Adding support for Non-Genuine mongodb like DocumentDB or CosmosDB #181

toucan_connectors/mongo/mongo_connector.py

@@ -206,6 +206,28 @@ def get_df(self, data_source, permissions=None):
         data_source.query = apply_permissions(data_source.query, permissions)
         return self._retrieve_data(data_source)
 
+    def is_non_genuine(self):
+        # Detect Non-Genuine mongoDB like documentDB or cosmosDB like in mongo compas https://github.com/mongodb-js/data-service/blob/master/lib/instance-detail-helper.js
+        is_genuine = True
+
+        # cosmosDB detection
+        try:
+            build_info = self.client.admin.command("buildinfo")
+            if build_info is None or buildInfo.get('_t') is not None:
+                is_genuine = False
+        except:
+            is_genuine = False
+
+        # documentDB detection
+        try:
+            get_cmd_line_opts = client.admin.command("getCmdLineOpts")
+            if get_cmd_line_opts is None:
+                is_genuine = False
+        except:
+            is_genuine = False
+
+        return not is_genuine
+
     @decorate_func_with_retry
     def get_slice(
         self,
@@ -216,6 +238,16 @@ def get_slice(
     ) -> DataSlice:
         # Create a copy in order to keep the original (deepcopy-like)
         data_source = MongoDataSource.parse_obj(data_source)
+        if self.is_non_genuine() is True:
+            # specific code for Non-Genuine mongoDB who don't have $facet like documentDB or  CosmosDB
+            total_count = MAX_COUNTED_ROWS
+            if offset:
+                data_source.query.append({'$skip': offset})
+            if limit is not None:
+                data_source.query.append({'$limit': limit})
+            df = self.get_df(data_source, permissions)
+            return DataSlice(df, total_count)  
+
         if offset or limit is not None:
             data_source.query = apply_permissions(data_source.query, permissions)
             data_source.query = normalize_query(data_source.query, data_source.parameters)