--- /dev/null
+/*
+ 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.
+*/
+
+/** @file */
+
+#ifndef SHAREDDATALAYER_ERRORQUERIES_HPP_
+#define SHAREDDATALAYER_ERRORQUERIES_HPP_
+
+#include <system_error>
+
+namespace shareddatalayer
+{
+ /** @enum shareddatalayer::Error
+ * @brief Error constants meant for client error handling implementation.
+ *
+ * Certain <code>std::error_code</code>s returned by shareddatalayer can
+ * be compared against these enum values. If returned error can be compared
+ * against these values, it is mentioned in the documentation of the
+ * functionality which returns the <code>std::error_code</code>.
+ *
+ * Descriptions of the <code>shareddatalayer::Error</code> values and
+ * instructions how to handle each value:
+ *
+ * <code>shareddatalayer::Error::SUCCESS</code>:<br>
+ * Request was successfully handled, no error handling needed.
+ *
+ * <code>shareddatalayer::Error::NOT_CONNECTED</code>:<br>
+ * shareddatalayer is not connected to the backend data storage and therefore could not
+ * deliver the request to the backend data storage. Data in the backend data storage
+ * has not been altered.<br>
+ * Client is advised to try the operation again later. If shareddatalayer class,
+ * from which the error originated, contains <code>waitReadyAsync</code> API, client
+ * can use <code>waitReadyAsync</code> API to get a notification once shareddatalayer
+ * is connected to the backend data storage.<br>
+ * Note that if client receives this error for the first SDL API operation which client does,
+ * it is advised to modify client implementation so that client waits for <code>waitReadyAsync</code>
+ * notification before doing any SDL API operations.
+ *
+ * <code>shareddatalayer::Error::OPERATION_INTERRUPTED</code>:<br>
+ * shareddatalayer sent the request to the backend data storage but did not receive a reply from
+ * the backend data storage. In case of a write type request, data in the backend data storage
+ * may or may not have been altered.<br>
+ * Client is advised to try the operation again later. If shareddatalayer class, from which the error originated,
+ * contains waitReadyAsync API, client can use waitReadyAsync API to get a notification once shareddatalayer is
+ * connected to the backend data storage.<br>
+ * When shareddatalayer operations work again, client can choose how to best address the possible loss of consistency.
+ * Client can re-do all the interrupted writes or read the current data in the backend data storage and update it accordingly.
+ *
+ * <code>shareddatalayer::Error::BACKEND_FAILURE</code>:<br>
+ * shareddatalayer delivered the request to the backend data storage but the backend data storage failed to process the request.
+ * In case of a write type request, data in the backend data storage may or may not have been altered.<br>
+ * Client is advised to try the operation again later. Optionally client can also re-create the used shareddatalayer instance.
+ * It is possible that the system does not automatically recover from this type of error situations. Therefore client is advised
+ * to escalate the problem to O&M if operation does not succeed after several retries.<br>
+ * When shareddatalayer operations work again, client can choose how to best address the possible loss of consistency
+ * (see <code>shareddatalayer::Error::OPERATION_INTERRUPTED</code> for possible options).
+ *
+ * <code>shareddatalayer::Error::REJECTED_BY_BACKEND</code>:<br>
+ * shareddatalayer delivered the request to the backend data storage but the backend data storage rejected the request.
+ * In case of a write type request, data in the backend data storage may or may not have been altered.<br>
+ * It is likely that same request will fail repeatedly. It is advised to investigate the exact reason for the failure from the logs.
+ * Reason can be, for example, too many keys in the request or too large data in the request. It is backend specific, what kind of
+ * request is considered invalid. Redis is the most common backend type, maximum supported request parameters with Redis backend
+ * are currently by default following:
+ * maximum amount of keys in request: 524287 keys, maximum key/value size: 512MB.
+ * If the client request is invalid, client implementation needs to be changed. If the reason for invalid request seems to originate
+ * from shareddatalayer, contact shareddatalayer support. <br>
+ * When shareddatalayer operations work again, client can choose how to best address the possible loss of consistency
+ * (see <code>shareddatalayer::Error::OPERATION_INTERRUPTED</code> for possible options).
+ *
+ * <code>shareddatalayer::Error::REJECTED_BY_SDL</code>:<br>
+ * shareddatalayer could not process the request and therefore did not deliver the request to the backend data storage.
+ * Data in the backend data storage has not been altered.<br>
+ * It is likely that same request will fail repeatedly. Reason can be, for example, illegal parameter passed to SDL API function.
+ * It is advised to investigate the exact reason for the failure, for example, by investigating logs and returned <code>std::error_code</code>.
+ * If the client request is invalid, client implementation needs to be changed.<br>
+ */
+ enum class Error
+ {
+ SUCCESS = 0,
+ NOT_CONNECTED,
+ OPERATION_INTERRUPTED,
+ BACKEND_FAILURE,
+ REJECTED_BY_BACKEND,
+ REJECTED_BY_SDL
+ };
+
+ /// @private
+ std::error_condition make_error_condition(shareddatalayer::Error ec);
+}
+
+namespace std
+{
+ /// @private
+ template <>
+ struct is_error_condition_enum<shareddatalayer::Error> : public true_type { };
+}
+
+#endif
Code Review / ric-plt / sdl.git / blobdiff