Add extras directory to prometheus config

All files within the directory are recursively templated. This provides
a mechanism to include extra files that you can reference in
prometheus.yml, for example:

scape_targets:
  - job_name: ipmi
    params:
      module: default
    scrape_interval: 1m
    scrape_timeout: 30s
    metrics_path: /ipmi
    scheme: http
    file_sd_configs:
    - files:
      - /etc/prometheus/extras/file_sd/ipmi-exporter-targets.yml
      refresh_interval: 5m

Change-Id: Ie2f085204b71725b901a179ee51541f1f383c6fa
(cherry picked from commit cf6ef62)

ansible/roles/prometheus/handlers/main.yml

@@ -19,6 +19,7 @@
     - service.enabled | bool
     - config_json.changed | bool
       or prometheus_confs.changed | bool
+      or prometheus_extra_confs.changed | bool
       or prometheus_alerting_rules.changed | bool
       or prometheus_container.changed | bool
 

ansible/roles/prometheus/tasks/config.yml

@@ -248,6 +248,52 @@
   notify:
     - Restart prometheus-jiralert container
 
+- block:
+    - name: Find extra prometheus server config files
+      become: true
+      local_action:
+        module: find
+        paths: "{{ node_custom_config }}/prometheus/extras/"
+        patterns: "*"
+        recurse: true
+      register: prometheus_config_extras_result
+      run_once: true
+
+    - name: Create subdirectories for extra config files
+      become: true
+      vars:
+        dirs: >-
+          {{ prometheus_config_extras_result.files | default([])
+          | map(attribute='path') | map('dirname') | unique
+          | map('relpath', base) | list }}
+      file:
+        path: "{{ node_config_directory }}/prometheus-server/{{ item }}"
+        state: "directory"
+        owner: "{{ config_owner_user }}"
+        group: "{{ config_owner_group }}"
+        mode: "0770"
+        recurse: true
+      with_items: "{{ dirs }}"
+
+    - name: Template extra prometheus server config files
+      become: true
+      vars:
+        relpath: "{{ item | relpath(base) }}"
+      template:
+        src: "{{ item }}"
+        dest: "{{ node_config_directory }}/prometheus-server/{{ relpath }}"
+        mode: "0660"
+      with_items: "{{ prometheus_config_extras_result.files | default([]) | map(attribute='path') | list }}"
+      register: prometheus_extra_confs
+      notify:
+        - Restart prometheus-server container
+  vars:
+    base: "{{ node_custom_config }}/prometheus/extras/"
+    service: "{{ prometheus_services['prometheus-server']}}"
+  when:
+    - inventory_hostname in groups[service.group]
+    - service.enabled | bool
+
 - name: Check prometheus containers
   become: true
   kolla_docker: