close and re-create/-open log file(s) on SIGNAL

[sock3t]

Challenge:
To maintain log file disk usage you have to accomplish 2 main points:

• rotate and compress the log files regularly
• get rid of old logs after a certain expiration time

Proposed solution:
A solution to this is possible today already via logrotate:
https://www.traccar.org/forums/topic/log-file-size/#post-72460

Also considered but much more effort:
#3994
^^ this might be another option but would required integration with a variety of syslogging products. It has to be considered that Traccar is used on other platforms apart from Linux+rsyslog.

Why logrotate?
Logrotate or other similar log rotation mechanisms don't require complex integration and code change but mostly work out of the box.

What is missing:
Yet there is one item that could be improved: Once a log file has been renamed (rotated) Traccar is required start writing into a new log file with the same name, so basically re-create the original (now empty) log file. Currently this can be achieved by restarting Traccar entirely but means an interruption of service and a potential loss of communication - especially on large systems.

So it is desired to have a functionality to send a signal to the running Traccar server which triggers the closing and re-creation of the log file while keeping the rest of the service running. Similar to how it is described here: log4js-node/log4js-node#343

[tananaev]

Can you use console logger and just pipe it to syslog or some other external logging system?

[twouters]

You don't have to restart the traccar service if you add the copytruncate option to the logrotate config.