PHP-FPM logging

PHP-FPM basic model

• Master process — manages the PHP-FPM pool and maintains the main error_log.
• Worker processes — handle Passwork FastCGI requests and produce PHP errors or warnings.

catch_workers_output

Redirects worker output (stdout and stderr) to the master process stream or a log file. The destination is defined by the error_log parameter in the php-fpm.conf configuration file.

Possible values:

• yes — worker stdout and stderr are redirected to the stream or file defined in error_log;
• no (default) — worker output is redirected to /dev/null (per FastCGI specification).

This setting is commonly used in containerized environments to collect and forward events through stdout/stderr via error_log.

error_log

The error_log parameter value (in php-fpm.conf) defines where PHP-FPM writes logs:

• file (for example, /var/log/php-fpm.log);
• syslog for forwarding to syslogd;
• stream (for example, /dev/stderr).

If error_log is directed to a stream (for example, /dev/stderr or /proc/self/fd/2), captured worker output is also sent to the container log stream.

Activity log in Passwork

For Activity log, the ACTIVITY_LOG_OUTPUT parameter defines the output channel:

• syslog — writes action events via syslog;
• stdout — writes action events to the PHP-FPM stream.

LLM version