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<div>Hello nginx developers,<br>
<br>
Background: Our custom C++ module for nginx 1.11.4 uses subrequests to perform REST calls to our server during the course of processing incoming proxy requests. The subrequest / server URL is dynamic and varies by request e.g. <host1>.domain.foo, <host2>.domain.foo,
etc. There may be thousands of variations of host. As best we can tell, subrequests require explicit configuration in nginx.conf, where the host / URL is hard-coded. We'd rather not add thousands of config sections, which bloat the configuration and require
constant maintenance.<br>
<br>
Is there a way to configure nginx to proxy a large number of hosts, where the specific host is determined dynamically at runtime?<br>
<br>
We are basing our development on these sample resources: http://nginx.org/en/docs/http/ngx_http_auth_request_module.html or https://github.com/openresty/echo-nginx-module. Configuration for those modules hard-codes a small number of known locations for upstream
servers, e.g. auth request module (additional authentication servers would require additional location blocks):<br>
<br>
location /private/ {<br>
auth_request /auth;<br>
...<br>
}<br>
<br>
location = /auth {<br>
proxy_pass http://authserver<br>
...<br>
<br>
The first alternative approach we’ve come up with is to set an HTTP header in the subrequest containing the target URL (x_our_proxy_url=http://host1.domain.foo/...), target the subrequest at a static /ourproxy location, and in nginx.conf pass the URL from the
header to proxy_pass:<br>
<br>
location /ourproxy {<br>
proxy_pass $http_x_our_proxy_url;<br>
}<br>
<br>
While this works, it seems somewhat ad-hoc, and we’re wondering if there are better options for a subrequest to target arbitrary hosts. Note that use of third-party modules such as OpenResty is not really an option at this time, as we are strictly a C++ module.<br>
<br>
Thanks<br>
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<p>-- <br>
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<p>CG Development<br>
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