bash function to perform a sanity check on nginx files - bash

Question

I am trying to write a function which performs a sanity check of files before I move them into /etc/nginx/site-available.
There are located in my home directory and are modified regularly.
The only modification done in those files is to add a server_name.
They look like:
server {
listen 80;
server_name domain.com;
server_name www.domain.com;
server_name mynsite1.com;
server_name www.mysite1.com;
server_name mysite2.com;
server_name www.mysite2.com;
server_name mysite3.com;
server_name www.mysite3.com;
server_name mysite4.com;
server_name www.mysite4.com;
access_log /var/log/nginx/domain.com-access.log main;
error_log /var/log/nginx/domain.com-error.log warn;
root /var/www/docroot;
index index.php index.html index.htm;
location / {
try_files $uri /app_dev.php;
}
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
location ~ \.php$ {
fastcgi_split_path_info ^(.+\.php)(/.+)$;
# NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
location ~ /\.ht {
deny all;
}
}
Here is the function I have right now:
verify_nginx()
{
if [ ! -s "$file1" ]; then
echo "-> File \"$file1\" is empty or do not exist" | ts
exit 1
elif [ ! -s "$file2" ]; then
echo "-> File \"$file2\" is empty or do not exist" | ts
exit 1
fi
}
I would also like to add nginx -t -c /homedir/file1 in the function but I get the following error:
nginx: [emerg] "server" directive is not allowed here in /homedir/file:1
nginx: configuration file /homedir/file test failed
Indeed nginx -c is expecting nginx.conf which does not include my files in my homedir.
I could put my files in /etc/nginx/site-available which is included in nginx.conf but I want to perform the sanity check before I move the files to the correct location.
My questions:
Is there a way to test the configuration file located somewhere else than in /etc/nginx/site-available using nginx?
What kind of sanity checks should be performed on nginx files?

Answer 1

The files you're trying to sanity-check are not nginx config files, therefore (understandably) nginx -t says they're invalid. The -c flag expects "an alternative configuration file", not a single server block. server blocks live inside an http block.
If you want to run nginx -t you need to pass it a proper config file, which would include the files you're attempting to modify. You could, as Etan Reisner suggests, simply write a dummy nginx.conf that includes your files, something like this might work (I'm not on a machine with nginx installed atm, so you may have to add a few more stub directives):
http {
include path/to/files/*;
}
Then you can run nginx -t -c dummy_nginx.conf.
This has a problem though; you could still have any number of errors that are only revealed when your real config file is loaded.
Instead, you can verify your real config file with your changes before they're loaded by simply calling nginx -t before you reload; you could wrap this in a bash function if you wanted:
safe_reload() {
nginx -t &&
service nginx reload # only runs if nginx -t succeeds
}
You should also have some sort of backup or restore mechanism. This could be as simple as copying your old config files to parallel *.bak files, but much more pleasant is using a VCS like Mercurial or Git. You check in each iteration of your configs that succeed, and then you can easily revert to the previous known good configuration if anything goes wrong.