Status of ITK Logger classes?

Niels_Dekker · February 1, 2023, 12:47pm

ITK has this group of Logger and LogOutput classes, originally by Hee-Su Kim, and included with ITK in 2005:

Are they still recommended to be used within a new application? Because they look rather old, and there are more modern third party logging libraries around now.

blowekamp · February 1, 2023, 2:07pm

@Niels_Dekker SimpleITK uses them. They were required to redirect messages from ITK to loggers on different platforms and languages. Here is our example usage:

https://simpleitk.readthedocs.io/en/master/link_Logging_docs.html

And the related C++ classes:

github.com

SimpleITK/SimpleITK/blob/master/Code/Common/include/sitkLogger.h

/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef sitkLogger_h
#define sitkLogger_h

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I see these ITK classes as base classes for derived classes which interact with these third party logging libraries.

Not all messages go through these loggers, especially third party IO libraries.

Niels_Dekker · February 1, 2023, 2:56pm

Thanks @blowekamp So clearly the ITK logger classes are still actively being used

I’m sorry to say I don’t like the output format that much. For example,

logger->Error("Hello ITK Log!\n");

Appears to produce something like:

1675253635.914951324462890625 : (CRITICAL) Hello ITK Log!

This prefix in the output, “time-in-seconds : (CRITICAL)” comes from LoggerBase::BuildFormattedEntry, apparently:

github.com

InsightSoftwareConsortium/ITK/blob/ea231d600298a16396a31742b5f26675e6c6334c/Modules/Core/Common/src/itkLoggerBase.cxx#L71-L95


      
          std::string
          LoggerBase::BuildFormattedEntry(PriorityLevelEnum level, std::string const & content)
          {
            static std::string m_LevelString[] = { "(MUSTFLUSH) ", "(FATAL) ", "(CRITICAL) ", "(WARNING) ",
                                                   "(INFO) ",      "(DEBUG) ", "(NOTSET) " };
            std::ostringstream s;
          
            switch (this->m_TimeStampFormat)
            {
              case TimeStampFormatEnum::REALVALUE:
              {
                s.precision(30);
                s << m_Clock->GetTimeInSeconds();
                break;
              }
              case TimeStampFormatEnum::HUMANREADABLE:
              {
                s << itksys::SystemTools::GetCurrentDateTime(this->m_HumanReadableFormat.c_str());
                break;
              }

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Do you also get the output like that in SimpleITK?

blowekamp · February 1, 2023, 3:25pm

I think a typical usages is some of the itk macros like itkWarningMacro.

I don’t think what SimpleITK using goes through those lines… I recall the extra stuff being added to the message from the macro ( linked above ), that I didn’t think should be in the message.

I think the classes were over engineered (for some old project like IGSTK), and have some dead code and unneeded features.

Niels_Dekker · February 1, 2023, 5:02pm

Thanks @blowekamp but as far as I can see, itkWarningMacro does not use ITK’s Logger classes. (I mean, the classes by Hee-Su Kim). Looking at:

github.com

InsightSoftwareConsortium/ITK/blob/ea231d600298a16396a31742b5f26675e6c6334c/Modules/Core/Common/include/itkMacro.h#L504-L517


      
          /** This macro is used to print warning information (i.e., unusual circumstance
           * but not necessarily fatal.) Example usage looks like:
           * itkWarningMacro(<< "this is warning info" << this->SomeVariable); */
          #define itkWarningMacro(x)                                                   \
            do                                                                         \
            {                                                                          \
              if (itk::Object::GetGlobalWarningDisplay())                              \
              {                                                                        \
                std::ostringstream itkmsg;                                             \
                itkmsg << "WARNING: In " __FILE__ ", line " << __LINE__ << "\n"        \
                       << this->GetNameOfClass() << " (" << this << "): " x << "\n\n"; \
                itk::OutputWindowDisplayWarningText(itkmsg.str().c_str());             \
              }                                                                        \
            } while (0)

Interestingly, ITK’s Logger classes appear to ignore the GlobalWarningDisplay property! They do have their own macro’s, itkLogMacro and itkLogMacroStatic as I see in itkMacro.h.

blowekamp · February 1, 2023, 5:27pm

O, it looks like SimpleITK deals with overriding the OutputWindow class not the Logger class. The two are similar and confusing.