add prometheus scraping to varnish exporter

prometheus/files/prometheus/prometheus.yml

@@ -94,3 +94,8 @@ scrape_configs:
     file_sd_configs:
       - files:
           - /etc/prometheus/targets/cadvisor.yml
+
+  - job_name: varnish
+    file_sd_configs:
+      - files:
+          - /etc/prometheus/targets/varnish.yml

prometheus/files/prometheus/targets/varnish.yml

+---
+{% set targets = salt['prometheus.prometheus_targets_for_grain']('prometheus_varnish_export') %}
+- targets: {{ targets|yaml }}

varnish/files/ferm-varnish-exporter.conf

+domain (ip ip6) {
+  table filter {
+    chain INPUT {
+      proto tcp dport (9131) saddr (185.206.209.130 2a06:8187:fb11:1::2:1) ACCEPT;
+    }
+  }
+}

varnish/init.sls

@@ -43,3 +43,14 @@ prometheus-addgroup-varnish:
     - system: True
     - addusers:
       - prometheus
+
+/etc/ferm/conf.d/40-varnish-exporter.conf:
+  file.managed:
+    - source: salt://varnish/files/ferm-varnish-exporter.conf.j2
+    - user: root
+    - group: root
+    - mode: '0644'
+
+prometheus_varnish_export:
+  grains.present:
+    - value: {{ grains.nodename }}:9131