Path-based Routing with HAProxy

blog20220822-01.cfg

frontend mysite
  bind :80

  # route to a backend based on path's prefix
  use_backend app-a if { path /a } || { path_beg /a/ }
  use_backend app-b if { path /b } || { path_beg /b/ }

backend app-a
  # strip the prefix '/a' off of the path
  http-request replace-path /a(/)?(.*) /\2
  server server1 127.0.0.1:8080 check maxconn 30

backend app-b
  # strip the prefix '/b' off of the path
  http-request replace-path /b(/)?(.*) /\2
  server server1 127.0.0.1:8081 check maxconn 30

blog20220822-02.cfg

use_backend app-a if { path /a } || { path_beg /a/ }
use_backend app-b if { path /b } || { path_beg /b/ }

blog20220822-03.cfg

use_backend app-a if { path /a /c /d } || { path_beg /a/ /c/ /d/ }

blog20220822-04.cfg

acl app-a-path path /a /c /d
acl app-a-path path_beg /a/ /c/ /d/
use_backend app-a if app-a-path

blog20220822-05.cfg

backend app-a
  http-request replace-path /a(/)?(.*) /\2
  server server1 127.0.0.1:8080 check maxconn 30

backend app-b
  http-request replace-path /b(/)?(.*) /\2
  server server1 127.0.0.1:8081 check maxconn 30