relation doesn't seem to be needed, but I added it because apparently
+ # the data is empty in the unit tests.
+ # In reality, the constructor is called in every hook.
+ # In the unit tests when doing an update_relation_data, apparently it is not called.
+ self._update_relation()
+ if self.relation and self.relation.app in self.relation.data:
+ data = self.relation.data[self.relation.app].get(key)
+ if data:
+ return data
+
+ def is_missing_data_in_unit(self):
+ return not all([self.get_data_from_unit(field) for field in self.mandatory_fields])
+
+ def is_missing_data_in_app(self):
+ return not all([self.get_data_from_app(field) for field in self.mandatory_fields])
+
+ def _update_relation(self):
+ self.relation = self.framework.model.get_relation(self.relation_name)
+
+
+class MongoClient(BaseRelationClient):
+ """Requires side of a Mongo Endpoint"""
+
+ mandatory_fields_mapping = {
+ "reactive": ["connection_string"],
+ "ops": ["replica_set_uri", "replica_set_name"],
+ }
+
+ def __init__(self, charm: ops.charm.CharmBase, relation_name: str):
+ super().__init__(charm, relation_name, mandatory_fields=[])
+
+ @property
+ def connection_string(self):
+ if self.is_opts():
+ replica_set_uri = self.get_data_from_unit("replica_set_uri")
+ replica_set_name = self.get_data_from_unit("replica_set_name")
+ return f"{replica_set_uri}?replicaSet={replica_set_name}"
+ else:
+ return self.get_data_from_unit("connection_string")
+
+ def is_opts(self):
+ return not self.is_missing_data_in_unit_ops()
+
+ def is_missing_data_in_unit(self):
+ return self.is_missing_data_in_unit_ops() and self.is_missing_data_in_unit_reactive()
+
+ def is_missing_data_in_unit_ops(self):
+ return not all(
+ [self.get_data_from_unit(field) for field in self.mandatory_fields_mapping["ops"]]
+ )
+
+ def is_missing_data_in_unit_reactive(self):
+ return not all(
+ [self.get_data_from_unit(field) for field in self.mandatory_fields_mapping["reactive"]]
+ )