I've been experimenting a bit with error logging in php-fpm and nginx since I couldn't find any good explanation on the web. Most guides said I should change catch_workers_output to yes if I want to send errors from php5-fpm back to nginx. However, during my experiments I've found that even when catch_workers_output is set to no, errors are still being logged properly by nginx.
Here's my virtualhost config:
server { server_name domain.com; return 301 http://www.domain.com$request_uri; access_log off; } server { listen 80; listen [::]:80; root /home/websites/domain.com; index index.php index.html index.htm; error_log /home/websites/logs/domain.com/error.log warn; access_log /home/websites/logs/domain.com/access.log; #switch on gzip gzip on; gzip_min_length 1100; gzip_buffers 10 32k; gzip_types text/plain application/x-javascript text/xml text/css; gzip_vary on; location / { try_files $uri $uri/ /index.php?q=$uri&$args; } location ~* .(gif|jpg|jpeg|png|css|js|ico)$ { expires 30d; access_log off; } error_page 404 /404.html; location ~ \.php$ { fastcgi_split_path_info ^(.+\.php)(/.+)$; # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini # With php5-cgi alone: # With php5-fpm: fastcgi_pass unix:/var/run/php5-fpm.sock; fastcgi_index index.php; include fastcgi_params; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; } # deny access to .htaccess files, if Apache's document root # concurs with nginx's one location ~ /\.ht { deny all; } } Here are my findings:
Exp 1 poolconf: ; catch_workers_output = no (commented out) php_admin_value[error_log] = /var/log/fpm-php.www.log php_admin_flag[log_errors] = on ; php_flag[display_errors] = 0 result: errors not shown in browser error written in /var/log/fpm-php.www.log error not written in virtualhost error-log in nginx errors not displayed in stderr when running php5-fpm non-daemonized Exp 2 poolconf: catch_workers_output = yes php_admin_value[error_log] = /var/log/fpm-php.www.log php_admin_flag[log_errors] = on php_flag[display_errors] = 0 results: no error in browser error written in /var/log/fpm-php.www.log error not written to virtualhost error-log by nginx errors not displayed in stderr when running php5-fpm non-daemonized Exp 3 poolconf: catch_workers_output = yes ; php_admin_value[error_log] = /var/log/fpm-php.www.log ; php_admin_flag[log_errors] = on php_flag[display_errors] = 0 results: no errors in browser error NOT written in /var/log/fpm-php.www.log error WRITTEN to virtualhost error-log by nginx errors DISPLAYED in stderr when running php5-fpm non-daemonized Exp 4 poolconf: ; catch_workers_output = no (commented out) ; php_admin_value[error_log] = /var/log/fpm-php.www.log ; php_admin_flag[log_errors] = on php_flag[display_errors] = 0 results: no errors in browser error NOT written in /var/log/fpm-php.www.log error WRITTEN to virtualhost error-log by nginx errors NOT displayed in stderr when running php5-fpm non-daemonized My question is how does PHP5-FPM send error logs to nginx even if there's no stderr output (when catch_workers_output=no) from php-fpm? I cannot find it documented anywhere.
