Logrotate

There is also automatic log rotation implemented in /etc/logrotate.d/suricata

/var/log/suricata/eve.json {
       daily
       rotate 30
       olddir /var/log/suricata/StatsByDate/
       compress
       missingok
       notifempty
       dateext
       postrotate
           /bin/kill -HUP $(cat /var/run/suricata.pid)
           /bin/kill -HUP $(cat /var/run/logstash.pid)
       endscript
}

# to see status
# cat /var/lib/logrotate/status
# to manually test -
# logrotate --force /etc/logrotate.d/suricata

That would logrotate eve.json daily and would keep max 30 days old logs.You can use the example above for any other log file you would like to logrotate. More info about logrotate.