带有正则表达式的 Nginx 变量

Question

我有一个大约 40 多个节点服务器的 nginx 配置，所有这些都写成这样：

location /39/api {
    proxy_pass http://172.31.32.233:3138;
}

location /io39 {
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_http_version 1.1;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_pass http://172.31.32.233:3138;
}

location /40/api {
    proxy_pass http://172.31.32.233:3139;
}

location /io40 {
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_http_version 1.1;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_pass http://172.31.32.233:3139;
}

您可以看到目标节点端口随着 ID 进入 /io39 和 /39/api 路径而增加，我知道我可以使用正则表达式将数字捕获到 location 指令中，但是如何将变量增加为整数并将其用作代理的目标端口，这样我就可以为千端口编写一个唯一的指令？

谢谢！

Answer 1

虽然在 5.5 之前的 Perl 和 PHP 中有一个 evaluation 正则表达式修饰符，但据我所知，nginx 没有任何等效项，也没有正则表达式数学是可能的。 this 回答中描述的可能技术之一。例如，您可以通过这种方式添加 30000 之类的内容（我首先使用最长的 4 位正则表达式模式，因为正则表达式匹配位置是从第一个到最后一个进行检查）：

location ~ "^/(\d{4})/api" {
    set $port 3$1;
    proxy_pass http://172.31.32.233:$port;
}

location ~ "^/io(\d{4})" {
    set $port 3$1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_http_version 1.1;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_pass http://172.31.32.233:$port;
}

location ~ "^/(\d{3})/api" {
    set $port 30$1;
    proxy_pass http://172.31.32.233:$port;
}

location ~ "^/io(\d{3})" {
    set $port 30$1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_http_version 1.1;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_pass http://172.31.32.233:$port;
}

location ~ "^/(\d{2})/api" {
    set $port 300$1;
    proxy_pass http://172.31.32.233:$port;
}

location ~ "^/io(\d{2})" {
    set $port 300$1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_http_version 1.1;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_pass http://172.31.32.233:$port;
}

location ~ "^/(\d)/api" {
    set $port 3000$1;
    proxy_pass http://172.31.32.233:$port;
}

location ~ "^/io(\d)" {
    set $port 3000$1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_http_version 1.1;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_pass http://172.31.32.233:$port;
}

这将为/1/api 或/io1（以及/01/api 或/io01）提供端口号30001，为/2/api 或/io2 提供端口号30002，依此类推，最多为39999 /9999/api 或 /io9999 URI。

另一种方式是使用lua-nginx-module或OpenResty：

location ~ "^/(?<number>\d{1,4})/api" {
    set_by_lua_block $port { return ngx.var.number + 3099 }
    proxy_pass http://172.31.32.233:$port;
}

location ~ "^/io(?<number>\d{1,4})" {
    set_by_lua_block $port { return ngx.var.number + 3099 }
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_http_version 1.1;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_pass http://172.31.32.233:$port;
}