Better Error Handling and Logging

Summary

Better error handling (less exceptions, more error codes) and logging (for more detailed error handling and configuration issues).

Issue: https://gitlab.indiscale.com/caosdb/customers/lfpb/management/-/issues/390

See also the tests in caosdb-cppinttest!2 (merged)

Focus

• The TransactionStatus class represents the current status of a Transaction instance.
• The TransactionCode is a numeric representation of the status and intended for c-compatible error handling.
• Messages and Message classes handle the errors, warnings and info messages that come from the server.
• Logging: The logging can be configured via a json file. Otherwise the default configuration is in place.
• A lot of code was moved in order to comply with -pedantic flag. Don't waste your time

Test Environment

Unit tests should run as described in README_SETUP

Integration tests should run against a linkahead in the f-grpc branch

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related Issues
• Up-to-date CHANGELOG.md
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there spezifications? Are they satisfied?

For further good practices have a look at our review guidelines.

include/caosdb/transaction_status.h

+/*
+ * This file is a part of the CaosDB Project.
+ *
+ * Copyright (C) 2021 Timm Fitschen <t.fitschen@indiscale.com>
+ * Copyright (C) 2021 IndiScale GmbH <info@indiscale.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef CAOSDB_TRANSACTION_STATUS_H
+#define CAOSDB_TRANSACTION_STATUS_H
+
+/**
+ * TransactionStatus indicates the current status of a transaction and, when it
+ * has already terminated, whether the transaction has been successful or not.
+ *
+ * A status code of 0 denotes a generic success state, positive values indicate
+ * errors, and negative values indicate other states, such as different stages
+ * of a transaction in process.
+ */
+
+#include "caosdb/status_code.h"
+#include "caosdb/exceptions.h"
+#include <memory> // for shared_ptr, unique_ptr
+#include <string> // for string
+
+namespace caosdb::transaction {
+using caosdb::StatusCode;
+using caosdb::exceptions::AuthenticationError;
+using caosdb::exceptions::ConnectionError;
+using caosdb::exceptions::Exception;
+using caosdb::exceptions::TransactionError;
+
+/**
+ * Status of a Request or Transaction.
+ */
+class TransactionStatus {
+public:
+  // REFACTORING NEEDED: When you touch this code again consider writing a
+  // macro, because this is a lot of redundant code here...
+  inline static auto INITIAL() -> const TransactionStatus & {
+    static const TransactionStatus initial(
+      StatusCode::INITIAL, caosdb::get_status_description(StatusCode::INITIAL));
+    return initial;
+  }
+  inline static auto EXECUTING() -> const TransactionStatus & {
+    static const TransactionStatus executing(
+      StatusCode::EXECUTING,
+      caosdb::get_status_description(StatusCode::EXECUTING));
+    return executing;
+  }
+  inline static auto SUCCESS() -> const TransactionStatus & {
+    static const TransactionStatus success(
+      StatusCode::SUCCESS, caosdb::get_status_description(StatusCode::SUCCESS));
+    return success;
+  }
+  inline static auto RPC_ERROR(const std::string &details)
+    -> const TransactionStatus {
+    // We use the GENERIC_RPC_ERROR here because we might want to add further
+    // RPC_ERROR states with different error codes (which stem from GRPC) here
+    // in the future.
+    return TransactionStatus(
+      StatusCode::GENERIC_RPC_ERROR,
+      caosdb::get_status_description(StatusCode::GENERIC_RPC_ERROR) +
+        " Original error: " + details);
+  }
+  inline static auto CONNECTION_ERROR() -> const TransactionStatus & {
+    static const TransactionStatus connection_error(
+      StatusCode::CONNECTION_ERROR,
+      caosdb::get_status_description(StatusCode::CONNECTION_ERROR));
+
+    return connection_error;
+  }
+  inline static auto AUTHENTICATION_ERROR(const std::string &details)
+    -> const TransactionStatus {
+    return TransactionStatus(
+      StatusCode::AUTHENTICATION_ERROR,
+      caosdb::get_status_description(StatusCode::AUTHENTICATION_ERROR) +
+        " Original error: " + details);
+  }
+  inline static auto AUTHENTICATION_ERROR() -> const TransactionStatus & {
+    static const TransactionStatus authentication_error(
+      StatusCode::AUTHENTICATION_ERROR,
+      caosdb::get_status_description(StatusCode::AUTHENTICATION_ERROR));
+
+    return authentication_error;
+  }
+  inline static auto TRANSACTION_ERROR() -> const TransactionStatus & {
+    static const TransactionStatus transaction_error(
+      StatusCode::GENERIC_TRANSACTION_ERROR,
+      caosdb::get_status_description(StatusCode::GENERIC_TRANSACTION_ERROR));
+    return transaction_error;
+  }
+  inline static auto TRANSACTION_ERROR(const std::string &details)
+    -> const TransactionStatus {
+    return TransactionStatus(
+      StatusCode::GENERIC_TRANSACTION_ERROR,
+      caosdb::get_status_description(StatusCode::GENERIC_TRANSACTION_ERROR) +
+        " Original error: " + details);
+  }
+
+  inline auto ThrowExceptionIfError() const -> void {
+    if (!IsError()) {
+      return;
+    }
+    switch (this->code) {
+    case StatusCode::CONNECTION_ERROR:
+      throw ConnectionError(this->description);
+    case StatusCode::AUTHENTICATION_ERROR:
+      throw AuthenticationError(this->description);
+    case StatusCode::GENERIC_TRANSACTION_ERROR:
+      throw TransactionError(this->description);
+    default:
+      throw Exception(StatusCode::GENERIC_ERROR, this->description);
+    }
+  }
+
+  /**
+   * Return true if this TransactionStatus represents a terminated state.
+   */
+  inline auto IsTerminated() const -> bool { return this->code >= 0; };
+
+  /**
+   * Return true if this TransactionStatus represents an erroneous state.
+   */
+  inline auto IsError() const -> bool { return this->code > 0; };
+
+  /**
+   * Return a description of the erroneous state.
+   *
+   * No description yields an empty string.
+   */
+  inline auto GetDescription() const -> const std::string & {
+    return this->description;
+  }
+
+  /**
+   * Return the status code of the state.
+   */
+  inline auto GetCode() const -> StatusCode { return this->code; }
+
+private:
+  /**
+   * The code is an identifier of errors.
+   */
+  StatusCode code;
+
+  /**
+   * Description of the error
+   */
+  std::string description;
+
+  TransactionStatus(StatusCode code, const std::string &description)
+    : code(code), description(description){};
+};
+
+} // namespace caosdb::transaction
+#endif