I'm trying to use a rewrite in nginx-openresty following a simple example:

location /test 
{
   rewrite_by_lua_block { ngx.req.set_uri("/authgp") } 
}

location /authgp {
    proxy_pass http://authwf.org:9001/realms/gp/protocol/openid-connect/token;
}

When I invoke /test, nginx try to find a file named: [error] 35890#5234410: *1 open() "/opt/ho.../auth instead of forwarding to location /authgp as the example says.

How can I tell nginx-openresty not to try to resolve a file but a location?

Thanks! Fernando

TL;DR: use ngx.req.set_uri("/authgp", true) (add the second true argument)

Explanation

https://github.com/openresty/lua-nginx-module?tab=readme-ov-file#ngxreqset_uri

syntax: ngx.req.set_uri(uri, jump?, binary?)

The optional boolean jump argument can trigger location rematch (or location jump) as ngx_http_rewrite_module's rewrite directive[...]

For example, the following Nginx config snippet

rewrite ^ /foo last;

can be coded in Lua like this:

ngx.req.set_uri("/foo", true)

Similarly, Nginx config

rewrite ^ /foo break;

can be coded in Lua as

ngx.req.set_uri("/foo", false)

or equivalently,

ngx.req.set_uri("/foo")

https://nginx.org/en/docs/http/ngx_http_rewrite_module.html#rewrite

last

stops processing the current set of ngx_http_rewrite_module directives and starts a search for a new location matching the changed URI;

break

stops processing the current set of ngx_http_rewrite_module directives as with the break directive; (Emphasis added)

https://nginx.org/en/docs/http/ngx_http_rewrite_module.html#break

Syntax: break;

Stops processing the current set of ngx_http_rewrite_module directives.

If a directive is specified inside the location, further processing of the request continues in this location. (Emphasis added)

Since you use set_uri inside the location block (location /test), with jump = false (the default value) “further processing of the request continues in this location.” (this location = the location /test block).