The access-log-exporter works with various web servers, including Nginx and Apache. This guide provides instructions for setting up the exporter with these servers.

By default, the exporter listens on port 8514/udp for incoming log messages in RFC3164 format. We recommend using UDP for sending logs to the exporter.

access-log-exporter exclusively supports RFC3164 format for incoming logs. Nginx and Apache2, among others, support this format.

The log format must use tab separation (\t) to avoid parsing issues. The exporter does not support JSON or other formats.

Nginx can generate access logs compatible with access-log-exporter. This requires defining a custom log format in the Nginx configuration file.

Common locations for this file include /etc/nginx/nginx.conf or /etc/nginx/conf.d/default.conf, depending on the operating system. You can also create an additional configuration file in the /etc/nginx/conf.d/ directory.

access-log-exporter includes multiple presets. We recommend the simple or simple_upstream presets for most use cases. The simple preset logs the request method, status code, response time, and request/response sizes. The simple_upstream preset additionally logs upstream response times and status codes.

To configure Nginx, add the following lines to the configuration file.

# Use only one of the presets below, depending on your needs.
# simple preset
log_format accesslog_exporter '$http_host\t$request_method\t$status\t$request_completion\t$request_time\t$request_length\t$bytes_sent';
access_log syslog:server=127.0.0.1:8514 accesslog_exporter,nohostname;

# simple_upstream preset
log_format accesslog_exporter '$http_host\t$request_method\t$status\t$request_completion\t$request_time\t$request_length\t$bytes_sent\t$upstream_addr\t$upstream_connect_time\t$upstream_header_time\t$upstream_response_time';
access_log syslog:server=127.0.0.1:8514 accesslog_exporter,nohostname;

References:

• Nginx Documentation: Logging
• Nginx Documentation: Syslog

To exclude specific requests from logging by access-log-exporter, use the if directive in Nginx. For example, to exclude requests to /health and /metrics, add the following lines:

# Exclude specific requests from logging
map $request_uri $loggable {
    default 1;
    ~^/health 0;
    ~^/metrics 0;
}

# Use only one of the presets below, depending on your needs.
# simple preset with exclusion
log_format accesslog_exporter '$http_host\t$request_method\t$status\t$request_completion\t$request_time\t$request_length\t$bytes_sent';
access_log syslog:server=127.0.0.1:8514 accesslog_exporter,nohostname if=$loggable;

# simple_upstream preset with exclusion
log_format accesslog_exporter '$http_host\t$request_method\t$status\t$request_completion\t$request_time\t$request_length\t$bytes_sent\t$upstream_addr\t$upstream_connect_time\t$upstream_header_time\t$upstream_response_time';
access_log syslog:server=127.0.0.1:8514 accesslog_exporter,nohostname if=$loggable;

Apache can generate access logs compatible with access-log-exporter. This requires the mod_log_config module to define a custom log format. Recording incoming and outgoing request sizes requires the mod_logio module.

Add the following lines to the Apache configuration file. Common locations for this file include /etc/apache2/apache2.conf and /etc/httpd/conf/httpd.conf, depending on the operating system.

Adjust the binary path for the logger command if your system uses a different location.

# Configuration for the access-log-exporter
LogFormat "%v\t%m\t%>s\tOK\t%{ms}T\t%I\t%O" accesslog_exporter
CustomLog "|/usr/bin/logger --rfc3164 --server 127.0.0.1 --port 8514 --udp" accesslog_exporter

Apache does not natively log information about upstream servers. To track upstream response times or status codes, integrate additional modules or external tools.