How do you conditionally include files in Nginx vhost?

include does its thing during server start - runtime variables like $host can't be used, nor is it able to be used in an if context, as you found out.

You'd need to split up the server blocks for different hosts. Sorry!

Well, this is rather old, but anyway, I found a work-around.

I have a setup with vhosts configured in this style:

/etc/nginx/sites-enabled/site.com.conf

Instead of checking if the file exists (which isn't possible), I simply do:

include /etc/nginx/sites-customizations/site.com.*.conf

This way I can simply create a file in the sites-customizations-folder, which by my convention, is named the same as the main configuration. The * works pretty much like the if, as it doesn't break if there is no extra configuration files. If you like, this also enables you to add multiple extra configurations in separate files.

I take advantage of the glob() function pattern expansion, which is used by nginx in the include directive, and works well on my Debian servers.

In your case, try to replace this line:

include /path/www/$host/nginx.conf;

with this one:

include /path/www/<hostname>/nginx[.]conf;

it's a file mask that matches only one file, and won't make nginx complain if the file does not exist. However variables are not allowed in include directives, so you must supply a fixed value in <hostname>. We had to create a script that generates individual .conf files (one per vhost).

Edit

As Gerald Schneider pointed out, I was suggesting to keep $host in the replacement, which is not allowed. I've changed the suggestion above.

I know this is old but solution might help someone looking for an answer like I did.

I had a bunch of redirects that I needed to include for a specific host only and while include is not allowed in the if directive, I ended up adding the if inside the file I was including...

So I have an include /etc/nginx/conf.d/redirects and inside that file I have:

if ($host = "www.example.com") {
    # Some conf or redirects for this site only.
}