uWSGI logging not working if log file is removed

Question

My goal is rotating the logs generated by uWSGI, but when the original log file is deleted (after compression) it is not re-created again.

So I thought that the app needs a graceful restart of the master process after the file is deleted. I use this RESTART script:

/home/tester/uwsgi-18
--reload /var/run/uwsgi/my_app_tester/my_app_tester.pid

The app restart, but the log does not.

To get the logging work again I need to kill -2 the process and run the START script again, so another process number is generated and the logging works again.

Obviously I do not want such hard STOP just for rotating logs...

My app is built with Catalyst, the server runs Nginx and here it is the uWSGI START script:

/home/tester/uwsgi-18
--master
--daemonize /var/log/uwsgi/my_app_tester/log
--socket /tmp/uwsgi/my_app_tester/my_app_tester.socket
--processes 1
--psgi /home/tester/my_app/my_app.psgi
--pidfile /var/run/uwsgi/my_app_tester/my_app_tester.pid
--procname-master TESTER
-L

Is there another way to restart the app without loosing connections and logging?

Thank you in advance: Migue

Answer 1

You have various approaches:

1) copytruncate in the logrotate script, this will work reliably and without the help of uWSGI

2) uWSGI log rotation: --log-maxsize <bytes> will automatically rotate logs when a specific size is reached

3) classic logrotation + log reloading, just add --log-master and trigger log reloading with http://uwsgi-docs.readthedocs.org/en/latest/MasterFIFO.html

There are other approaches too (like triggering the log reopen when touching a files), but the previous one are the most common.