Support full spectrum of HAProxy rules

[tamalsaha]

Request:
https://www.haproxy.com/doc/aloha/7.0/haproxy/http_rewriting.html#rewriting-http-requests

Response:
https://www.haproxy.com/doc/aloha/7.0/haproxy/http_rewriting.html#rewriting-http-responses

Health checks:
https://www.haproxy.com/doc/aloha/7.0/haproxy/healthchecks.html

[tamalsaha]

From @skuda

I needed to add another haproxy rule to get phpmyadmin fully working

this is the final setup of one backend

   reqrep ^(GET|POST|HEAD)\ /1/(.*)     \1\ /\2

   acl hdr_location res.hdr(Location) -m found
   rspirep ^Location:\ (https?://phpmyadmin.local(:[0-9]+)?)?(/.*) Location:\ /1/ if hdr_location

   server server-10.200.65.19 10.200.65.19:80```

This way I got the rewrites needed, this is something that is accomplish in Apache mod_proxy with "ProxyPassReverse"

you can get the details here https://www.haproxy.com/blog/howto-write-apache-proxypass-rules-in-haproxy/ (edited)

without that I was able to see the home but every submit button was broken, because it directed to phpmyadmin.local, not phpmyadmin.local/1

[tamalsaha]

• haproxyRule or rawRule key.
• Array of strings
• Prefix auto generated acls with __ prefix

[sadlil]

If we use haproxyRule / backendRules then there is option that we can remove our current existing
headerRule and rewriteRule. But removing those won't be backward compatible. So should we mark those deprecated for now and introduce the new backendRule along side them? @tamalsaha

[tamalsaha]

We will keep the old things as is. When we rewrite everything for the new TPR in 1.7, we will review these things. I think there is a good case to be made to have direct support for common HTTP rewrite rules.

[tamalsaha]

@skuda, We have added new BackendRule that can used to add any custom acl rules for a backend. This can be used to add response headers. See docs here: https://github.com/appscode/voyager/blob/master/docs/user-guide/component/ingress/backend-rule.md

[skuda]

Tested, working fine, thanks!!