Nginx php-fpm 504 gateway error - php

Question

After hours of searching and debugging I give up!
There are thousands of questions and articles about long running PHP processes but non of them solved my issue.
I have a PHP script with the following codes:
$cur = 0;
// Second, loop for $timeout seconds checking if process is running
while( $cur < 31 ) {
sleep(1);
$cur += 1;
echo "\n ---- $cur ------ \n";
}
It is simply intended to run for 31 seconds.
I have a Nginx, PHP configured as fastcgi in debian server.
I set
max_execution_time = 600
In
/etc/php5/fpm/php.ini
I even set it in
/etc/php5/cli/php.ini
Also set
request_terminate_timeout = 600
in
/etc/php5/fpm/pool.d/www.conf
I also made these changes in nginx.conf http section
client_header_timeout 600;
client_body_timeout 600;
send_timeout 600;
fastcgi_read_timeout 600;
fastcgi_send_timeout 600;
client_max_body_size 600;
fastcgi_buffers 8 128k;
fastcgi_buffer_size 128k;
And put the directives inside server section. and these directives inside location section of nginx configuration
send_timeout 600;
fastcgi_read_timeout 600;
fastcgi_send_timeout 600;
client_max_body_size 600;
fastcgi_buffers 8 128k;
fastcgi_buffer_size 128k;
But I still encounter the Gateway Timeout error in the browser!
(And Yes! I restarted php-fpm and nginx thousands of times)
Do you guys have any idea?

Answer 1

Please don't take my answer as an insult but, did you make sure that your web server is on and did you try accessing another page of the site?

Answer 2

After seeing this answer, I tend to believe the situation is a s follows: nginx is trying to fill its FastCGI buffer (which is enabled by default) while your script is taking too long to return the first byte, resulting into the timeout. Provided I am correct, there are two things you need to do in order to resolve this:
Switch fastcgi_buffering to off
alter your script so that flush() and ob_flush() are called after each iteration:
while( $cur < 31 ) {
++$cur;
echo "\n ---- $cur ------ \n";
flush();
ob_flush();
sleep(1);
}
hth

Answer 3

I believe that you need to include the proxy_read_timeout directive in your Nginx configuration file. My own configuration file looks like this:
server {
proxy_read_timeout 300s;
...
}
You'll note that that is in my server block, however this directive is also valid inside of the http and location blocks as well.
*Edit to add that this is because Nginx proxies requests to the PHP-FPM server; the directives you attempted to use are only valid for content that is being served by Nginx itself, and not being proxied.