NGINX - Regex into locations.conf doesn't work - regex

Question

I have an issue into the configuration of my nginx proxy.
I just try to use regex has it is defined here: https://underthehood.meltwater.com/blog/2017/12/12/lightweight-tests-for-your-nginx-api-gateway/
But nothing works. My server won't start if it is any regex into the path.
I tried:
location ~ ^/tesla/(?<id>.*)$ {
proxy_pass http://localhost:8081/;
proxy_set_header Host $host;
}
or
location ~ ^/tesla/test/ {
proxy_pass http://localhost:8081/;
proxy_set_header Host $host;
}
or
location ~* ^/tesla/test/ {
proxy_pass http://localhost:8081/;
proxy_set_header Host $host;
}
Nothing work. My final aim is to extract a value from the url and do the following thing:
location ~* ^/(<version>.*)/test/ {
proxy_pass http://localhost:8081/;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-Prefix $version;
}
UPDATE (SOLVED)
I finally succeed thanks to Richard.
Here is the complete code:
location ~* ^/api/(?<version>.*)/(?<service>.*)(/.*/.*)$ {
proxy_pass http://$service.localnetwork:8080$3;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Prefix /api/$version/$service;
proxy_set_header msvc_name $service;
proxy_set_header msvc_version $version;
}

Answer 1

You can't use a proxy_pass with a static URI within a regular expression location block, it will throw an error - see your Nginx error log. See this document for details.
However, you can construct the URI to send upstream by appending variables to the proxy_pass statement. In your case, you could capture the remainder of the URI in the same regular expression.
For example:
location ~* ^/([^/]+)/test(/.*)$ {
proxy_pass http://localhost:8081$2;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-Prefix $1;
}