Nginx locations: Exempt certain location from maintenance mode - symfony

Question

I have a Symfony 3.4 application running on nginx and a maintenance mode is implemented the following way in nginx:
location / {
# try to serve file directly, fallback to app.php
try_files $uri /app.php$is_args$args;
}
location ~ ^/(app)\.php(/|$) {
if (-f "/var/www/mysite.com/web/maintenance.html") {
return 503;
}
fastcgi_pass unix:/run/php/php7.0-fpm.sock;
fastcgi_split_path_info ^(.+\.php)(/.*)$;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
fastcgi_param DOCUMENT_ROOT $realpath_root;
}
error_page 503 #maintenance;
location #maintenance {
rewrite ^(.*)$ /maintenance.html break;
}
I would like to exempt a certain location from maintenance mode, so that this location keeps being served by the Symfony application. So that requests to mysite.com/still/available/route are not redirected to the maintenance page.
How can that be done?

Answer 1

I found the answer, actually, it was quite obvious. One just needs to put the "if" into the root location block (/) and add another location block with the path that is supposed to remain accessible during maintenance mode. There, of course, must not appear that if-clause:
location / {
# try to serve file directly, fallback to app.php
if (-f "/var/www/mysite.com/web/maintenance.html") {
return 503;
}
try_files $uri /app.php$is_args$args;
}
location /still/available/route {
try_files $uri /app.php$is_args$args;
}
location ~ ^/(app)\.php(/|$) {
fastcgi_pass unix:/run/php/php7.0-fpm.sock;
fastcgi_split_path_info ^(.+\.php)(/.*)$;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
fastcgi_param DOCUMENT_ROOT $realpath_root;
}
error_page 503 #maintenance;
location #maintenance {
rewrite ^(.*)$ /maintenance.html break;
}