anonymized log format configuration for nginx

anonymized-nginx-log-format.conf

# Add this to /etc/nginx/nginx.conf in http {} block
map $remote_addr $ip_anonym1 {
 default 0.0.0;
 "~(?P<ip>(\d+)\.(\d+)\.(\d+))\.\d+" $ip;
 "~(?P<ip>[^:]+:[^:]+):" $ip;
}

map $remote_addr $ip_anonym2 {
 default .0;
 "~(?P<ip>(\d+)\.(\d+)\.(\d+))\.\d+" .0;
 "~(?P<ip>[^:]+:[^:]+):" ::;
}

map $ip_anonym1$ip_anonym2 $ip_anonymized {
 default 0.0.0.0;
 "~(?P<ip>.*)" $ip;
}

log_format anonymized '$ip_anonymized - $remote_user [$time_local] ' 
   '"$request" $status $body_bytes_sent ' 
   '"$http_referer" "$http_user_agent"';

### use it like that ###
# server {
# ......
# access_log  /var/log/nginx/access.log anonymized;
# ......
# }