cgi_stderr

The cgi_stderr directive specifies the level of logging for standard error output generated by the CGI scripts executed by NGINX. This option is useful when you want to control the verbosity of error logs from CGI scripts. It accepts one of several logging levels (e.g., off, stderr, or a specific log level such as info, warn, error, crit, etc.). When set to stderr, the errors will be directed to the standard error stream, which is typically logged by the NGINX process. Customizing the logging level allows administrators to filter out less critical information and only capture logs that are pertinent to debugging or monitoring application behavior.

The directive can be applied within the server or location contexts of the NGINX configuration file. The default setting for cgi_stderr is warn, meaning that any errors at or above the warning level will be logged. When setting a custom log level, you should be cautious, as excessively verbose logging might lead to large log files and make it harder to identify important issues. The values and behavior of this directive can influence how well application errors are captured and how easy or difficult it is to troubleshoot those issues in production environments.