The task is to save to a log file all requests excluding ones with the 200 response from the NGINX.
Using such an approach with the map – you can do various things, for example – chose a location to be used based on a header value. Will add such an example later.
For now, we are interested in two NGINX abilities: the conditional logging to choose when need to save an event to a log file and the map to set a variable’s value based on other variables.
Contents
map
Add the $abnormal variable in the http {} block and set its value to 0 – if a response has 200 value or 1 – if not:
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
map $status $abnormal {
~^200 0;
default 1;
}
...
Conditional logging
Next in the server {} set condition to be used for the access.log using if: if the $abnormal variable’s value is zero – then log nothing, if 1 – to save this response to the log:
server {
charset utf-8;
listen 80 default_server;
server_name stage.example.com;
if ($http_x_forwarded_proto = 'http') {
return 301 https://stage.example.com$request_uri;
}
set $root_path /data/projects/frontend/web;
root $root_path;
index index.php;
error_log /var/log/nginx/stage.example.com-error.log;
access_log /var/log/nginx/stage.example.com-access.log combined if=$abnormal;
...
Check it:
[simterm]
127.0.0.1 - - [15/Mar/2019:14:51:37 +0200] "GET /nginx_status HTTP/1.1" 404 153 "-" "Go-http-client/1.1" 127.0.0.1 - - [15/Mar/2019:14:51:52 +0200] "GET /nginx_status HTTP/1.1" 404 153 "-" "Go-http-client/1.1"
[/simterm]
Done.
