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.h

@@ -54,7 +54,7 @@ private:
   std::unique_ptr<Entity> entity;
 };
 
-enum TransactionState { INIT = 10, EXECUTING = 20, SUCCESS = 30, ERROR = 40 };
+enum TransactionState { TS_INIT = 10, TS_EXECUTING = 20, TS_SUCCESS = 30, TS_ERROR = 40 };
 
 /**
  * @brief Create a transaction via `CaosDBConnection.createTransaction()`
@@ -62,7 +62,7 @@ enum TransactionState { INIT = 10, EXECUTING = 20, SUCCESS = 30, ERROR = 40 };
 class Transaction {
 private:
   std::unique_ptr<ResultSet> result_set;
-  TransactionState state = TransactionState::INIT;
+  TransactionState state = TransactionState::TS_INIT;
   std::shared_ptr<EntityTransactionService::Stub> service_stub;
   RetrieveRequest request; // TODO(tf)