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

@@ -19,24 +19,24 @@
  *
  */
 
+#ifndef CAOSDB_TRANSACTION_H
+#define CAOSDB_TRANSACTION_H
 /**
  * @brief Creation and execution of transactions.
  */
-
-#ifndef CAOSDB_TRANSACTION_H
-#define CAOSDB_TRANSACTION_H
-
 #include <memory>                                // for shared_ptr, unique_ptr
 #include <string>                                // for string
 #include "caosdb/entity.h"                       // for Entity
 #include "caosdb/entity/v1alpha1/main.grpc.pb.h" // for EntityTransactionSe...
 #include "caosdb/entity/v1alpha1/main.pb.h"      // for Entity, RetrieveReq...
+#include "caosdb/transaction_status.h"           // for TransactionStatus
 
 namespace caosdb::transaction {
 using caosdb::entity::Entity;
 using ProtoEntity = caosdb::entity::v1alpha1::Entity;
 using caosdb::entity::v1alpha1::EntityTransactionService;
 using caosdb::entity::v1alpha1::RetrieveRequest;
+using caosdb::transaction::TransactionStatus;
 
 class ResultSet {
 public:
@@ -54,22 +54,50 @@ private:
   std::unique_ptr<Entity> entity;
 };
 
-enum TransactionState { INIT = 10, EXECUTING = 20, SUCCESS = 30, ERROR = 40 };
-
 /**
  * @brief Create a transaction via `CaosDBConnection.createTransaction()`
  */
 class Transaction {
 private:
   std::unique_ptr<ResultSet> result_set;
-  TransactionState state = TransactionState::INIT;
+  TransactionStatus status = TransactionStatus::INITIAL();
   std::shared_ptr<EntityTransactionService::Stub> service_stub;
   RetrieveRequest request; // TODO(tf)
+  std::string error_message;
 
 public:
   Transaction(std::shared_ptr<EntityTransactionService::Stub> service_stub);
   auto RetrieveById(const std::string &id) -> void;
-  auto Execute() -> void;
+
+  /**
+   * Execute this transaction in blocking mode and return the status.
+   */
+  auto Execute() -> TransactionStatus;
+
+  /**
+   * Execute this transaction in non-blocking mode and return immediately.
+   *
+   * A client may request the current status at any time via GetStatus().
+   *
+   * Use WaitForIt() to join the back-ground execution of this transaction.
+   */
+  auto ExecuteAsynchronously() noexcept -> void;
+
+  /**
+   * Join the background execution and return the status when the execution
+   * terminates.
+   *
+   * Use this after ExecuteAsynchronously().
+   */
+  [[nodiscard]] auto WaitForIt() const noexcept -> TransactionStatus;
+
+  /**
+   * Return the current status of the transaction.
+   */
+  [[nodiscard]] inline auto GetStatus() const -> TransactionStatus {
+    return this->status;
+  }
+
   [[nodiscard]] inline auto GetResultSet() const -> const ResultSet & {
     const ResultSet *result_set = this->result_set.get();
     return *result_set;