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/exceptions.h

@@ -21,46 +21,71 @@
 
 #ifndef CAOSDB_EXCEPTIONS_H
 #define CAOSDB_EXCEPTIONS_H
+#include "caosdb/status_code.h"
 #include <stdexcept>
 #include <string>
 
 namespace caosdb::exceptions {
+using caosdb::StatusCode;
 using std::runtime_error;
 
+/**
+ * @brief Generic exception class of the caosdb client library.
+ */
+class Exception : public runtime_error {
+public:
+  explicit Exception(StatusCode code, const std::string &what_arg)
+    : runtime_error(what_arg), code(code) {}
+  [[nodiscard]] inline auto GetCode() const -> StatusCode { return this->code; }
+
+private:
+  StatusCode code;
+};
+
 /**
  * @brief Exception for authentication errors.
  */
-class AuthenticationError : public runtime_error {
+class AuthenticationError : public Exception {
 public:
   explicit AuthenticationError(const std::string &what_arg)
-    : runtime_error(what_arg) {}
+    : Exception(StatusCode::AUTHENTICATION_ERROR, what_arg) {}
 };
 
 /**
  * @brief The connection to the CaosDB server is down.
  */
-class ConnectionError : public runtime_error {
+class ConnectionError : public Exception {
 public:
   explicit ConnectionError(const std::string &what_arg)
-    : runtime_error(what_arg) {}
+    : Exception(StatusCode::CONNECTION_ERROR, what_arg) {}
 };
 
 /**
- * @brief The connection is known to the ConnectionManager under this name.
+ * @brief The transaction terminated unsuccessfully.
  */
-class UnknownConnectionError : public runtime_error {
+class TransactionError : public Exception {
 public:
-  explicit UnknownConnectionError(const std::string &what_arg)
-    : runtime_error(what_arg) {}
+  explicit TransactionError(const std::string &what_arg)
+    : Exception(StatusCode::GENERIC_TRANSACTION_ERROR, what_arg) {}
 };
 
 /**
- * @brief Exception for errors of the ConnectionManager.
+ * @brief Exception for errors of the ConfigurationManager or other components
+ * of the configuration.
  */
-class ConfigurationError : public runtime_error {
+class ConfigurationError : public Exception {
 public:
   explicit ConfigurationError(const std::string &what_arg)
-    : runtime_error(what_arg) {}
+    : Exception(StatusCode::CONFIGURATION_ERROR, what_arg) {}
+};
+
+/**
+ * @brief The connection isn't known to the ConnectionManager under this name.
+ */
+class UnknownConnectionError : public Exception {
+public:
+  explicit UnknownConnectionError(const std::string &what_arg)
+    : Exception(StatusCode::UNKNOWN_CONNECTION_ERROR, what_arg) {}
 };
 
 } // namespace caosdb::exceptions