File Name Not Updated When Rotating Based On Time With Zero Backup

[teklot]

I expect the following code updates the file name when rotating based on the time but it keeps the file name the same as start time.

const auto fileHandler = quill::time_rotating_file_handler(
	logPath, "a",
	quill::FilenameAppend::DateTime,
	"M",
	1U,
	0
);

For example, if the logging starts at 5/4/23 16:25 the I expect the logs rotate every minute as below but that is not the case.

log_2023-05-04_16-25-00.log
log_2023-05-04_16-26-00.log
log_2023-05-04_16-27-00.log
...

Does this make sense?

[odygrd]

When you use quill::FilenameAppend::DateTime it appends the start date and time to the name of the log file. In that case it is using indexes to indicate the rotation otherwise it gets very confusing to read the log file you would had for example :

log_2023-05-04_16-25-00_2023-05-04_16-25-00.log
log_2023-05-04_16-25-00_2023-05-04_16-26-00.log
log_2023-05-04_16-25-00_2023-05-04_16-27-00.log

This example (using master) will achieve what you are looking for

#include "quill/Quill.h"

static char const* base_filename = "logfile.log";

int main()
{
  // Start the backend logging thread
  quill::start();

  // Create a rotating file handler with a max file size per log file and maximum rotation up to 5 times
  std::shared_ptr<quill::Handler> file_handler = quill::time_rotating_file_handler
    (base_filename, "w", quill::FilenameAppend::None, "M", 1, 5);

  // Create a logger using this handler
  quill::Logger* logger_bar = quill::create_logger("rotating", std::move(file_handler));

  for (uint32_t i = 0; i < 15; ++i)
  {
    LOG_INFO(logger_bar, "Hello from {} {}", "rotating logger", i);
    std::this_thread::sleep_for(std::chrono::seconds{61});
  }
}

The most reset logfile has always the name of the base_filename .
When you use backup_count == 0 you will always see logfile.log but it will contain the most reset log
If you change it to backup_count >= 1 then you will see the rotated files

edit : it seems there is a bug at this and I am currently looking

[odygrd]

I have pushed a fix in master for this, it will be in 2.9.1
I tested it with the above example.

Let me know if you still have issues after this fix and thanks for reporting 👍