From 6525ca5f94a9d71336d7c4e7e8f20878d46a44d1 Mon Sep 17 00:00:00 2001
From: Frank Wall <fw@moov.de>
Date: Sat, 22 Oct 2022 01:18:33 +0200
Subject: [PATCH] net/haproxy: add support for Prometheus exporter, closes
 #2764

---
 net/haproxy/pkg-descr                         |  1 +
 .../OPNsense/HAProxy/forms/dialogFrontend.xml | 14 +++++++++
 .../OPNsense/HAProxy/forms/generalStats.xml   | 27 ++++++++++++++++-
 .../app/models/OPNsense/HAProxy/HAProxy.xml   | 30 ++++++++++++++++++-
 .../templates/OPNsense/HAProxy/haproxy.conf   | 21 ++++++++++---
 5 files changed, 87 insertions(+), 6 deletions(-)

diff --git a/net/haproxy/pkg-descr b/net/haproxy/pkg-descr
index 37b084e82..2bb68861a 100644
--- a/net/haproxy/pkg-descr
+++ b/net/haproxy/pkg-descr
@@ -10,6 +10,7 @@ Plugin Changelog
 
 Added:
 * add support for req.ssl_hello_type (#2311)
+* add support for Prometheus exporter (#2764)
 
 Fixed:
 * fix unix sockets in chrooted environment (#3093)
diff --git a/net/haproxy/src/opnsense/mvc/app/controllers/OPNsense/HAProxy/forms/dialogFrontend.xml b/net/haproxy/src/opnsense/mvc/app/controllers/OPNsense/HAProxy/forms/dialogFrontend.xml
index a028a16f1..9f6fb5801 100644
--- a/net/haproxy/src/opnsense/mvc/app/controllers/OPNsense/HAProxy/forms/dialogFrontend.xml
+++ b/net/haproxy/src/opnsense/mvc/app/controllers/OPNsense/HAProxy/forms/dialogFrontend.xml
@@ -211,6 +211,20 @@
         <type>checkbox</type>
         <help><![CDATA[Enable insertion of the X-Forwarded-For header to requests sent to servers.]]></help>
     </field>
+    <field>
+        <id>frontend.prometheus_enabled</id>
+        <label>Prometheus Enabled</label>
+        <type>checkbox</type>
+        <help><![CDATA[Enable HAProxy's Prometheus exporter.]]></help>
+        <advanced>true</advanced>
+    </field>
+    <field>
+        <id>frontend.prometheus_path</id>
+        <label>Prometheus Path</label>
+        <type>text</type>
+        <help><![CDATA[The path where the Prometheus exporter can be accessed.]]></help>
+        <advanced>true</advanced>
+    </field>
     <field>
         <label>Basic Authentication</label>
         <type>header</type>
diff --git a/net/haproxy/src/opnsense/mvc/app/controllers/OPNsense/HAProxy/forms/generalStats.xml b/net/haproxy/src/opnsense/mvc/app/controllers/OPNsense/HAProxy/forms/generalStats.xml
index 6832e1e17..ad63e778e 100644
--- a/net/haproxy/src/opnsense/mvc/app/controllers/OPNsense/HAProxy/forms/generalStats.xml
+++ b/net/haproxy/src/opnsense/mvc/app/controllers/OPNsense/HAProxy/forms/generalStats.xml
@@ -5,7 +5,7 @@
     </field>
     <field>
         <id>haproxy.general.stats.enabled</id>
-        <label>Stats enabled</label>
+        <label>Enabled</label>
         <type>checkbox</type>
         <help><![CDATA[Enable HAProxy's statistics page.]]></help>
     </field>
@@ -57,4 +57,29 @@
         <help><![CDATA[These lines will be added to the statistics settings of to the HAProxy configuration file.<br/><div class="text-info"><b>NOTE:</b> The syntax will not be checked, use at your own risk!</div>]]></help>
         <advanced>true</advanced>
     </field>
+    <field>
+        <label>Prometheus Exporter</label>
+        <type>header</type>
+    </field>
+    <field>
+        <id>haproxy.general.stats.prometheus_enabled</id>
+        <label>Enabled</label>
+        <type>checkbox</type>
+        <help><![CDATA[Enable HAProxy's Prometheus exporter.]]></help>
+    </field>
+    <field>
+        <id>haproxy.general.stats.prometheus_bind</id>
+        <label>Listen addresses</label>
+        <type>select_multiple</type>
+        <style>tokenize</style>
+        <allownew>true</allownew>
+        <help><![CDATA[Configure listen addresses for the prometheus exporter, i.e. 10.0.0.1:8404 or haproxy.example.com:8404. Use TAB key to complete typing a listen address.]]></help>
+        <hint>Enter address:port here. Finish with TAB.</hint>
+    </field>
+    <field>
+        <id>haproxy.general.stats.prometheus_path</id>
+        <label>Path</label>
+        <type>text</type>
+        <help><![CDATA[The path where the Prometheus exporter can be accessed.]]></help>
+    </field>
 </form>
diff --git a/net/haproxy/src/opnsense/mvc/app/models/OPNsense/HAProxy/HAProxy.xml b/net/haproxy/src/opnsense/mvc/app/models/OPNsense/HAProxy/HAProxy.xml
index 3be9a91e1..8a81ffce3 100644
--- a/net/haproxy/src/opnsense/mvc/app/models/OPNsense/HAProxy/HAProxy.xml
+++ b/net/haproxy/src/opnsense/mvc/app/models/OPNsense/HAProxy/HAProxy.xml
@@ -1,6 +1,6 @@
 <model>
     <mount>//OPNsense/HAProxy</mount>
-    <version>3.7.0</version>
+    <version>3.8.0</version>
     <description>the HAProxy load balancer</description>
     <items>
         <general>
@@ -376,6 +376,24 @@
                 <customOptions type="TextField">
                     <Required>N</Required>
                 </customOptions>
+                <prometheus_enabled type="BooleanField">
+                    <default>0</default>
+                    <Required>N</Required>
+                </prometheus_enabled>
+                <prometheus_bind type="CSVListField">
+                    <default>*:8404</default>
+                    <Required>N</Required>
+                    <multiple>Y</multiple>
+                    <mask>/^((([0-9a-zA-Z._\-\*:\[\]]+:+[0-9]+(-[0-9]+)?|unix@[0-9a-z_\-]+)([,]){0,1}))*/u</mask>
+                    <ChangeCase>lower</ChangeCase>
+                    <ValidationMessage>Please provide a valid listen address, i.e. 10.0.0.1:8404 or haproxy.example.com:8404.</ValidationMessage>
+                </prometheus_bind>
+                <prometheus_path type="TextField">
+                    <default>/metrics</default>
+                    <Required>N</Required>
+                    <mask>/^.{1,2048}$/u</mask>
+                    <ValidationMessage>Should be a string between 1 and 2048 characters.</ValidationMessage>
+                </prometheus_path>
             </stats>
             <cache>
                 <enabled type="BooleanField">
@@ -777,6 +795,16 @@
                     <default>0</default>
                     <Required>Y</Required>
                 </forwardFor>
+                <prometheus_enabled type="BooleanField">
+                    <default>0</default>
+                    <Required>N</Required>
+                </prometheus_enabled>
+                <prometheus_path type="TextField">
+                    <default>/metrics</default>
+                    <Required>N</Required>
+                    <mask>/^.{1,2048}$/u</mask>
+                    <ValidationMessage>Should be a string between 1 and 2048 characters.</ValidationMessage>
+                </prometheus_path>
                 <connectionBehaviour type="OptionField">
                     <Required>Y</Required>
                     <default>http-keep-alive</default>
diff --git a/net/haproxy/src/opnsense/service/templates/OPNsense/HAProxy/haproxy.conf b/net/haproxy/src/opnsense/service/templates/OPNsense/HAProxy/haproxy.conf
index c6f0ff8dd..d7d910beb 100644
--- a/net/haproxy/src/opnsense/service/templates/OPNsense/HAProxy/haproxy.conf
+++ b/net/haproxy/src/opnsense/service/templates/OPNsense/HAProxy/haproxy.conf
@@ -1411,6 +1411,9 @@ frontend {{frontend.name}}
 {%       endif %}
 {%       if frontend.forwardFor == '1' and frontend.mode == 'http' %}
     option forwardfor
+{%       endif %}
+{%       if frontend.prometheus_enabled == '1' and frontend.mode == 'http' and frontend.prometheus_path|default("") != "" %}
+    http-request use-service prometheus-exporter if { path {{frontend.prometheus_path}} }
 {%       endif %}
     # tuning options
 {%       if frontend.tuning_maxConnections is defined %}
@@ -1916,7 +1919,7 @@ peers {{peers_name}}
 {#             STATISTICS          #}
 {# ############################### #}
 
-{%- if helpers.exists('OPNsense.HAProxy.general.stats') and OPNsense.HAProxy.general.stats.enabled|default("") == "1" %}
+{% if helpers.exists('OPNsense.HAProxy.general.stats') and OPNsense.HAProxy.general.stats.enabled|default("") == "1" %}
 {# # enable local stats #}
 listen local_statistics
     bind            127.0.0.1:{{OPNsense.HAProxy.general.stats.port}}
@@ -1931,7 +1934,7 @@ listen local_statistics
 {%     endfor %}
 {%   endif %}
 
-{# # remote stats are optional #}
+{#   # remote stats are optional #}
 {%   if OPNsense.HAProxy.general.stats.remoteEnabled|default("") == "1" %}
 {%     if OPNsense.HAProxy.general.stats.remoteBind|default("") != "" %}
 listen  remote_statistics
@@ -1957,8 +1960,18 @@ listen  remote_statistics
 # ERROR: remote statistics disabled, because no listen address was specified
 {%     endif %}
 {%   else %}
-# statistics are DISABLED
+# remote statistics are DISABLED
 {%   endif %}
-
+{% else %}
+# statistics are DISABLED
 {% endif %}
+
+{% if helpers.exists('OPNsense.HAProxy.general.stats') and OPNsense.HAProxy.general.stats.prometheus_enabled|default("") == "1" %}
+{# # enable prometheus exporter #}
+frontend prometheus_exporter
+   bind {{OPNsense.HAProxy.general.stats.prometheus_bind}}
+   mode http
+   http-request use-service prometheus-exporter if { path {{OPNsense.HAProxy.general.stats.prometheus_path}} }
+{% endif %}
+
 {%- endif -%}