Provide a logging environment

[simatic]

FBAE provides a -v (for "verbose) runtime argument which uses cout to display debugging information. This solution is quite limited as:

• As FBAE is multithreaded, lines get mixed up. In some cases, it is difficult to exploit them.
• It is not possible to decide what is concerned by -v argument (for instance, to decide to diplay only information related to SessionLayer).
• If FBAE is executed on different machines, it is complex to centralize all the traces of an experiment in the same file, for later analysis.

So FBAE must provide a true logging environment like Apache Log4cxx.

[simatic]

Use of Apache Log4cxx must follow the following guidelines:

• Use class structure proposed in Log4cxx quick start so that a file called res/fbae_logger.properties can contain instructions about what to trace during fbae execution.
• Use the following Log4cxx trace levels:
  • FATAL : For Errors causing exit of the program.
  • ERROR : For errors which do not cause exit of the program.
  • WARN : For warnings which are not errors.
  • INFO : For giving information about execution of the program.
  • TRACE and DEBUG should not be used.
• For complex traces, use LOG4CXX_ERROR_FMT() (see its documentation). This has several consequences :
  • *FBAE documentation must be modified to notify Apple Clang computer that, in order to compile fbae, they need to use gcc or pure clang compiler. (this is because apple clang still does not support format C++ 20
  • A source using {fmt} style should #include <format>
  • Thanks to std::format, when we have to display variables of type rank_t or MsgId_t which are actually unint8_t, we do not need anymore to static_cast<unint32_t>(var) as we can specifiy the output format, e.g. LOG4CXX_ERROR_FMT(m_logger, "Error message with unint8_t displayed as int : {:d}", var_of_type_unit8_t);
  • Main CMakeLists.txt must integrate the following lines

    # We want to use Log4cxx format trace capabilities ==> We must set
    # "LOG4CXX_FORMAT_NS" compilation flag to "std" value
    if (MSVC)
    add_compile_options(/DLOG4CXX_FORMAT_NS=std)
    else()
    add_compile_options(-DLOG4CXX_FORMAT_NS=std)
    endif()