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/configuration.h

@@ -21,17 +21,20 @@
 
 #ifndef CAOSDB_CONFIGURATION_H
 #define CAOSDB_CONFIGURATION_H
-#include <memory>                          // for unique_ptr
-#include <string>                          // for string
 #include "boost/filesystem/operations.hpp" // for exists
 #include "boost/filesystem/path.hpp"       // for path
 #include "boost/json/object.hpp"           // for object
 #include "boost/json/value.hpp"            // for value
-#include "boost/json/value_ref.hpp"        // for array, object
+#include "boost/json/value_ref.hpp"        // IWYU pragma: keep
 #include "caosdb/authentication.h"         // for Authenticator, PlainPassw...
-#include "caosdb/connection.h" // for ConnectionConfiguration, Certifi...
-#include "caosdb/exceptions.h" // for ConfigurationError
-#include "caosdb/utility.h"    // for load_json_file
+#include "caosdb/certificate_provider.h"   // for CertificateProvider, path
+#include "caosdb/exceptions.h"             // for ConfigurationError
+#include "caosdb/logging.h"
+#include "caosdb/utility.h"              // for load_json_file
+#include "grpcpp/security/credentials.h" // for ChannelCredentials
+#include <iosfwd>                        // for ostream
+#include <memory>                        // for unique_ptr, shared_ptr
+#include <string>                        // for string
 
 namespace caosdb::configuration {
 using boost::filesystem::exists;
@@ -41,14 +44,89 @@ using boost::json::object;
 using boost::json::value;
 using caosdb::authentication::Authenticator;
 using caosdb::authentication::PlainPasswordAuthenticator;
-using caosdb::connection::CertificateProvider;
-using caosdb::connection::ConnectionConfiguration;
-using caosdb::connection::ConnectionManager;
-using caosdb::connection::InsecureConnectionConfiguration;
-using caosdb::connection::PemFileCertificateProvider;
-using caosdb::connection::TlsConnectionConfiguration;
 using caosdb::exceptions::ConfigurationError;
 using caosdb::utility::load_json_file;
+using grpc::ChannelCredentials;
+
+const std::string logger_name = "caosdb::configuration";
+
+/**
+ * @brief Configuration of the CaosDB connection.
+ */
+class ConnectionConfiguration {
+private:
+  std::string host;
+  int port;
+
+public:
+  ConnectionConfiguration(const std::string &host, int port);
+  virtual ~ConnectionConfiguration() = default;
+  friend auto operator<<(std::ostream &out,
+                         const ConnectionConfiguration &configuration)
+    -> std::ostream &;
+
+  [[nodiscard]] auto virtual ToString() const -> std::string = 0;
+  [[nodiscard]] auto GetHost() const -> std::string;
+  [[nodiscard]] auto GetPort() const -> int;
+  [[nodiscard]] auto virtual GetChannelCredentials() const
+    -> std::shared_ptr<ChannelCredentials> = 0;
+};
+
+class InsecureConnectionConfiguration : public ConnectionConfiguration {
+private:
+  std::shared_ptr<ChannelCredentials> credentials;
+
+public:
+  InsecureConnectionConfiguration(const std::string &host, int port);
+  [[nodiscard]] auto GetChannelCredentials() const
+    -> std::shared_ptr<ChannelCredentials> override;
+  [[nodiscard]] auto ToString() const -> std::string override;
+};
+
+class TlsConnectionConfiguration : public ConnectionConfiguration {
+private:
+  std::shared_ptr<ChannelCredentials> credentials;
+  std::string certificate_provider;
+
+public:
+  TlsConnectionConfiguration(const std::string &host, int port);
+  TlsConnectionConfiguration(const std::string &host, int port,
+                             const Authenticator &authenticator);
+  TlsConnectionConfiguration(const std::string &host, int port,
+                             const CertificateProvider &certificate_provider);
+  TlsConnectionConfiguration(const std::string &host, int port,
+                             const CertificateProvider &certificate_provider,
+                             const Authenticator &authenticator);
+  [[nodiscard]] auto GetChannelCredentials() const
+    -> std::shared_ptr<ChannelCredentials> override;
+  [[nodiscard]] auto ToString() const -> std::string override;
+};
+
+/**
+ * Helper class (no state, just member functions) which should only be used by
+ * the ConfigurationManager to initialize the logging framework from the stored
+ * configuration.
+ */
+class LoggingConfigurationHelper {
+public:
+  friend class ConfigurationManager;
+
+private:
+  auto CreateConsoleSinkConfiguration(const object &from,
+                                      const std::string &name, int level) const
+    -> std::shared_ptr<caosdb::logging::SinkConfiguration>;
+  auto CreateSyslogSinkConfiguration(const object &from,
+                                     const std::string &name, int level) const
+    -> std::shared_ptr<caosdb::logging::SinkConfiguration>;
+  auto CreateFileSinkConfiguration(const object &from, const std::string &name,
+                                   int level) const
+    -> std::shared_ptr<caosdb::logging::SinkConfiguration>;
+  auto CreateSinkConfiguration(const object &from, const std::string &name,
+                               int default_level) const
+    -> std::shared_ptr<caosdb::logging::SinkConfiguration>;
+  auto CreateLoggingConfiguration(const object &from) const
+    -> caosdb::logging::LoggingConfiguration;
+};
 
 /**
  * Helper class (no state, just member functions) which should only be used by
@@ -63,7 +141,7 @@ private:
   /**
    * @param from - a single connection configuration.
    */
-  inline auto CreateCertificateProvider(const object &from) const
+  auto CreateCertificateProvider(const object &from) const
     -> std::unique_ptr<CertificateProvider>;
 
   /**
@@ -110,12 +188,12 @@ public:
   /**
    * See mReset.
    */
-  inline static auto Reset() -> void { GetInstance().mReset(); }
+  inline static auto Reset() noexcept -> int { return GetInstance().mReset(); }
 
   /**
    * See mClear.
    */
-  inline static auto Clear() -> void { GetInstance().mClear(); }
+  inline static auto Clear() noexcept -> int { return GetInstance().mClear(); }
 
   /**
    * See mLoadSingleJSONConfiguration.
@@ -155,6 +233,8 @@ public:
 private:
   value json_configuration;
   ConnectionConfigurationHelper connection_configuration_helper;
+  LoggingConfigurationHelper logging_configuration_helper;
+
   inline ConfigurationManager() { InitializeDefaults(); };
 
   /**
@@ -164,7 +244,7 @@ private:
    * first existing file from the LIBCAOSDB_CONFIGURATION_FILES_PRECEDENCE list
    * of file locations.
    */
-  auto InitializeDefaults() -> void;
+  auto InitializeDefaults() -> int;
 
   /**
    * Return a json object representing the current configuration.
@@ -188,7 +268,7 @@ private:
    * The current configuration is deleted and a new configuration is being
    * loaded via InitializeDefaults.
    */
-  auto mReset() -> void;
+  auto mReset() noexcept -> int;
 
   /**
    * Clear this ConfigurationManager.
@@ -198,7 +278,7 @@ private:
    * In contrast to mReset, this method only deletes the current configuration
    * but does not load a new one via InitializeDefaults.
    */
-  auto mClear() -> void;
+  auto mClear() noexcept -> int;
 
   /**
    * Load a configuration from a json file.