# Debugging running Nginx config – hackanooga

July 16, 2024

# Debugging running Nginx config

I was recently working on project where a client had cPanel/WHM with Nginx and Apache. They had a large number of sites managed by Nginx with a large number of includes. I created a custom config to override a location block and needed to be certain that my changes where actually being picked up. Anytime I make changes to an Nginx config, I try to be vigilant about running:

    nginx -t

to test my configuration and ensure I don’t have any syntax errors. I was looking for an easy way to view the actual compiled config and found the `-T` flag which will test the configuration and dump it to standard out. This is pretty handy if you have a large number of includes in various locations. Here is an example from a fresh Nginx Docker container:

    root@2771f302dc98:/# nginx -T
    nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
    nginx: configuration file /etc/nginx/nginx.conf test is successful
    # configuration file /etc/nginx/nginx.conf:

    user  nginx;
    worker_processes  auto;

    error_log  /var/log/nginx/error.log notice;
    pid        /var/run/nginx.pid;

    events {
        worker_connections  1024;
    }

    http {
        include       /etc/nginx/mime.types;
        default_type  application/octet-stream;

        log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                          '$status $body_bytes_sent "$http_referer" '
                          '"$http_user_agent" "$http_x_forwarded_for"';

        access_log  /var/log/nginx/access.log  main;

        sendfile        on;
        #tcp_nopush     on;

        keepalive_timeout  65;

        #gzip  on;

        include /etc/nginx/conf.d/*.conf;
    }

    # configuration file /etc/nginx/mime.types:

    types {
        text/html                                        html htm shtml;
        text/css                                         css;
        text/xml                                         xml;
        image/gif                                        gif;
        image/jpeg                                       jpeg jpg;
        application/javascript                           js;
        application/atom+xml                             atom;
        application/rss+xml                              rss;

        text/mathml                                      mml;
        text/plain                                       txt;
        text/vnd.sun.j2me.app-descriptor                 jad;
        text/vnd.wap.wml                                 wml;
        text/x-component                                 htc;

        image/avif                                       avif;
        image/png                                        png;
        image/svg+xml                                    svg svgz;
        image/tiff                                       tif tiff;
        image/vnd.wap.wbmp                               wbmp;
        image/webp                                       webp;
        image/x-icon                                     ico;
        image/x-jng                                      jng;
        image/x-ms-bmp                                   bmp;

        font/woff                                        woff;
        font/woff2                                       woff2;

        application/java-archive                         jar war ear;
        application/json                                 json;
        application/mac-binhex40                         hqx;
        application/msword                               doc;
        application/pdf                                  pdf;
        application/postscript                           ps eps ai;
        application/rtf                                  rtf;
        application/vnd.apple.mpegurl                    m3u8;
        application/vnd.google-earth.kml+xml             kml;
        application/vnd.google-earth.kmz                 kmz;
        application/vnd.ms-excel                         xls;
        application/vnd.ms-fontobject                    eot;
        application/vnd.ms-powerpoint                    ppt;
        application/vnd.oasis.opendocument.graphics      odg;
        application/vnd.oasis.opendocument.presentation  odp;
        application/vnd.oasis.opendocument.spreadsheet   ods;
        application/vnd.oasis.opendocument.text          odt;
        application/vnd.openxmlformats-officedocument.presentationml.presentation
                                                         pptx;
        application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
                                                         xlsx;
        application/vnd.openxmlformats-officedocument.wordprocessingml.document
                                                         docx;
        application/vnd.wap.wmlc                         wmlc;
        application/wasm                                 wasm;
        application/x-7z-compressed                      7z;
        application/x-cocoa                              cco;
        application/x-java-archive-diff                  jardiff;
        application/x-java-jnlp-file                     jnlp;
        application/x-makeself                           run;
        application/x-perl                               pl pm;
        application/x-pilot                              prc pdb;
        application/x-rar-compressed                     rar;
        application/x-redhat-package-manager             rpm;
        application/x-sea                                sea;
        application/x-shockwave-flash                    swf;
        application/x-stuffit                            sit;
        application/x-tcl                                tcl tk;
        application/x-x509-ca-cert                       der pem crt;
        application/x-xpinstall                          xpi;
        application/xhtml+xml                            xhtml;
        application/xspf+xml                             xspf;
        application/zip                                  zip;

        application/octet-stream                         bin exe dll;
        application/octet-stream                         deb;
        application/octet-stream                         dmg;
        application/octet-stream                         iso img;
        application/octet-stream                         msi msp msm;

        audio/midi                                       mid midi kar;
        audio/mpeg                                       mp3;
        audio/ogg                                        ogg;
        audio/x-m4a                                      m4a;
        audio/x-realaudio                                ra;

        video/3gpp                                       3gpp 3gp;
        video/mp2t                                       ts;
        video/mp4                                        mp4;
        video/mpeg                                       mpeg mpg;
        video/quicktime                                  mov;
        video/webm                                       webm;
        video/x-flv                                      flv;
        video/x-m4v                                      m4v;
        video/x-mng                                      mng;
        video/x-ms-asf                                   asx asf;
        video/x-ms-wmv                                   wmv;
        video/x-msvideo                                  avi;
    }

    # configuration file /etc/nginx/conf.d/default.conf:
    server {
        listen       80;
        server_name  localhost;

        #access_log  /var/log/nginx/host.access.log  main;

        location / {
            root   /usr/share/nginx/html;
            index  index.html index.htm;
        }

        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   /usr/share/nginx/html;
        }

        # proxy the PHP scripts to Apache listening on 127.0.0.1:80
        #
        #location ~ \.php$ {
        #    proxy_pass   http://127.0.0.1;
        #}

        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        #location ~ \.php$ {
        #    root           html;
        #    fastcgi_pass   127.0.0.1:9000;
        #    fastcgi_index  index.php;
        #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
        #    include        fastcgi_params;
        #}

        # deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #
        #location ~ /\.ht {
        #    deny  all;
        #}
    }

As you can see from the output above, we get all of the various Nginx config files in use printed to the console, perfect for `grepping` or searching/filtering with other tools.

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