Log rotation

Log produced by the API grow quickly and lead to big log files. You will need quickly to configure logrotate to create a new log file every day.

Store PID of zou processes

To create a folder on boot to store pid files add a RuntimeDirectory add a line before ExecStart in the unit file (/etc/systemd/system/zou.service):

RuntimeDirectory=zou

Add this to the ExecStart line to create the pid file for zou

-p /run/zou/zou.pid

For example:

ExecStart=/opt/zou/zouenv/bin/gunicorn -p /run/zou/zou.pid -c /etc/zou/gunicorn.py -b 127.0.0.1:5000 zou.app:app

Edit the zou-events unit file to create the pid file for zou-events
(/etc/systemd/system/zou-events.service):

-p /run/zou/zou-events.pid

PIDs are now stored in mentioned files.

Configure logrotate

We can now proceed to the Logrotate configuration. Logrotate is a Unix tool that will handle the log rotation for you. It just requires a configuration file to work properly.

Add this logrotate configuration (/etc/logrotate.d/zou):

/opt/zou/logs/gunicorn_access.log {
    daily
    missingok
    rotate 14
    notifempty
    nocompress
    size 100M
    create 644 zou zou
    postrotate
        kill -USR1 `cat /run/zou/zou.pid`
    endscript
}

/opt/zou/logs/gunicorn_error.log {
    daily
    missingok
    rotate 14
    nocompress
    size 100M
    notifempty
    create 644 zou zou
    postrotate
        kill -USR1 `cat /run/zou/zou.pid`
    endscript
}

/opt/zou/logs/gunicorn_events_access.log {
    daily
    missingok
    rotate 14
    nocompress
    size 100M
    notifempty
    create 644 zou zou
    postrotate
        kill -USR1 `cat /run/zou/zou-events.pid`
    endscript
}

/opt/zou/logs/gunicorn_events_error.log {
    daily
    missingok
    rotate 14
    nocompress
    size 100M
    notifempty
    create 644 zou zou
    postrotate
        kill -USR1 `cat /run/zou/zou-events.pid`
    endscript
}

It will create a new log file for each day, and keep only the last 14 files.

You can test the log rotation is set up correctly by running

logrotate /etc/logrotate.d/zou --debug

You're done with log rotation!