4

I'm trying to set up an Nginx, where I want to add two numbers together.

server {
        server_name "~^pr-(\d*).review-apps.example.com$";
        
        location / {
            set $port 50000+$1;
            proxy_pass "http://localhost:$port/test";
        }
    }

But this doesn't work . (Result is in string. For example "50000+125")

How can I add two numbers in nginx.conf? Is it even possible?

Jetam
  • 78
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2 Answers2

2

If you use fixed length numbers, for example only three digits, for this particular case you can use string concatenation instead of adding numbers:

server {
    server_name "~^pr-(\d{3}).review-apps.example.com$";
        
    location / {
        set $port 50$1;
        proxy_pass "http://localhost:$port/test";
    }
}

This will give you exactly 50145 for the pr-125.review-apps.example.com hostname.

For variable count of port number digits you can use named regex capture group:

server {
    server_name  "~^pr-(?<pr1>\d).review-apps.example.com$"
                 "~^pr-(?<pr2>\d{2}).review-apps.example.com$"
                 "~^pr-(?<pr3>\d{3}).review-apps.example.com$";

    location / {
        if ($pr1) { set $port 5000$pr1; }
        if ($pr2) { set $port 500$pr2; }
        if ($pr3) { set $port 50$pr3; }
        proxy_pass "http://localhost:$port/test";
    }
}
Ivan Shatsky
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0

No, it is not possible to use math with standard modules. There might be a chance with lua module but you probably shouldn't as NGINX wasn't meant to be used like that. It is like using a screwdriver to hammer a nail - it is possible that you succeed but it is also possible that you poke out an eye along the way.

I suggest you reconsider the design of your application, perhaps there is a better/commonly used way to achieve what you want.

anemyte
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