Syslog NG config for Turris Omnia which saves important parts of the logs to NAS. Date is also unified to a single timezone for all messages.

syslog-ng.conf

@version:3.19

options {
        chain_hostnames(no);
        flush_lines(0);
        stats_freq(0);
        flush_lines(0);
        log_msg_size(65536);
};

source src {
        internal();
        unix-dgram("/dev/log" flags("expect-hostname"));
};

source kernel {
        file("/proc/kmsg" program_override("kernel"));
};

filter f_turris_iptables {
        not match(".*turris[^:]*: .*" value(MESSAGE) type("pcre")) or not level(debug);
};

filter f_not_mountd_error {
    not match(".*could not find a serial number for the device sda.*" value(MESSAGE));
};

filter f_not_odhcp6 {
    not match(".*Failed to send DHCPV6 message to ff02::1:2.*" value(MESSAGE));
};

filter f_not_odhcpd {
    not match(".*A default route is present but there is no public prefix.*" value(MESSAGE));
};

filter f_not_odhcp6_rs {
    not match(".*Failed to send RS .Permission denied..*" value(MESSAGE));
};

filter f_not_nikola_info {
    not program("nikola") or not level(info);
};

filter f_not_cron {
    not program("cron");
};

filter f_not_debug {
    not level(debug);
};

filter f_not_ucollect_info {
        not program("ucollect") or not level(info);
};

filter f_not_kresd_info {
        not program("kresd") or not level(info);
};

filter f_not_nethist_info {
        not program("nethist") or not level(info);
};

filter f_not_firewall_rules {
        not program("turris-firewall-rules") or not level(info);
};

destination messages {
        file("/var/log/messages" suppress(5) template("${R_YEAR}-${R_MONTH}-${R_DAY} ${R_HOUR}:${R_MIN}:${R_SEC} ${PRIORITY} ${PROGRAM}[${PID}]: ${MSGONLY}\n") log_fifo_size(256));
};

destination nas {
        file("/mnt/nas/data/omnia-logs/${R_YEAR}/${R_MONTH}/messages-${R_YEAR}${R_MONTH}${R_DAY}.log" create-dirs(yes) dir-owner(root) owner(root) dir-perm(0755) perm(0755) suppress(5) template("${R_HOUR}:${R_MIN}:${R_SEC} ${PRIORITY} ${PROGRAM}[${PID}]: ${MSGONLY}\n") log_fifo_size(256));
};

log {
        source(src);
        source(kernel);
        filter(f_turris_iptables);
        filter(f_not_mountd_error);
        filter(f_not_odhcp6);
        filter(f_not_odhcpd);
        destination(messages);
};

log {
        source(src);
        source(kernel);
        filter(f_turris_iptables);
        filter(f_not_mountd_error);
        filter(f_not_cron);
        filter(f_not_odhcp6);
        filter(f_not_odhcpd);
        filter(f_not_nikola_info);
        filter(f_not_debug);
        filter(f_not_odhcp6_rs);
        filter(f_not_ucollect_info);
        filter(f_not_kresd_info);
        filter(f_not_nethist_info);
        filter(f_not_firewall_rules);
        destination(nas);
};
@include "/etc/syslog-ng.d/"