fix: include PROXY health check in draining

jobs/haproxy/templates/drain.erb

@@ -46,6 +46,9 @@ haproxy_master_pid=$(pgrep -P "$pid" -x haproxy)
 
 <%- if p("ha_proxy.enable_health_check_http") -%>
 echo "disable frontend health_check_http_url" | /usr/local/bin/socat stdio unix-connect:${sockfile}
+<%- if p("ha_proxy.expect_proxy_cidrs", []).size > 0 -%>
+echo "disable frontend health_check_http_url_proxy_protocol" | /usr/local/bin/socat stdio unix-connect:${sockfile}
+<%- end -%>
 echo "$(date): triggering grace period for process ${haproxy_master_pid}" >> ${logfile}
 sleep <%= p("ha_proxy.drain_frontend_grace_time") %>
 <%- end -%>

spec/haproxy/templates/drain_spec.rb

@@ -31,6 +31,23 @@
           expect(drain).not_to include('drain is disabled')
           expect(drain).to include('socat')
         end
+
+        context 'when PROXY CIDRs are provided' do
+          it 'includes the PROXY frontend in drain logic' do
+            drain = template.render(
+              {
+                'ha_proxy' => {
+                  'drain_enable' => true,
+                  'enable_health_check_http' => true,
+                  'expect_proxy_cidrs' => ['10.0.0.0/8']
+                }
+              }
+            )
+            expect(drain).not_to include('drain is disabled')
+            expect(drain).to include('socat')
+            expect(drain).to include('disable frontend health_check_http_url_proxy_protocol')
+          end
+        end
       end
 
       context 'when a custom ha_proxy.drain_timeout is provided' do